Freight Calculations

Freight Calculations

Freight Calculations are a central part of commercial decision-making for Shipowners. Before fixing a ship, the Shipowner must compare different employment opportunities and identify which Fixture is likely to produce the strongest commercial result. The best Fixture is not always the one with the highest headline Freight Rate or Hire Rate. In practical terms, the most attractive Fixture is usually the employment that produces the highest daily revenue over the most suitable period, with payment coming from a financially reliable Charterer and with acceptable contractual risks.

A Voyage Estimation is essentially a profit-and-loss calculation for a proposed voyage. It measures the expected income against the expected expenses of transporting a particular cargo from one port to another. The Shipowner uses this calculation to decide whether the proposed Freight Rate will cover the cost of performing the voyage and still leave an acceptable profit. Although the basic principle appears simple, the actual calculation can be complex because the final result depends on ship performance, voyage duration, cargo quantity, port costs, bunkers, canal dues, Laytime, Demurrage prospects, weather, routing, Charter Party terms, and market timing.

It is not sufficient for a Shipowner to enter Chartering Negotiations by adding “a little extra” to estimated costs. Such an approach may work occasionally by chance, but it is commercially dangerous. In a Low Freight Market, the Shipowner may fail to find employment if the offer is above the level Charterers are willing to pay. In a High Freight Market, the Shipowner may fix the ship too cheaply and lose the opportunity to capture the true market value. Since depressed Freight Markets often last longer than strong Freight Markets, a Shipowner who repeatedly fixes without accurate calculations can quickly weaken cash flow and may eventually face serious financial pressure.

For every open-ship position, Shipowners normally compare several employment alternatives. One proposed voyage may produce a high daily return but leave the ship in a poor geographical position for the next employment. Another may produce a slightly lower return but position the ship in a stronger market area. A third may provide longer employment and reduce market exposure. Therefore, the calculation must not focus only on the immediate daily result. If several Alternative Voyage Calculations produce similar daily returns, the duration of the Voyage Charter or Time Charter, the redelivery position, the expected next cargo, and market direction become equally important.

Market timing is a major factor in Freight Calculations. If the Shipowner expects the Freight Market to rise, the Shipowner may prefer a shorter employment so that the ship becomes open again quickly and can be refixed at a stronger level. In that situation, the Shipowner may accept a balanced Fixture that preserves upside exposure to a rising market. If the Shipowner expects the Freight Market to weaken, the opposite strategy may be preferable. The Shipowner may seek longer employment at a Hire Rate or Freight level reflecting the current Spot Market, thereby protecting earnings before market conditions deteriorate.

Freight Calculation work is usually performed under time pressure. A ship cannot remain idle indefinitely while the Shipowner waits for a perfect cargo. Every day without employment represents lost earning potential, while operating costs continue. In many cases, there is limited time to investigate every possible cost, operational complication, port restriction, or counterparty risk. There may also be insufficient time to conduct a full credit assessment of the Charterer. For this reason, Shipowners and Shipbrokers must combine calculation discipline with practical commercial judgment.

The final result of a proposed voyage may be affected by many external factors that can only be estimated at the time of fixing. Weather, congestion, port productivity, bunker prices, canal waiting time, cargo availability, strikes, draft restrictions, and terminal delays may all change the result materially. Freight Calculation also requires translating the wording of the Charter Party Form or the Pro Forma Contract proposed by Charterers into real costs and risks. A clause that appears harmless in negotiations may have a measurable financial effect when converted into time, bunkers, port charges, liability exposure, or operational delay.

The tools used in Freight Calculation include accurate ship particulars, speed and consumption data, cargo capacity figures, bunker prices, port cost estimates, canal tariffs, agency information, and expected cargo-handling productivity. Port Agents are particularly important because they can provide practical information on Port Dues, Port Charges, Stevedoring Tariffs, berth restrictions, local taxes, customs requirements, cargo-handling rates, Draught Restrictions, tidal limitations, and other port-specific issues. Reliable Port Agents in major trading areas are therefore a valuable commercial resource for Shipowners and Shipbrokers.

Shipowners also rely on technical and operational knowledge when preparing voyage estimates. Handbooks on cargo handling, port conditions, stowage, dangerous cargoes, and shipping geography may be useful, but the most valuable information often comes from the operational staff who manage the ship in practice. During the Pre-Calculation stage, close cooperation is needed with those responsible for ship operations, bunkering, voyage instructions, performance monitoring, and compliance with current Charter Party obligations. These teams understand the ship, ports, cargoes, route, and practical constraints better than a purely theoretical calculation can show.

Operational personnel can often identify issues that may not be obvious from the Fixture recap alone. They may know that a particular port has slow discharge rates, that a berth has draft limitations, that a cargo requires special cleaning, that a canal transit may involve delay, or that a certain route increases bunker consumption. Their experience can help estimate the cost of most Chartering Alternatives and assess the practical effect of proposed Charter Party Clauses. A strong Freight Calculation therefore combines commercial market knowledge with technical and operational input.

For sound business practice, Shipowners should compare the final Voyage Estimation with the Actual Results of the Realized Voyage. This post-voyage comparison helps identify errors in the original assumptions and improves future calculations. If port time was underestimated, bunker consumption was too low, agency costs were higher than expected, or cargo intake was miscalculated, the Shipowner can adjust future estimates. Over time, this feedback process strengthens commercial accuracy and reduces repeated mistakes.

There are only a few major differences between Voyage Estimates for dry cargo ships and those for tankers, but those differences can be important. In tanker charters fixed on Worldscale terms, Laytime calculations are often more standardized because Worldscale normally includes a defined allowance for cargo operations. For example, tanker calculations often refer to continuous hours for loading and discharging or “all purposes,” together with an overall port-time allowance under the relevant Worldscale terms. This can make some elements of Laytime calculation more predictable than in dry cargo trades, where Laytime wording varies widely between Charter Parties.

Tankers also involve cost elements not usually found in dry cargo voyage calculations. One of the most important is bunker consumption for auxiliary purposes such as cargo heating, cargo pumping, and tank cleaning. Assessing Bunker (Fuel) Consumption for cargo heating is especially difficult because it depends on the cargo’s loading temperature, required carriage temperature, tank arrangement, whether the cargo is carried in wing tanks or center tanks, sea temperature, air temperature, voyage duration, weather, insulation, and the ship’s heating system. Accurate assessment often requires input from the Technical Department of the Ship Management company.

Pumping and tank cleaning may be easier to estimate than cargo heating, but they still require technical knowledge and historical data. The Technical Managers may provide average bunker consumption figures based on previous voyages, pump performance, cargo grades, tank-cleaning requirements, and the ship’s machinery characteristics. If these figures are underestimated, the voyage result may be materially weaker than expected. For tankers, therefore, Freight Calculation must integrate commercial, technical, and cargo-handling considerations with particular care.

Voyage Estimation Form

A standard Voyage Estimation Form helps Shipowners compare Chartering Alternatives in a consistent and structured way. Many Shipowners now use Voyage Estimation Software, but some still maintain internal Printed Calculation Forms or spreadsheet-based systems. The purpose is the same: to organize the relevant income, cost, time, cargo, and performance assumptions so that each proposed Fixture can be evaluated properly. A well-prepared Voyage Estimation allows the Shipowner to compare different voyages on a daily result basis and to understand how sensitive the outcome is to changes in costs or time.

Effective Voyage Estimation requires more than basic arithmetic. The estimator should understand maritime geography, ship measurements, cargo characteristics, port operations, Stowage Factors (SF), load-line zones, bunkers, weather patterns, canal routes, and conversion factors. The presentation of a Voyage Estimation may differ between companies, but the main elements are usually similar because the commercial questions are common to all Shipowners: how much cargo can be loaded, how long the voyage will take, what the voyage will cost, what income will be earned, and what daily return will result.

Key Components of a Voyage Estimation Form:

• Ship’s name and main particulars: This section identifies the ship, or the class of ship, used for the Freight Calculation. It normally includes cargo capacity, deadweight, cubic capacity, speed, bunker consumption, gear, draft, and other performance-related details. These particulars are essential because the calculation result is valid only for the ship or ship type assumed. A similar voyage performed by a different ship may produce a different result if speed, consumption, cargo intake, port suitability, or bunker requirements differ. The ship particulars therefore form the technical foundation of the Similar Voyage comparison under the same Freight Market conditions.
• Period of time: This section identifies the period for which the calculation assumptions are valid. Freight Markets, bunker prices, port costs, canal tariffs, currency rates, and cargo-handling expenses can change quickly. A voyage estimate prepared today may no longer be accurate several weeks later. Recording the calculation period helps the Shipowner understand whether the estimate reflects current market conditions or whether it must be updated before being used for negotiations.
• Intended voyage: This part describes the proposed employment, including the loading port or range, discharging port or range, expected route, and the position where the ship is expected to begin her next employment. The calculation should not stop mechanically at discharge if the ship will need to ballast to another area before she can obtain the next cargo. A realistic Voyage Plan for Freight Calculation may therefore include a Ballast Leg at the beginning, at the end, or both, depending on the ship’s position and market practice. Canals, straits, restricted waters, river passages, and other navigational routes must also be included because they may increase voyage time and add costs such as canal dues, pilotage, towage, security charges, or extra insurance.
• Cargo: This section records the commodity, cargo characteristics, cargo quantity, and the Stowage Factor (SF) used in the Freight Calculation. The Cargo Intake depends on whether the cargo is limited by weight or volume. Heavy cargoes may reach the ship’s deadweight limit before the holds are full, while light cargoes may fill the cubic space before the ship reaches her deadweight capacity. The calculation must therefore consider the relationship between Deadweight All Told (DWAT) and Deadweight Cargo Capacity (DWCC), as well as Grain Capacity, Bale Capacity, cargo density, and stowage characteristics.

Cargo intake is also affected by load-line zones, season, water density, salinity, port draft restrictions, berth limitations, under-keel clearance, trim requirements, bunker quantity, fresh water, stores, and safety reserves. A ship may have a theoretical cargo capacity, but the actual cargo quantity available for loading may be lower because of draft at the loading port, draft at the discharging port, canal restrictions, river limitations, or seasonal load-line rules. For that reason, cargo capacity must be calculated for the intended voyage, not taken blindly from the ship’s general particulars.

The Voyage Estimation Form should also record the Charter Party term that determines Laytime for loading and discharging operations. Laytime directly affects the time estimate and potential Demurrage or Despatch result. A voyage with high Freight may still produce a poor daily result if port time is excessive or if the Laytime clause places delay risk on Shipowners. Conversely, a voyage with modest Freight may become attractive if cargo operations are fast, port costs are low, and the ship is positioned well for the next employment. Accurate Laytime assumptions are therefore essential to realistic Freight Calculation.

• Freight: Freight is most commonly quoted in USD per metric ton, with one metric ton equal to 1,000 kilograms. In everyday chartering practice, the expression “metric ton” is frequently used instead of “metric tonne” or “tonne,” although the unit should always be clear in the Charter Party. In some trades, Freight may also be calculated by reference to a long ton of 1,016 kilograms, and failure to identify the correct unit can materially affect the final Freight calculation.
• For Dry Bulk Fixtures, the main limiting factor is often the ship’s available Deadweight Cargo Capacity (DWCC), because many dry bulk cargoes are homogeneous and Heavy. Iron ore, coal, bauxite, fertilizers, grain, and similar commodities are commonly calculated by weight, although the ship’s cubic capacity must still be checked where the cargo has a high Stowage Factor (SF). For Bulky Cargoes, breakbulk cargoes, general cargoes, chemicals, gases, and certain specialized trades, Freight may be expressed differently, for example in USD per cubic meter (cbm), cubic foot (cb.ft.), package, unit, or other agreed measurement.
• Freight may also be quoted under the W/M (Weight or Measurement) system. Under this method, Freight is calculated by using whichever unit, weight or volume, produces the higher Freight amount. This system is widely used in Liner Pricing and general cargo trades. In Liner Shipping, Light Cargo is often charged by volume, while Heavy Cargo is charged by weight. This is commonly described as Freight Per Revenue Ton (R/T). One Revenue Ton is usually equal to either 1 metric ton or 1 cubic meter, whichever produces greater revenue for the Carrier. The Carrier normally retains the right to apply the measurement basis that gives the higher Freight.
• In container and liner trades, the Freight Rate may also include or be supplemented by surcharges such as the Bunker Adjustment Factor (BAF) or Currency Adjustment Factor (CAF). These charges are designed to reflect movements in fuel prices, exchange rates, or other cost factors that may change after the base Freight has been agreed. Freight may also be fixed on a Lump Sum basis. Under Lump Sum Freight, the Shipowner agrees to make a specified cargo space, tonnage, or carrying capacity available to the Charterer in return for a predetermined total Freight amount, regardless of the exact cargo quantity within the agreed contractual limits.
• Costs: This section covers the Voyage Expenses connected with the particular voyage being evaluated. The largest and most volatile item is often Bunkers (Fuel) Cost, especially where the voyage is long, the ship is fuel-intensive, or bunker prices are moving quickly. Other voyage costs may include port charges, canal dues, pilotage, towage, agency fees, cargo-handling expenses, additional insurance premiums, war risk premiums, security costs, taxes, survey costs, communication costs, and other voyage-specific expenses.
• On the cost side of the Freight Calculation, Port Costs and Cargo-Handling Expenses are sometimes estimated as a Lump Sum, particularly where exact figures are not yet available. These expenses form major components of the Disbursements Account (DA), which the Port Agent presents to the Shipowner after the port call. Since Port Costs can be difficult to predict accurately before arrival, Shipowners usually obtain an Estimate (Pro-Forma Account) from Port Agents before fixing. Brokerage, address commission, protective agency, extra insurance, and other incidental costs should also be included, because even small omissions can distort the final daily result.
• Rate of Exchange: This part records the currency in which Freight will be paid and the exchange rate used for the estimate. For Voyage Estimation purposes, all income and expenses are usually converted into a common currency, most often US Dollars. This is necessary because Freight may be paid in one currency, while port costs, canal dues, agency fees, taxes, crew-related expenses, or local charges may arise in several different currencies. Exchange rate movements can affect the final result, particularly where payment is delayed or where large local expenses must be paid in a currency that has moved against the US Dollar.
• Final Result: The Freight Calculation Form ends with a summary of the expected financial result of the Voyage Estimation. This usually includes Gross Freight, Net Freight after deducting Brokerage and Commissions, total Voyage Expenses, Gross Voyage Result, Gross Daily Result, Net Daily Result, and the Time Charter Equivalent (TCE). The TCE is especially useful because it converts a Voyage Charter result into a daily figure that can be compared with Time Charter alternatives or current Spot Market earnings.

The final result of a Voyage Estimation involves:

• Adding together Brokerage and Commissions, Bunkers (Fuel), port expenses, cargo-handling costs, canal dues, additional insurance, taxes, agency fees, and other extra expenses. This total is then deducted from the adjusted Gross Freight Revenue to calculate the net income generated by the voyage after variable voyage costs have been paid.
• Dividing the resulting net income by the number of Voyage Days. This produces the daily earning figure for the ship during the proposed voyage. The calculation should include ballast time, laden time, port time, canal time, waiting time where reasonably expected, and any other period that affects the ship’s availability for the next employment.
• Using the Daily Revenue or Revenue Per Day (TCE: Time Charter Equivalent) as a commercial benchmark. This figure shows whether the voyage covers the ship’s Fixed Costs, whether it performs better than other available employment alternatives, and whether the calculated daily result is consistent with prevailing Spot Market levels.

The Shipowner’s judgment should also take into account the expected direction of the Freight Market during the voyage. A voyage that produces an acceptable daily return may still be unattractive if it leaves the ship open in a weak geographical area or at the wrong time. Conversely, a voyage with a slightly lower immediate return may be commercially stronger if it positions the ship in a rising market or close to a more profitable cargo program. The ship’s next employment opportunity is therefore an essential part of the final evaluation.

In the short term, a voyage may be considered profitable if the Revenue Per Day covers the ship’s Daily Operating Costs, including manning, crew-related expenses, repairs, maintenance, provisions, stores, spare parts, insurance, technical management, and administration. However, long-term profitability requires more than covering operating costs. The Daily Revenue must also contribute to Capital Costs, including interest, depreciation, debt repayment, loan amortization, and the owner’s return on investment. A voyage that covers only operating costs may help keep the ship employed in a weak market, but it cannot sustain the Shipowner’s business over the long term.

Stages of Freight Calculations

The Voyage Estimation process can be divided into several practical stages. Each stage converts commercial, technical, and operational information into figures that can be compared against the proposed Freight Rate or Hire Rate. A disciplined approach helps Shipowners and Shipbrokers avoid overlooking important costs and allows different employment alternatives to be compared on a consistent basis.

1- First Stage: Voyage Plan

The first stage is to prepare the Voyage Plan. At this point, the Shipbroker or commercial operator must identify the most suitable route and the appropriate Bunkering (Fueling) strategy. The voyage usually begins from the place where the ship completes discharge under the Previous Charter, often from the discharge port’s Pilot Station. Unless the ship immediately loads a new cargo at the same port or nearby, the first part of the new employment will normally be a Ballast Leg.

This method is more realistic than starting the Voyage Estimation at the Loading Port only. If the calculation begins only at the Loading Port, it may show the laden passage but ignore the time and cost required to bring the ship from her previous discharge position to the new loading area. In tanker trades, repeating similar voyage patterns may sometimes make a loading-port-to-loading-port method workable. However, bulk carriers rarely repeat identical voyages continuously. For dry bulk ships, the Discharge Port to Discharge Port Model is generally more practical because it captures the full commercial cycle from one open position to the next.

The Voyage Plan should include the loading port or range, discharging port or range, expected route, ballast passages, laden passages, canal transits, bunkering ports, weather-sensitive areas, and the location where the ship is expected to begin her next employment. The route must be chosen carefully because route selection directly affects distance, voyage duration, bunker consumption, canal dues, insurance exposure, security costs, and the final TCE result.

Several factors must be considered when building the Voyage Plan. Distance tables provide the starting point, but they should not be used mechanically. Weather conditions, seasonal routing, piracy areas, war risk zones, canal restrictions, ice conditions, traffic separation schemes, draft limits, emission control areas, port congestion, and bunker availability can all change the preferred route. The fastest route is not always the most economical route, and the cheapest route is not always commercially safe or contractually acceptable.

Bunkering strategy is also part of the first-stage calculation. The estimator must decide where the ship is likely to stem bunkers, what fuel grades will be required, how much fuel will be consumed during ballast and laden passages, how much fuel will be used in port, and what safety margin should be carried. Bunker prices may differ significantly between ports, and a small change in bunker planning can alter the voyage result. The plan should also consider whether the ship must carry additional bunkers because of limited availability at future ports, uncertain waiting time, canal delays, or bad-weather routing.

The Voyage Plan therefore forms the backbone of the entire Freight Calculation. If the route, distance, speed, bunker plan, ballast leg, or next-position assumption is wrong, the final result will also be wrong. A reliable Voyage Estimation begins with a realistic operational picture of how the ship will move from her current position, perform the cargo voyage, and reach the next commercially usable open position.

• Bunkering (Fueling) Ports: The selection of the bunkering port can have a major effect on the final voyage result. Bunkers may be stemmed at the previous discharging port, at the loading port, at the discharging port, or at a dedicated Bunkering Port En Route. If the ship stems bunkers between the loading and discharging ports, it may be possible to carry less fuel at the loading port and increase the cargo intake. However, the additional Freight earned from carrying more cargo must be compared with the extra time, port costs, agency fees, deviation, and operational expenses incurred at the bunkering port.
• If the cargo is limited by volume rather than weight, bunker weight may have less effect on the ship’s earning capacity because the ship’s holds or tanks may be full before the ship reaches her maximum deadweight. In that case, carrying additional bunkers may not reduce Freight revenue. By contrast, where the cargo is heavy and the ship is deadweight-limited, every additional ton of bunkers may reduce the quantity of cargo that can be loaded. The Freight Calculation must therefore compare the bunker price advantage against the possible loss of Freight from reduced cargo intake.
• Fuel prices at alternative bunkering ports must also be reviewed carefully. Sometimes it is more profitable to carry additional bunkers from a cheaper port, even if this reduces cargo capacity slightly. In other cases, the Freight earned on the additional cargo may exceed the saving made by buying cheaper fuel elsewhere. The correct decision depends on bunker price spreads, Freight Rate, cargo intake, voyage distance, safety margins, and the ship’s expected next employment. For this reason, Shipbrokers and operators should maintain reliable contacts with Bunkering (Fueling) Agents and bunker suppliers in major ports so that current bunker prices, availability, quality, and delivery conditions can be checked quickly.
• Maritime Atlas and Distance Tables: Accurate distance information is essential when preparing a Voyage Estimation. Digital tools and distance-table programs, such as the Netpas Distance Table (www.netpas.net), are commonly used to compare alternative routes and calculate sea distances. The Shipbroker should not assume that the shortest geographical route is automatically the best commercial route. Each possible route should be tested against cost, time, safety, canal dues, weather, piracy exposure, war risks, bunkering possibilities, and the ship’s next position.
• For example, a voyage from the US Gulf (USG) to Malaysia may be shorter via Gibraltar and the Suez Canal than via the Cape of Good Hope (COGH). However, the Suez route may involve substantial canal tolls, possible convoy or waiting delays, security considerations, and additional administrative costs. The Cape route may be longer in distance but may avoid canal dues and reduce certain transit risks. The Voyage Estimation must therefore compare the total commercial result of each route rather than focusing only on nautical miles.
• Ocean Currents and Weather Systems: Ocean currents, seasonal weather, monsoons, storms, swell, ice, and prevailing winds can materially influence route selection and voyage duration. A route that appears shorter on a distance table may produce a poorer result if the ship is likely to face heavy weather, adverse currents, or seasonal delays. The Shipbroker may need to include additional time for expected bad weather or follow the recommendations of a weather routing service appointed by the Shipowner. Weather routing can help reduce bunker consumption, avoid dangerous conditions, protect cargo, and improve the accuracy of the Voyage Estimation.
• Passages through Canals and Other Fairways: Routes involving canals, straits, rivers, locks, or restricted fairways must be examined carefully because they can either shorten or lengthen the commercial voyage depending on cost and delay. The Panama Canal and the Suez Canal are the most obvious examples, but many other passages may also affect the calculation. Canal dues, pilotage, tug assistance, waiting time, draft restrictions, beam limits, convoy systems, security requirements, and possible congestion must all be included in the Freight Calculation. A canal route may save days at sea, but the saving must be compared with the total additional cost of using the canal.
• Ship’s Speed and Bunker (Fuel) Consumption: The ship’s speed is one of the most sensitive elements in any Voyage Estimation. A small change in speed can alter voyage duration, bunker consumption, arrival time, and the daily result. In some market conditions, it may be more economical to proceed at reduced speed because the saving in fuel is greater than the value of the time lost. In other cases, proceeding at full speed may be commercially justified because earlier arrival at the loading port may allow the Shipowner to meet the cancelling date, secure a higher Freight Rate, earn Demurrage sooner, or take advantage of a rising market.
• Speed and consumption assumptions should be realistic and based on the ship’s actual performance, not merely on optimistic description figures. Weather, currents, hull condition, engine condition, draft, trim, cargo condition, fuel quality, and routing can all affect consumption. The estimator should also distinguish between ballast speed, laden speed, eco speed, full speed, and port consumption. If the ship is likely to slow steam, the Freight Calculation should reflect both lower fuel consumption and longer voyage time.
• Load-Line Zones Map: Load-line zones must be considered because they determine how deeply the ship may lawfully and safely load in different regions and seasons. For safety and environmental reasons, the oceans are divided into zones that affect the maximum permissible draft of the ship. These zones are generally connected with Winter (W), Summer (S), and Tropical (T) conditions, with the Summer Load-Line usually serving as the main reference point. The applicable zone may reduce or increase the cargo quantity that can be loaded and therefore directly affect Freight revenue.
• Water density and salinity also affect the ship’s draft and loadability. A ship floats differently in salt water and fresh water, and this must be reflected in cargo intake calculations. The Voyage Estimation must therefore consider not only the ship’s theoretical deadweight but also the load-line zone, season, water density, port draft limits, canal restrictions, river passages, under-keel clearance, and the maximum draft allowed for the intended voyage.

A ship’s International Load-Line, commonly referred to simply as the Load-Line, is the mark on the hull indicating the maximum waterline to which the ship may be loaded under specified conditions. Historically, it was known as the Plimsoll Line or Plimsoll Mark, named after Samuel Plimsoll, whose campaign for safer loading practices contributed to the Merchant Shipping Act of 1875. The purpose of the Load-Line is to prevent overloading and to preserve adequate freeboard, stability, reserve buoyancy, and safety at sea.

The distance between the Deck-Line and the Plimsoll Mark when the ship is loaded is known as freeboard. The Plimsoll Mark must be permanently marked amidships on both sides of the hull and painted in a color that contrasts clearly with the ship’s hull. This allows surveyors, port authorities, Ship Masters, and other parties to verify whether the ship is loaded within the legally permitted limits.

Ships have 6 designated Load-Lines as follows:

F – Fresh: The draft permitted when the ship is operating in fresh water. TF – Tropical Fresh: The draft permitted in tropical fresh water. T – Tropical: The draft permitted in tropical waters. S – Summer: The draft permitted in summer conditions. W – Winter: The draft permitted in winter conditions. WNA – Winter North Atlantic: The draft permitted for the severe conditions of the Winter North Atlantic.

The ship’s hull also carries the initials of the Classification Society that assigned or surveyed the Load-Line. For example:

LR – Lloyd’s Register: Indicates Lloyd’s Register as the relevant Classification Society.

Other Classification Society markings may include BV for Bureau Veritas, AB for American Bureau of Shipping, DNV for Det Norske Veritas, and similar initials used by recognized classification organizations. The Load-Line symbol, including the circle and horizontal line, forms part of the internationally recognized system for showing whether the ship is loaded within the permitted limits.

During Voyage Estimation, once the voyage legs have been identified, the Shipbroker calculates the total duration of the voyage and the expected bunker consumption. The duration includes both time at sea and time in port. Bunker consumption must be calculated separately for sea passages and port periods because the ship may consume different grades and quantities of fuel while steaming, maneuvering, loading, discharging, waiting, heating cargo, pumping, or operating auxiliary machinery.

DURATION OF THE VOYAGE = Steaming time (sailing time at sea) + Time in ports (based on laytime)

BUNKER CONSUMPTION = Bunker consumption at sea (VLSFO) + Bunker consumption in ports (VLSFO + MGO)

The Days at Sea (Sailing Time) are calculated by dividing the total voyage distance by the ship’s speed. For example, if the voyage distance is 6,000 nautical miles and the ship’s average speed is 12 knots, the sea passage would be calculated by converting speed into daily distance and then dividing the total distance accordingly. However, the mathematical result is only a starting point. The Shipbroker must also consider possible delays from canal transits, bad weather, bunkering stops, speed restrictions, congestion, ice, piracy avoidance, or other route-related factors.

For estimating purposes, it is common to allow additional time for major canal transits. In many practical calculations, around two days may be allowed for each Suez Canal or Panama Canal transit to account for waiting, convoy arrangements, pilotage, and transit time. The exact allowance should be adjusted according to current conditions, canal congestion, draft restrictions, scheduling, and any special requirements. Weather delays may also occur at sea or in port. Additional steaming time for bad weather is not always included automatically, but it should be added where the nature of the trade, season, route, or weather forecast makes delay reasonably likely.

Bunkering stops may add further time to the voyage. A simple bunkering call may require about half a day, but this can increase if the port is congested, the bunker barge is delayed, the ship must deviate, fuel samples are disputed, documentation is slow, or the ship needs several fuel grades. Multiple port calls also increase voyage time. For broad estimating purposes, one day may sometimes be allowed for each port call, but this should be adjusted where port entry, shifting, pilotage, berth waiting, cargo operations, or documentation are likely to take longer.

To calculate bunker consumption at sea, the Shipbroker multiplies the number of sailing days by the ship’s daily bunker consumption (VLSFO) at the assumed speed and condition. If the voyage includes both ballast and laden passages, each leg should be calculated separately because speed and consumption may differ. If the ship is expected to slow steam, proceed at eco speed, or operate in adverse weather, the consumption figure should be adjusted accordingly.

Time spent in ports must then be calculated by reference to the Charter Party terms for loading and unloading (Definite Laytime). The Shipbroker should add any expected waiting time, holidays, bad weather interruptions, port congestion, shifting time, documentation time, and other realistic allowances. BIMCO and other maritime information sources provide useful information on port working hours, local holidays, and customary port practices, but the most reliable current information often comes from Port Agents and local operators.

Port bunker consumption is calculated by multiplying the number of port days by the ship’s daily consumption of VLSFO and MGO while in port. In some cases, MGO consumption may be higher in port because auxiliary engines, boilers, cargo systems, cranes, pumps, or emission-control requirements may apply. Tankers may also consume additional fuel for cargo heating, pumping, tank cleaning, inert gas systems, or stripping operations. These items should be estimated separately where they are material.

Calculating time in loading and discharging ports becomes more complicated when the Charter Party specifies a rate of loading or discharging in tons per day (Calculable Laytime). In that case, the Shipbroker must first determine the cargo quantity to be loaded, usually during the second stage of the Voyage Estimation, before port time and port bunker consumption can be finalized. If the ship is expected to load 60,000 metric tons and the loading rate is 15,000 metric tons per weather working day, the basic loading time must be calculated from that rate before adding any allowed interruptions or exceptions.

This difficulty is less common in tanker chartering where the Charter Party often uses a more standardized Laytime allowance. Under Worldscale-based tanker fixtures, 72 hours “all purposes” Laytime is frequently used for loading and discharging combined, although the actual wording of the Charter Party must always be checked. Even in tanker trades, however, port time can still be affected by berth congestion, terminal restrictions, pumping performance, cargo heating, cargo sampling, documentation, inspections, weather, and port authority requirements. Therefore, standardized Laytime does not remove the need for careful practical estimation.

2- Second Stage: Cargo Measurement

In Voyage Estimation, the second stage is to determine how much cargo the ship can realistically and lawfully load. The Shipbroker must calculate the maximum cargo weight that can be lifted while also confirming that the ship’s Cubic Capacity is sufficient for the cargo volume. In some cases, the ship may have enough deadweight available but insufficient hold space, meaning that the cargo becomes volume-limited rather than weight-limited. For this reason, cargo measurement requires both a weight calculation and a space calculation.

The ship’s carrying capacity is normally assessed in two main ways:

• Tonnage Capacity: This refers to the ship’s carrying capacity by weight, usually expressed through Deadweight (DWT).
• Volume Capacity: This refers to the ship’s available cargo space, commonly described as Registered Tonnage (RT) or Cubic Capacity, measured in cubic meters or cubic feet.

Breaking down Deadweight Tonnage Capacity involves:

• Deadweight All Told (DWAT): This is the total weight the ship can carry, including cargo, bunkers, stores, fresh water, lubricants, provisions, spare parts, crew effects, and other constants.
• Deadweight Cargo Capacity (DWCC): This is the weight available for cargo after deducting bunkers, constants, fresh water, stores, and other non-cargo weights from the ship’s total deadweight capacity.

The calculation of Registered Tonnage includes:

• Gross Registered Tonnage (GRT): This measures the total enclosed volume of the ship in registered tons, with one registered ton equal to 100 cubic feet.
• Net Registered Tonnage (NRT): This measures the ship’s revenue-earning or cargo-related enclosed space after deducting spaces used for machinery, crew accommodation, and other non-cargo purposes.

Considering Cubic Capacity:

• Grain Capacity: This represents the total underdeck capacity available for free-flowing bulk cargoes such as grain. It includes spaces between frames and structural members that can be filled by loose homogeneous cargo and therefore reflects a higher usable volume.
• Bale Capacity: This represents the underdeck capacity available for general cargo, packaged cargo, bales, cartons, cases, bags, pallets, and similar cargoes that cannot fill all spaces between frames, beams, and cargo battens. Bale Capacity therefore excludes certain void spaces and is usually lower than Grain Capacity.

Broken Stowage refers to the unused cargo space that inevitably remains in a hold because of the cargo’s shape, packaging, arrangement, or the ship’s internal structure. Irregularly shaped cargoes, bagged cargoes, machinery, project cargo, timber, steel products, and other non-uniform cargoes often create Broken Stowage because they cannot be packed perfectly into every part of the hold.

When trying to maximize cargo intake and revenue, the Shipbroker first checks whether there are any Draught (Draft) Restrictions at the loading port, discharging port, canals, rivers, berths, fairways, or anchorages along the intended voyage. It is not enough to confirm that the port itself has sufficient depth. The Shipbroker must also confirm that the channel, entrance, turning basin, berth pocket, alongside depth, and cargo-handling berth can safely accommodate the ship at the intended draught. A port may be open to the ship in general terms, but the actual berth may impose a stricter draught limit.

If the ports and berths provide sufficient draught, the Shipbroker then considers the Load Line Zones applicable to the voyage. Load Line Zones are important because they determine how deeply the ship may load in different regions and seasons. These zones influence cargo intake and bunker planning. A ship may be able to load more cargo in a Tropical Zone than in a Winter Zone, but the Shipbroker must ensure that the ship remains compliant throughout the voyage as she passes from one zone into another.

At this point in the Voyage Estimation, the Shipbroker calculates cargo lifting and Bunker Replenishment together. The permissible draught and deadweight allowance for each part of the voyage are checked against the ship’s Capacity Plan (CP), Deadweight Scale, and General Arrangement (GA). These documents show the relationship between draught, deadweight, displacement, cargo space, tanks, holds, and ship arrangement. The Deadweight Scale is especially useful when the ship will call at draught-restricted ports or load in water of different density.

The Deadweight Scale also helps the Shipbroker estimate the effect of loading in Fresh Water (FW) or Brackish Water (BW), which is common in rivers, estuaries, and certain ports. Since fresh water is less dense than sea water, the ship will sink deeper in fresh water than in salt water for the same weight. This affects how much cargo can be loaded without exceeding the permitted load line once the ship moves into sea water.

TPC (Tonnes Per Centimetre immersion) indicates how many tonnes must be loaded or discharged to change the ship’s mean draught by one centimetre. The value varies according to the ship’s size, hull form, and present loading condition. TPI (Tons Per Inch immersion) serves the same purpose in imperial measurement, showing how many tons are required to change the ship’s draught by one inch.

The Deadweight Scale shows the ship’s deadweight and displacement at different draughts in salt water and fresh water. Displacement Tonnage is the actual weight of the ship and everything on board. It is based on Archimedes’ principle, which states that a floating body displaces a quantity of water equal to its own weight. Loaded Displacement is the total weight of the ship, cargo, bunkers, stores, water, and all other items on board. Light Displacement Tonnage (LDT) is the weight of the empty ship without cargo, bunkers, stores, or consumables. Therefore:

LOADED DISPLACEMENT =

LIGHT DISPLACEMENT TONNAGE (LDT) + DEADWEIGHT TONNAGE (DWT)

The Deadweight Scale normally contains columns showing Freeboard (F), Deadweight (DWT) in salt water and fresh water, mean draught, displacement in salt water and fresh water, Tonnes Per Centimetre immersion (TPC) in Salt Water and fresh water, and Moment To Change Trim 1 cm (MCTC or MTCTC). These figures allow the Shipbroker, Ship Master, and cargo planner to estimate how changes in cargo, bunkers, ballast, or stores will affect draught, trim, and loading capacity.

Trim is the longitudinal inclination of the ship, calculated by comparing the Forward Draught and the Aft Draught. A ship is said to have positive trim, or to be “trimmed by the stern,” when the Aft Draught is greater than the Forward Draught. This is common in many operating conditions. A ship is “trimmed by the head” when the Forward Draught is greater than the Aft Draught. Trim can be changed by shifting, loading, or discharging cargo, bunkers, ballast, or other weights. MCTC measures the moment required to change trim by 1 centimetre, while MCTI measures the moment required to change trim by 1 inch. These values are found in the ship’s stability book and are important for safe loading and voyage planning.

The Deadweight Scale (DS) also shows how the ship’s available tonnage changes with each change in draught. By reading across the scale at a given draught, the Shipbroker can estimate the ship’s Deadweight (DWT) in either salt water or fresh water. This is particularly important when calculating cargo intake at ports with depth restrictions, variable water density, or tidal limitations.

Fresh Water Allowance (FWA) is an important concept for ships loading in fresh water. One cubic metre of fresh water weighs approximately 1,000 kilograms, while one cubic metre of salt water weighs approximately 1,025 kilograms. Because salt water is denser, the ship floats higher in salt water than in fresh water when carrying the same weight. When a ship moves from salt water into fresh water, she sinks deeper; when she moves from fresh water into salt water, she rises. This difference is known as Fresh Water Allowance (FWA).

Fresh Water Allowance (FWA) is measured as the vertical distance between the top of the Summer (S) Load Line and the top of the Fresh (F) Load Line. Correct use of the Fresh Water Allowance (FWA) can increase cargo intake and prevent loss of revenue. If a ship loads only to the Summer (S) Load Line while in fresh water, she may be underloaded for the sea passage. By using the Fresh Water Allowance correctly, the ship may load deeper in fresh water and then rise to the Summer (S) Load Line when she reaches salt water.

When a ship loads in Brackish Water (BW), the water density lies between fresh water and salt water. In such cases, the Port Agent should obtain accurate dock-water density information or arrange for the water to be tested with a hydrometer. The additional permissible immersion is then calculated as a proportion of the Fresh Water Allowance (FWA). This is known as the Brackish Water Allowance (BWA). Accurate BWA calculation can make a meaningful difference to cargo intake, especially for large bulk carriers loading heavy cargoes.

When calculating the applicable Deadweight (DWT), the Shipbroker must deduct the expected bunkers on board at the relevant stage of the voyage, together with Constant Weights. These constants include stores, fresh water, lubricants, spare parts, crew effects, provisions, and other non-cargo items. The Shipbroker must also allow a safe bunker reserve for each voyage leg. A typical safety margin may be around 15–25%, in addition to the actual bunkers needed for normal voyage consumption, although the appropriate reserve depends on the voyage, weather, route, bunkering opportunities, port congestion, and company policy.

After deducting bunkers and constants from the ship’s available deadweight, the remaining figure represents the maximum cargo weight the ship can carry, known as Deadweight Cargo Capacity (DWCC).

DWCC = DWAT – (BUNKERS + CONSTANTS)

The Shipbroker must then verify whether the ship has enough space to carry that cargo weight. The cargo weight multiplied by the Stowage Factor (SF) gives the volume that the cargo is expected to occupy in the holds. This volume should include an allowance for Broken Stowage, especially where the cargo is irregular, packaged, or difficult to stow efficiently. The required cargo volume must not exceed the ship’s available Grain Capacity or Bale Capacity, depending on the cargo type.

In simplified form, the relationship can be expressed as:

DWCC = CUBIC CAPACITY (GRAIN OR BALE) ÷ STOWAGE FACTOR

or:

CUBIC CAPACITY (GRAIN OR BALE) = DWCC × STOWAGE FACTOR

Cargoes with a Stowage Factor (SF) of less than one cubic metre per tonne, or less than about 40 cubic feet per long ton of 2,240 lb, are usually limited by weight. Cargoes with a Stowage Factor (SF) greater than one cubic metre per tonne are often limited by volume. However, this is only a general guide. The final result depends on the ship’s actual hold shape, cargo distribution, broken stowage, draft limits, load line zones, and operational constraints.

For non-bulk cargoes, especially cargoes that are large in volume compared with their weight, the Broken Stowage allowance included in the Stowage Factor (SF) provided by Charterers or Shippers may be too optimistic. Sometimes the stated volume is “net on quay,” meaning that it does not fully account for the additional space lost when the cargo is physically stowed inside the ship’s holds. Shipowners must therefore calculate whether an extra allowance is needed for Broken Stowage on board. Failure to do so may result in short shipment, reduced Freight, loading delays, or disputes over cargo capacity.

Once the cargo quantity and loading or discharging rates per day have been established, the Shipbroker can calculate expected port time and bunker consumption in port. If the Charter Party uses a loading or discharging rate, port time cannot be finalized until the cargo quantity is known. At this stage of Freight Calculations, the Shipbroker should also consider possible delays caused by holidays, weather interruptions, port congestion, shifting, inspections, documentation, customs procedures, terminal restrictions, or slow cargo operations. Accurate cargo measurement therefore affects not only Freight revenue but also Laytime, port expenses, bunker consumption, and the final Time Charter Equivalent (TCE).

3- Third Stage: Calculation of Costs

The third stage of Voyage Estimation is the calculation of costs. At this point, the Shipbroker or Shipowner estimates the Voyage Costs, meaning the Variable Costs directly connected with the proposed voyage. These costs normally include bunkers, port dues, canal dues, transit charges, cargo-handling expenses, additional insurance premiums, agency costs, security expenses, taxes, and other voyage-related items. Among these, bunker cost is usually the largest and most sensitive expense, particularly on long voyages or during periods of volatile fuel prices.

The quantity of bunker consumed during a voyage depends on several factors, including the ship’s hull condition, engine efficiency, draught, trim, weather, current, route, and operating speed. Speed is especially important because bunker consumption does not increase or decrease in a simple linear way. A small increase in speed can produce a much larger increase in fuel consumption. Therefore, the choice between full speed, eco speed, and slow steaming can materially affect the final voyage result.

The relationship between bunker prices and Freight Rates is central to speed decisions. When Freight Rates are low and bunker prices are high, Shipowners often use slow steaming to reduce voyage costs. When Freight Rates are strong, or when early arrival creates commercial advantage, it may be more profitable to steam faster despite higher fuel consumption. The correct choice depends on the expected Freight income, bunker price, voyage duration, Laycan, next employment, and the market outlook.

Modern ships commonly burn Very Low Sulphur Fuel Oil (VLSFO) in the main engine, while auxiliary engines often consume lighter and more expensive Marine Gas Oil (MGO). For this reason, the Voyage Estimation should normally calculate VLSFO and MGO separately. VLSFO is closely connected with sailing distance and main engine use, while MGO may be consumed by auxiliary engines in port, during maneuvering, while operating cargo gear, or when emission-control or machinery requirements make its use necessary.

For voyage calculation purposes, Marine Gas Oil (MGO) consumption is sometimes counted only during port stays, particularly where the ship has a shaft generator and can produce electrical power at sea without relying heavily on auxiliary engines. However, this depends on the ship’s technical arrangement and fuel system. Modern ships are generally more fuel-efficient than older ships, and fuel efficiency has become a major commercial factor in chartering. During periods of low Freight Rates and high oil prices, shipyards and owners promoted “Eco-Ships” as a way to reduce consumption and improve competitiveness, although the commercial urgency of this trend weakened when oil prices declined.

The ship’s particulars or the ship description in the Charter Party normally state the ship’s Performance Speed and bunker consumption. This speed represents the average speed the ship is designed or expected to maintain under Normal Weather Conditions. It is a key input in Voyage Estimation. Bunker (Fuel) Consumption at a given speed depends heavily on hull design, engine type, propeller condition, and hull smoothness. Between drydockings, marine growth on the hull and propeller can increase resistance and reduce speed. In severe fouling cases, the ship may lose 2 to 3 knots compared with clean-hull performance.

VOYAGE COSTS:

• BUNKERS
• PORT DUES & CHARGES
• COMMISSIONS/BROKERAGE
• LOAD/DISCHARGE
• EXTRA INSURANCE
• MISCELLANEOUS

OPERATING OR RUNNING COSTS:

• ADMINISTRATION (SHORE)
• CREWING OR MANNING
• MAINTENANCE & MATERIALS
• REPAIR & SPARE PARTS
• DRYDOCKING/SPECIAL SURVEY CLASS & CERTIFICATES
• INSURANCE & CLAIMS
• LUBOIL & FRESHWATER

CAPITAL COSTS:

• LOAN CAPITAL & INTEREST
• DEPRECIATION

The Time Charter Equivalent (TCE) is the daily revenue produced by a voyage after deducting Voyage Costs from total voyage income and dividing the balance by the number of voyage days. Voyage days include ballast days, days at sea, time in port, and any expected waiting or transit time that forms part of the commercial voyage. In some market discussions, the fixed-cost comparison element is also referred to as the T/C-equivalent result. For Shipowners, the COMPARISON FACTOR in daily employment decisions includes comparing the voyage revenue per day with:

• Total ship costs;
• Current market level and expected market development;
• Alternative employment opportunities and competing markets;
• Lay-up, sale, or other strategic options.

Operating a ship at reduced speed can reduce bunker consumption because of decreased water resistance. Even a small reduction in average speed may produce a meaningful saving in fuel over a long voyage. In some circumstances, it may be commercially sensible to extend the voyage by several days in order to reduce bunker costs through slow steaming. However, this decision must be balanced against the value of time, Hire or Freight income, Laycan obligations, cargo commitments, and the next employment opportunity. A fully Laden ship usually consumes substantially more bunker than the same ship in Ballast at the same speed, so ballast and laden legs should be calculated separately.

Ships of similar size and speed may have very different bunker (fuel) consumption profiles. The actual bunker cost for any given voyage may vary according to several factors, including:

• Draught (Draft) and Load Line zones applicable during the voyage;
• Bunker (Fuel) price movements caused by geopolitical, commercial, and economic conditions;
• Variability in bunker (fuel) prices between different bunkering ports, where more frequent bunker calls may reduce bunker weight and increase cargo space but may also create additional time, risk, deviation, and cost;
• Differences in bunker (fuel) prices between fuel supplied from shore installations and fuel delivered on board by barge or tanker truck, since bringing the ship alongside an installation may involve expensive tug, pilotage, berth, and port charges;
• The relationship between bunker (fuel) prices and Freight Income, because in some cases the saving achieved by carrying cheaper Extra Bunkers may exceed the Freight lost by reducing cargo intake.

Simply adding a fixed percentage, such as 5%, to all tabulated distances for Adverse Weather Conditions and Currents is a rough method and may be inadequate where the financial exposure is substantial. Weather and current effects should be assessed with greater care where the voyage is long, the bunker bill is high, or the route is seasonally exposed. Modern Weather Routing System services can provide guidance on expected wind, waves, ocean currents, storm systems, and recommended routing. Ocean currents are well mapped in many trading areas and can have a measurable effect on speed over ground and bunker consumption.

Some routes may benefit from favorable currents, while the opposite direction may suffer from adverse currents. For example, a ship sailing from Gibraltar toward the Colombian East Coast under certain conditions may benefit from prevailing currents and gain one or two knots over part of the passage. A ship sailing the reverse route may experience the opposite effect. These factors are important not only for Voyage Estimation but also for later Speed Claims, because weather, current, and routing evidence may determine whether the ship performed in accordance with the Charter Party description.

In Voyage Estimations, the theoretical distance or calculated sea time for a cargo voyage, including connecting Ballast Legs, may be adjusted by practical allowances. Some estimators add a fixed percentage to the total distance, while others add One (1) Day for each canal transit or use more specific allowances for bad weather, strong currents, bunkering, speed reductions, or congestion. The pre-calculated sea voyage time then determines the ship’s estimated bunker consumption and the cost of bunker (VLSFO: Very Low Sulphur Fuel Oil) required for the intended voyage.

MGO (Marine Gas Oil) consumption varies within a daily range depending on which Auxiliary Engines are running and what operations are being performed. For Freight Calculation, an average daily MGO consumption figure is normally used. This figure is usually based on the ship’s official particulars, technical records, and statistics from previous voyages. If the voyage involves heavy use of cranes, pumps, cargo heating, tank cleaning, or emission-control requirements, the average figure should be adjusted.

The combined total of sea days and port days gives the Total Voyage Time. This figure is used for MGO consumption calculations, except for ships with shaft generators where MGO may be calculated mainly for port time. The same Total Voyage Days figure is also used in the final Freight Calculation to determine the revenue per day. Bunker prices for VLSFO and MGO vary significantly between dates and locations. Not every port has bunkering facilities, and some ports may not offer all required fuel grades. Fuel availability, quality, delivery method, and price must therefore be checked before finalizing the estimate.

In Voyage Estimation, the Shipbroker must calculate the likely Bunkers Cost carefully. If the Bunkers Remaining Onboard (ROB) at the start of the voyage are insufficient to perform the charter safely, the Shipbroker must calculate the Extra Bunkers required at sea and in port based on the ship’s estimated consumption. The cost calculation should distinguish between fuel already on board, fuel to be purchased for sea passage, and fuel required for port operations.

TOTAL BUNKERS COST = BUNKERS REMAINING ONBOARD (ROB) × FUEL PRICE ON THE DATE OF PURCHASE + EXTRA BUNKERS REQUIRED AT SEA × PRESENT FUEL PRICE + EXTRA BUNKERS REQUIRED IN PORTS × PRESENT FUEL PRICE

Port Expenses form another major part of Voyage Costs. These expenses include the charges imposed on the ship and/or cargo for using port facilities, port services, and local infrastructure. All costs incurred from Arriving Pilot Station (APS) or Taking Inward Pilot (TIP) until Dropping Outward Pilot (DOP) should be estimated as accurately as possible. Port Charges may be calculated by reference to cargo volume, cargo weight, the ship’s Gross Tonnage (GT), the ship’s Net Tonnage (NT), length, draught, port stay, or the nature of the services used.

The actual amount of port expenses depends on the port authority’s tariff policy, the ship’s size, the type and quantity of cargo handled, the berth used, and the duration of the port stay. Predicting port expenses is often difficult because local tariffs may change, discounts may apply, terminal charges may differ, and additional services may be required after arrival. Costs such as pilotage, towage, mooring, launch hire, garbage disposal, security, customs, immigration, shifting, light dues, anchorage dues, berth hire, and agency fees may all affect the final Disbursements Account.

Organizations such as BIMCO (Baltic and International Maritime Council) and INTERTANKO (International Association of Independent Tanker Owners) provide useful port-cost information, but port charges can still be difficult to assess accurately from published sources alone. Local practices, port authority interpretation, berth-specific rules, cargo requirements, and temporary surcharges may materially affect the final cost.

The most reliable method for estimating port expenses is to use experience and consult competent Port Agents with current local knowledge. To prepare an accurate estimate, the Port Agent needs full details from the Shipowner or Shipbroker, including the ship’s Net Tonnage (NT), Gross Tonnage (GT), length overall, beam, draught, cargo type, cargo quantity, intended berth, expected arrival and departure, special equipment, flag, and any unusual operational requirements. The Port Agent also needs to know what the ship will do in port because the berth, cargo operation, waiting period, shifting, and services required will directly influence the final port-cost estimate.

After the relevant port-cost calculations have been made, the Port Agent usually provides the Shipowner with a Pro-Forma Disbursement Account (PDA). The PDA sets out the estimated expenses expected to arise during the port call and serves as a working forecast for the Actual Disbursement Account (ADA). Although the PDA should be as accurate as possible, the final ADA may differ because of changes in port stay, berth allocation, cargo operations, towage, pilotage, shifting, local charges, or services actually used. For Voyage Estimation purposes, the Shipbroker must distinguish carefully between voyage expenses and operational or running costs in the Disbursement Account (DA). Only costs properly connected with the voyage should be entered under Port Expenses in the Voyage Estimation.

Canal Transit Expenses require the same level of attention as port disbursements. It is not enough to calculate only the basic canal dues. Additional expenses may arise from agency, towage, escort services, pilotage, security, waiting time, measurement formalities, documentation, and other transit-related services. Before estimating the cost of a canal or restricted fairway passage, the Shipbroker should consult experienced Local Port Agents or canal specialists. The Suez Canal is a good example because its toll system is complex and is based on Special Drawing Rights (SDRs) per Suez Canal Net Tonnage (SCNT), using measurement principles that originate from older nineteenth-century tonnage rules.

The Suez Canal Net Tonnage (SCNT) broadly reflects cargo-carrying space below deck and does not correspond neatly with modern commercial measures of cargo capacity. The relevant Suez Canal Net Tonnage (SCNT) certificate is normally issued by a classification society. The total cost of transiting the Suez Canal depends on several factors, including ship type, Suez Canal Net Tonnage (SCNT), Gross Tonnage (GT), draught, beam, whether the ship is Laden or in Ballast, and the direction of the transit. Panama Canal expenses are generally easier to identify because they are charged in US Dollars and are based on Panama Canal Net Tonnage (PCNT), although the final calculation may still involve booking fees, reservation systems, tug assistance, draught restrictions, and transit priority.

In Voyage Estimation, the Shipbroker must also calculate Cargo-Handling Expenses. These may include loading, trimming, stowage, lashing, securing, dunnaging, tallying, discharge, hold cleaning, cargo surveys, and other cargo-related operations. Depending on the commodity and Charter Party terms, these expenses can be substantial. Dunnage, lashing, securing, special grabs, shore cranes, terminal equipment, hold preparation, or cleaning after dirty cargoes may materially affect the final voyage result. The original cargo order and the Charter Party wording should therefore describe clearly how cargo-handling costs are divided between Shipowners and Charterers. Estimating these costs in advance is often difficult and may require rough calculations supported by Port Agent advice, local tariff information, and previous experience.

If the Charter Party is fixed on FIO Terms (Free In Out), the Charterer is normally responsible for arranging and paying for loading and discharging expenses.

FIO (Free In and Out): FIO is a common Voyage Charter Party term in bulk shipping. It means that the agreed Freight rate does not include the cost or arrangement of loading and discharging. These responsibilities are placed on Charterers. Since Shipowners do not control the cargo-handling process under FIO terms, the Charter Party normally includes Laytime and Demurrage provisions to protect Shipowners against delay at the loading and discharging ports. If the parties intend FIO to include additional operations such as stowing, dunnaging, lashing, securing, tallying, or trimming, this must be stated expressly in the Charter Party.

FIOS (Free In Out Stowed): FIOS follows the FIO structure but adds stowage to the responsibilities of Charterers or Shippers. It is commonly used where the safe and efficient arrangement of cargo inside the holds is commercially important, especially in general cargo, steel, bagged cargo, timber, and certain breakbulk trades.

FIOT (Free In Out Trimmed): FIOT is similar to FIO, but trimming is also placed on Charterers or Shippers. This term is often used for bulk cargoes where the cargo must be leveled or distributed properly in the holds for safe carriage, stability, and efficient discharge.

FIOST (Free In Out Stowed Trimmed): FIOST extends FIO by making Charterers responsible for both stowage and trimming. This wording is often used where the Shipowner wants the Freight rate to exclude the full range of cargo-handling obligations connected with placing the cargo properly on board.

FIOSPT (Free In Out Spout-Trimmed): FIOSPT is a variation of FIO that includes spout-trimming. It is commonly used for dry bulk cargoes such as grain, where cargo is loaded through spouts or conveyor systems and must be distributed evenly within the holds.

FIOLSD (Free In Out Lashed, Secured, and Dunnaged): FIOLSD expands the FIO principle by placing lashing, securing, and dunnaging responsibilities on Charterers or Shippers. It is particularly relevant for containers, breakbulk, project cargo, steel, machinery, and other cargoes requiring physical securing for safe transportation.

Gross Terms (GT): Gross Terms describe a Voyage Charter arrangement where Shipowners are responsible for arranging and paying the costs of loading and discharging. This structure places a wider operational and cost burden on Shipowners and must therefore be reflected in the Freight calculation.

Liner Terms (LT): Liner Terms generally mean that Freight includes ocean carriage and cargo-handling at the loading and discharging ports according to local custom. However, local customs vary considerably between ports and trades. Liner In, Liner Out, or mixed versions may also be used, and the exact division of responsibilities should always be defined clearly.

Where Charter Parties are fixed on Gross Terms or Liner Terms, Shipowners may be responsible for arranging and paying loading and discharging costs. In such cases, the Shipbroker should consult the Local Port Agent to determine the extent of the Shipowner’s responsibility, the likely cost of cargo operations, and the expected time required. These terms can have a major effect on Voyage Estimation because they shift cargo-handling costs from Charterers to Shipowners.

When Gross Terms or Liner Terms are used, Laytime may not operate in the usual FIO sense because Shipowners may be controlling or paying for cargo operations. Nevertheless, the parties may still negotiate wording requiring prompt and efficient cargo handling to protect Shipowners against excessive delay. If cargo handling is slower than expected and the delay is not covered by a Demurrage regime, Shipowners may need to claim Damages For Detention (DFD) instead of Demurrage (D), depending on the wording of the Charter Party and the circumstances of the delay.

Other expressions, including Berth Terms, LI/FO (Liner In/Free Out), and FI/LO (Free In/Liner Out), allocate responsibility for loading and discharging in different ways. These terms should not be used casually. Each must be defined in the Charter Party so that both parties understand which costs, risks, and operational responsibilities belong to Shipowners and which belong to Charterers.

Berth Terms: Berth Terms is an older and often ambiguous expression. It is sometimes treated as similar to Liner Terms or Gross Terms, indicating that cargo-handling arrangements and expenses are for Shipowners’ account and that the contract of carriage is subject to the customs and conditions of the loading and discharging ports. Because the term can be interpreted differently in different trades, it should be avoided unless its meaning is expressly stated.

LI/FO (Liner In / Free Out): Under LI/FO terms, Shipowners are responsible for loading costs, and Freight covers sea carriage and the cost of loading. Discharging costs are for Charterers’ account. The Charter Party may include Laytime and Demurrage provisions for the discharging port because Charterers control or bear responsibility for discharge.

FI/LO (Free In / Liner Out) or FI/LTD (Free In / Liner Term Discharge): These terms operate in the opposite way. Loading arrangements and costs are for Charterers or Shippers, while Freight includes sea carriage and discharging costs. Laytime and Demurrage provisions may therefore be needed at the loading port, where Charterers have responsibility for cargo operations.

During pre-calculation, the Shipbroker should use information from Port Agents at the intended ports and combine it with previous operational experience concerning slow or Quick Despatch (QD). This is the practical speed at which the ship can be handled in port. Estimating Despatch Time in ports is essential because port time directly affects voyage duration, bunker consumption, Demurrage exposure, Despatch liability, and the final Time Charter Equivalent (TCE). Outside liner trades, it is common to plan cargo operations on the basis of normal working hours in order to create a safety margin, even where local practice sometimes allows second shifts or continuous operations.

Where FIO (Free In and Out) terms are agreed, Charterers should also commit to realistic cargo-handling productivity levels. These are normally expressed as loading and discharging rates and become important points in Freight Negotiations. A high Freight Rate may be unattractive if the Charter Party allows slow cargo operations. Conversely, a moderate Freight Rate may produce a strong daily result if cargo handling is fast and port time is short.

Shipowners must assess whether the loading and discharging rates proposed by Charterers are realistic. This assessment should be based on Port Agent advice, terminal history, previous voyages, commodity characteristics, berth equipment, weather exposure, labor availability, shore storage, customs procedures, and local working practices. The Load/Discharge Rates are normally written into the Laytime Clause of the Charter Party, either as metric tons per day, metric tons per weather working day, or as a fixed number of days allowed for loading and discharging.

Expressions such as Fast As Can (FAC), Custom of Port (COP), and Customary Quick Despatch (CQD) may also be used, but they can be unclear and frequently create disputes. These terms depend heavily on local practice and factual evidence. If the parties want certainty, it is usually better to agree specific loading and discharging rates, clear working-time rules, and defined Laytime exceptions rather than relying on broad customary expressions.

The Laytime Clause should also state whether Sundays, holidays, and other non-working periods count as Laytime. If SHEX is used, Sundays and holidays are excluded from Laytime, which may extend the time required for loading or discharging. If SHINC is used, Sundays and holidays are included, which may shorten the contractual time available to Charterers. The difference can materially affect the voyage estimate, especially where port calls coincide with weekends, national holidays, religious holidays, or local non-working periods.

If Shipowners accept the loading and discharging figures proposed by Charterers as realistic, they can calculate the Effective Net Port Time by dividing the total cargo quantity by the agreed or expected loading and discharging rate at each port. For example, if 60,000 metric tons are to be loaded at 15,000 metric tons per day, the basic loading time is four days before any additional allowance for NOR tendering, turn time, weather interruptions, holidays, shifting, or documentation.

Other time factors may extend the port stay. One important element is the period between tendering the Notice of Readiness (NOR) and the commencement of Laytime. Shipowners often allow for these Notice Days or Turn Time (TT) by adding an extra day per port in the Voyage Calculation, although each Fixture should be assessed separately. Delays may also occur if cargo STEM is not available, if the ship arrives before the cargo is ready, if terminal documents are delayed, or if the ship must shift between anchorages, berths, or loading/discharging places.

If the agreed loading or discharging rate in the Charter Party is lower than the Actual Rate achieved in port, the ship may complete operations earlier than the contractual allowance. In that case, Charterers may become entitled to Despatch Money (DM), if the Charter Party provides for Despatch. If the ship remains in port longer than the agreed Laytime, Charterers will usually compensate Shipowners by paying Demurrage (D). Both possibilities must be considered in the Freight Calculation because they can change the final voyage result significantly.

Despatch and Demurrage provisions are especially important when negotiating FIO Terms. In dry bulk shipping, Despatch Money (DM) is commonly agreed at half the Demurrage (D) rate, although the exact percentage depends on the Charter Party and the bargaining position of the parties. Accurate calculation of port days is essential because even a small error in estimated loading or discharging time can materially alter the final Voyage Result. The Demurrage rate should also be set at a level that properly reflects the Shipowner’s exposure to delay, including Hire equivalent, bunker consumption, port costs, operating expenses, and the opportunity cost of losing the ship’s next employment. These amounts must be incorporated into the Voyage Calculation from the beginning.

Two other important cost items frequently arise in Voyage Estimation: Extra Insurance Premiums (EIP) and Taxes (T). Extra Insurance Premiums (EIP) may become payable when the ship is ordered outside the geographical limits imposed by hull underwriters, war-risk insurers, or other insurance arrangements. Additional premiums may also arise where the ship is considered over-age by cargo underwriters, where the ship is ordered to a politically sensitive or war-risk area, or where the intended trade creates exposure beyond the ship’s ordinary insurance cover.

Other additional insurance-related expenses may also need to be included in the calculation. For example, cargo carried on Deck at Shipowners’ Risk may not be covered under standard insurance arrangements and may require separate cover or special approval. Questions may also arise concerning War Risk Bonuses or other special payments to the Ship Master, officers, and crew when the voyage involves dangerous or sensitive trading areas. Political restrictions, local labor rules, union requirements, security regulations, and port-specific obligations may also increase the Shipowner’s cost.

Where market conditions favor the Shipowner, the Shipowner may be able to negotiate that Charterers bear the Extra Insurance Premium (EIP) for risky port calls, war-risk areas, piracy zones, or other special trading exposures. In weaker Freight Markets, the Shipowner may have to absorb these costs in order to secure the Fixture. The commercial allocation of Extra Insurance Premiums (EIP) should therefore be addressed clearly during negotiations, because if the point is left uncertain, the additional cost may reduce the voyage result significantly.

The Shipbroker must also consider Taxes (T) that may apply to the intended trade. In some exporting or importing countries, a Freight Tax (FT) may be levied on the Gross Freight (GF) earned by the Shipowner. Other taxes, withholding charges, cargo-related levies, or local government assessments may also apply depending on the country, cargo, route, and contractual structure. These charges should be checked before fixing because they directly reduce the Shipowner’s net income. Reliable tax information should be obtained from Port Agents, local advisers, or recognized maritime sources before the Voyage Estimation is finalized.

4- Fourth Stage: Calculation of Income

In Voyage Estimation, the fourth stage is to calculate the income expected from the proposed employment. The principal income item is Gross Freight, meaning the total amount payable to the Shipowner for carrying the cargo. This figure is based on the Cargo Quantity Intake established during the earlier cargo measurement stage. Where Freight is fixed per metric ton, Gross Freight is calculated by multiplying the agreed cargo quantity by the agreed Freight rate per metric ton.

GROSS FREIGHT = AGREED QUANTITY OF CARGO × FREIGHT RATE PER MT OF CARGO

In some Fixtures, a Lump Sum Freight is agreed instead of a Freight rate per metric ton. In that case, the agreed Lump Sum becomes the Gross Freight, subject to any contractual adjustments. Lump Sum Freight can simplify the income calculation, but the Shipowner must still verify cargo quantity, loading obligations, cargo-handling terms, port time, and possible deductions or additions. A Lump Sum Freight that appears attractive may produce a weak daily result if the voyage is long, port costs are high, or cargo operations are slow.

Port time can also affect income through Demurrage (D) and Despatch Money (DM). If the ship is delayed beyond the agreed Laytime at the loading or discharging port, Charterers may be required to pay Demurrage (D) to the Shipowner. If cargo operations finish before the permitted Laytime expires, the Shipowner may have to pay or credit Despatch Money (DM) to Charterers, provided the Charter Party contains a Despatch provision. These items must be estimated realistically because they can increase or reduce the final Freight Revenue.

Demurrage (D) is usually agreed in the Charter Party as a fixed amount per day, with pro rata calculation for part of a day. Despatch Money (DM) is often fixed at half the Demurrage rate in dry bulk shipping, although this is not automatic and should be stated clearly. The Shipbroker should adjust the estimated Freight Revenue by adding expected Demurrage (D) or deducting expected Despatch Money (DM). If Charterers fail to provide the agreed full cargo quantity, Deadfreight (DF) may also become payable to the Shipowner and should be added to the income side of the calculation where appropriate.

In Voyage Estimation and Freight Calculation, Commission and Brokerage must be deducted from Gross Freight. Gross Freight may include Freight, Demurrage, Deadfreight, Over Freight, Ballast Bonus (BB), or other voyage income, depending on the Charter Party wording. These sums may all be subject to brokerage or commission unless the contract provides otherwise. The Shipbroker should therefore check carefully which income items are commissionable.

Brokerage: Brokerage is the fee or commission paid by the Shipowner to the Shipbroker for arranging or assisting with the Fixture. It is usually calculated as a percentage of Freight (F), Demurrage (D), or Hire (H), depending on the type of charter and the wording of the agreement.

Address Commission (ADCOM): Address Commission is a commission paid by the Shipowner to the Charterer, often at a rate such as 3.75%, although the exact percentage is negotiable. It is traditionally treated as a commercial allowance to the Charterer connected with the Charterer’s shipping operations and must be included as a deduction in the Voyage Estimation.

After deducting Brokerage, Address Commission, and any applicable Freight Tax (FT), the resulting figure is the Net Freight. Net Freight is the income figure that should be carried forward into the final voyage result, because it represents the amount remaining after the main income-side deductions have been applied.

NET FREIGHT = [GROSS FREIGHT + (DEMURRAGE + DEADFREIGHT + OVER FREIGHT + BALLAST BONUS (BB) – DESPATCH)] – COMMISSION – BROKERAGE – FREIGHT TAX (FT)

5- Fifth Stage: Final Result

In Freight Calculation, the fifth stage is to determine the final commercial result of the proposed voyage. At this point, the Shipbroker deducts the Total Voyage Expenses from the Net Freight. The balance is the Gross Voyage Result, which shows whether the proposed Voyage is expected to produce a profit or a loss before daily running costs and capital costs are considered.

GROSS VOYAGE RESULT = NET FREIGHT - TOTAL VOYAGE EXPENSES

After the Gross Voyage Result has been calculated, the Shipbroker divides that figure by the total number of days required to complete the Voyage. This produces the Gross Daily Result. The calculation should include the full commercial duration of the employment, including ballast days, laden sea days, port days, canal transit time, waiting time where reasonably expected, and any other time that prevents the ship from being available for the next employment. The Gross Daily Result is one of the most important figures in Freight Calculation because it allows Shipowners to compare different Voyage alternatives on a daily earning basis.

GROSS DAILY RESULT = GROSS VOYAGE RESULT ÷ DAYS OF THE VOYAGE

The Gross Daily Result is closely connected with the Time Charter Equivalent or TCE. In commercial practice, the TCE converts the expected result of a Voyage Charter into a daily figure comparable with Time Charter employment. This allows the Shipowner to decide whether a Voyage Charter is more attractive than a Time Charter alternative, a Trip Time Charter (TCT), a Contract of Affreightment (CoA), or another available employment opportunity.

To calculate the Net Daily Result, the ship’s Daily Running Costs are deducted from the Gross Daily Result. Daily Running Costs normally include manning, maintenance, stores, insurance, technical management, administration, lubricants, fresh water, repairs, and other operating expenses. The Net Daily Result therefore gives a clearer picture of the voyage’s contribution after ordinary ship-operating costs have been taken into account.

NET DAILY RESULT = GROSS DAILY RESULT - DAILY RUNNING COSTS

The Shipowner must then decide whether Capital Costs should also be included in the calculation. Capital Costs may include interest, loan repayment, depreciation, financing charges, and the Shipowner’s required return on investment. Some Shipowners calculate commercial performance only against operating expenses for short-term employment decisions, while others include both operating and capital costs in order to understand the full economic result. The important point is consistency. If one voyage is calculated with Capital Costs included and another is calculated without them, the comparison will be misleading.

If several Alternative Voyage Calculations for the same ship produce similar daily results, the Shipowner should examine the wider commercial consequences. A voyage with the same daily return but shorter duration may be preferable in a rising Freight Market because the ship becomes open sooner and may capture a stronger next Fixture. In a falling Freight Market, a longer employment may be more attractive because it protects the ship from immediate exposure to weaker rates. The duration of the voyage, the redelivery or next-open position, and the expected market direction must therefore be considered together with the numerical result.

Changes in the Freight Market during the voyage can materially affect the Shipowner’s strategy. If the market is strengthening, the Shipowner may prefer to complete the voyage quickly and enter the next Chartering Negotiation at improved levels. If the market is weakening, the Shipowner may seek longer coverage at rates reflecting current Spot Market conditions before the market declines further. Freight Calculation is therefore not only an accounting exercise; it is also a strategic tool for timing the ship’s employment.

Daily considerations for chartering include the ship’s Revenue Per Day compared to:

• The ship’s Total Costs Per Day, including voyage costs, operating costs, and capital costs where applicable;
• Current market levels and expected market direction;
• Alternative chartering opportunities available at the same time;
• Lay-up, sale, repositioning, or other strategic options.

Understanding the Time Charter Equivalent (TCE) of a proposed voyage is essential for Shipowners because it provides a practical daily benchmark. A Voyage Charter may show a large Gross Freight figure, but if the voyage is long, bunker costs are high, port delays are expected, or the ship is left in a weak next-position market, the daily result may be unattractive. The TCE brings these elements into a single daily figure that can be compared with alternative employment.

The TCE in Voyage Calculation may be expressed in several practical ways, depending on the company’s internal calculation method:

TIME CHARTER EQUIVALENT = GROSS FREIGHT (OR TOTAL VOYAGE INCOME) – VOYAGE COST

or:

TIME CHARTER EQUIVALENT = GROSS DAILY RESULT + % OF COMMISSIONS

or:

TIME CHARTER EQUIVALENT = TOTAL VOYAGE REVENUE PER DAY – VOYAGE COST PER DAY

The exact formula used should be applied consistently across all voyage comparisons. In practice, Shipowners usually focus on the daily result after deducting voyage expenses, because this shows what the ship earns per day before or after operating costs, depending on the chosen method. A consistent TCE calculation helps Shipowners compare different cargoes, routes, periods, markets, and charter types in a commercially meaningful way.

Special Freight Calculations

Consecutive Voyages and Contract of Affreightment (CoA) Freight Calculations

The principles used in Freight Calculation for Consecutive Voyages and a Contract of Affreightment (CoA) are broadly the same as those used for a single Voyage Estimation. However, these arrangements often cover longer periods and repeated cargo movements, which makes the calculation more complex. The Shipowner must consider not only the result of one voyage but also the combined performance of several voyages over time. Bunker prices, port costs, canal dues, exchange rates, cargo-handling expenses, Freight Market conditions, and ship positioning may all change during the Charter Period.

When assessing Consecutive Voyages or a Contract of Affreightment (CoA), the Shipowner must first decide how the ship can be traded most efficiently. The main objective is usually to reduce ballast time and increase laden employment. For example, the cargoes under a Contract of Affreightment (CoA) may be arranged as return voyages in a regular trade where Shipowners expect profitable cargoes on the reverse leg. Alternatively, the ship may perform one-way voyages with the return leg in Ballast, or the CoA cargoes may be used as intermediate employment between other commitments. Each pattern produces a different commercial result and must be examined carefully.

The calculation must also consider whether the ship will be dedicated to the Contract of Affreightment (CoA) or whether the Shipowner will combine CoA voyages with spot cargoes, Time Charter employment, or other market opportunities. If the ship is locked into a long sequence of voyages at a fixed Freight level, the Shipowner may lose the benefit of a rising market. If the market falls, the same arrangement may become valuable because it provides employment stability. For this reason, CoA Freight Calculations must include both operational assumptions and market expectations.

Sometimes, Freight Calculations do not concern a complete voyage from one open position to the next. Instead, the Shipowner may perform a Marginal Calculation. This occurs when a cargo opportunity appears while the ship is already in transit, either in Ballast or partly loaded, and the Shipowner must decide whether accepting that cargo improves the overall result.

A marginal cargo may require a limited route change, additional port call, or short time Deviation, while still broadly fitting the ship’s existing direction of travel. Such Way-Cargo may not be profitable if treated as a completely separate voyage. However, because the ship is already moving in a similar direction, the additional Freight may improve the economics of the overall voyage or reduce the loss of a Ballast passage. This is particularly relevant where the ship would otherwise sail empty or where the cargo can be carried without materially disturbing the ship’s main employment plan.

In a Marginal Calculation, the Shipowner does not usually allocate all voyage costs to the Way-Cargo. Instead, the calculation focuses on the additional costs created by accepting that cargo. These may include extra bunker consumption caused by the Extra Distance (Deviation), additional voyage time, extra port charges, agency fees, cargo-handling expenses, insurance premiums, documentation costs, and any delay to the ship’s main voyage or next employment. The additional Freight Revenue is then compared against these additional costs.

If the additional Freight Revenue, after deducting the extra costs, produces a positive supplemental Net Freight, the Way-Cargo may be commercially attractive. The Shipowner may then divide the supplemental result by the extra days required to perform the Deviation. This gives a daily surplus figure and helps determine whether the cargo improves the ship’s overall earning position. However, the decision should not be based only on the arithmetic result. The Shipowner must also consider cargo risk, port reliability, documentation, Laycan commitments, next employment, market positioning, and the possible effect on Charter Party obligations already undertaken.

Special Freight Calculations therefore require wider commercial judgment. Consecutive Voyages, Contracts of Affreightment (CoA), Way-Cargoes, and Marginal Calculations all involve more than a simple Freight-minus-cost formula. The Shipowner must evaluate the combined result, the effect on ship positioning, the reliability of future cargoes, the risk of market movement, and the opportunity cost of committing the ship. A carefully prepared calculation allows the Shipowner to use the ship more efficiently and avoid accepting employment that appears profitable in isolation but weakens the overall commercial result.

Time Charter Calculations

Time Charter calculations are generally less complex than Voyage Charter calculations because the main income figure is already known: the Time Charterer pays Shipowners an agreed Hire rate, usually expressed in dollars per day. Hire is normally payable in advance, often every 15 days, every 30 days, or monthly, depending on the Time Charter Party. In most cases, the Hire covers the commercial use of the ship, while the Time Charterer separately takes over and pays for Bunkers On Board (BOB) at delivery, and Shipowners take over and pay for bunkers remaining on board at redelivery.

Although the basic calculation may appear simple, Shipowners must still consider several commercial adjustments before deciding whether a Time Charter employment is attractive. The Time Charterer’s intended trade may increase Daily Operating Costs for Shipowners. For example, crew overtime, crew-change travel costs, higher maintenance expenses, increased spare-part consumption, additional survey requirements, or unusual operational demands may raise the real cost of performing the charter. Extra Insurance Premiums (EIP), war-risk costs, cargo-related equipment expenses, and special trading requirements may also need to be included in the calculation.

The cost of positioning the ship must also be considered. The Ballast Leg from the previous employment to the delivery place is usually for Shipowners’ account, as is the likely Ballast Leg from the redelivery place to the next commercial employment area. These positioning costs are not always visible in the daily Hire figure, but they can materially affect the true result of the Time Charter. Shipowners therefore adjust the required Time Charter Hire rate to reflect these costs. In some cases, the parties agree a separate Ballast Bonus (BB) to compensate Shipowners for positioning the ship before delivery or after redelivery.

Time Charter Hire may be expressed in different ways, but the starting point is normally the Gross Hire figure:

GROSS HIRE = TIME CHARTER HIRE PER DAY

Brokerage and Address Commission (ADCOM) are then deducted in a similar manner to Voyage Freight calculations. These deductions convert Gross Hire into Net Hire and show the daily amount retained by Shipowners after commercial commissions have been applied.

NET HIRE = GROSS HIRE – COMMISSION/BROKERAGE

To determine whether the Time Charter produces a real operating return, the estimator must deduct the ship’s Daily Running Costs from the Hire earned per day. Daily Running Costs may include crew wages, provisions, insurance, maintenance, repairs, stores, lubricating oil, technical management, administration, class-related expenses, and other ordinary operating expenses. If the Shipowner wishes to calculate a full economic result, capital costs such as interest, depreciation, loan amortization, and financing costs may also be included.

DAILY PROFIT = HIRE PER DAY – DAILY RUNNING COST

Bunker valuation can also affect the final Time Charter result. The Shipbroker must consider whether there is a difference between the Charter Party bunker price payable by Time Charterers at delivery and the bunker price applicable at redelivery. If bunker prices rise or fall sharply during the charter period, the bunker adjustment at redelivery may produce a significant gain or loss. The Charter Party should therefore state clearly the bunker quantities, grades, prices, valuation basis, and any minimum or maximum bunker quantities required at redelivery.

In the dry cargo market, Time Charter Hire is commonly quoted as a daily amount, such as “USD 20,000 per day.” For larger bulk carriers, longer periods, or more structured employment, Hire may also be quoted by reference to deadweight, for example “USD 5 per DWT per 30 days.” Index Linked Hires are also common for larger bulk carriers, especially where the Hire is tied to market benchmarks such as the Baltic Capesize Index (BCI). In reefer trades, Hire may be calculated by cubic capacity, for example as a rate per cubic foot bale per 30 days. In some cases, rates are based on the ship’s Summer Load Line Deadweight Capacity, regardless of the particular load-line zone in which the ship is trading.

Where the Hire is quoted per Summer DWT per month, the following formula may be used:

TIME CHARTER RATE PER SUMMER DWT PER MONTH ($) = GROSS DAILY HIRE ($ PER DAY) × 30.4375 DAYS (PER CALENDAR MONTH WHICH ALLOWS FOR THE EXTRA DAY EVERY FOURTH YEAR) ÷ SHIP’S SUMMER DWT

The same relationship can be reversed to convert a monthly DWT-based rate into a daily Hire amount:

GROSS DAILY HIRE ($ PER DAY) = TIME CHARTER RATE PER SUMMER DWT PER MONTH ($) × SHIP’S SUMMER DWT ÷ 30.4375 DAYS

These simplified Time Charter calculations allow Shipowners and Shipbrokers to compare Time Charter employment with Voyage Charter alternatives. A Voyage Charter may produce a high Gross Freight figure, but once Voyage Costs, ballast time, bunker consumption, commissions, port expenses, and the next employment position are considered, the daily result may be weaker than a Time Charter. Conversely, a Time Charter with a lower headline daily rate may be commercially attractive if it provides stable income, reduces market exposure, places voyage expenses on Charterers, and positions the ship favorably for future employment.

Reefer Freight Calculations

Reefer Freight Calculations follow many of the same principles used in dry cargo trades, but the operational and commercial priorities are different. Reefer ships are designed to carry temperature-controlled cargoes such as fruit, fish, meat, dairy products, pharmaceuticals, and other perishable commodities. Because these cargoes are sensitive to delay, temperature variation, ventilation, humidity, and handling conditions, Freight Calculation in reefer trades must consider not only weight, volume, distance, and port costs, but also cargo-care requirements and schedule reliability.

Marginal Freight Calculations are particularly common in reefer trades, similar to the calculations used in Liner Shipping. A reefer ship may have unused space during a Ballast Voyage or on a back-haul leg, creating an opportunity to carry additional cargo. However, reefer ships often operate under tight contractual schedules, seasonal programs, and cargo commitments. Even a small Deviation may be commercially impossible if it risks missing a loading window for perishable cargo, arriving late for a seasonal fruit program, or disrupting a long-term customer commitment.

In some trades, particularly across the Atlantic and Pacific, reefer Shipowners may combine traditional reefer carriage in one direction with a Liner Shipping-style service on the Back-Haul. This may involve carrying containers, palletized cargo, general cargo, or other non-reefer cargo where the ship has available space and the schedule permits. In such cases, the calculation becomes closer to a semi-container or general cargo operation. The Shipowner must compare the additional Freight earned with the cost of extra port calls, cargo-handling expenses, bunker consumption, schedule disruption, and any additional equipment or documentation required.

Reefer calculations must also account for the energy required to maintain cargo temperature. Refrigeration machinery, ventilation systems, generators, and monitoring equipment may increase fuel consumption, especially during long voyages or in warm climates. The calculation should therefore include not only the sea passage and port time but also the technical cost of preserving cargo quality. If the cargo requires special temperature control, pre-cooling, controlled atmosphere, or close monitoring, these requirements should be reflected in the Freight level and Charter Party terms.

The commercial value of reefer cargo may be high, but so is the risk. A late arrival, machinery failure, temperature deviation, power interruption, or improper cargo handling may lead to substantial cargo claims. Therefore, the Shipowner must ensure that the Freight calculation properly reflects the operational risk, insurance exposure, equipment condition, port reliability, and schedule discipline required by the trade. A cargo that appears profitable on a simple Freight-minus-cost basis may be unattractive if it creates excessive exposure to delay or cargo deterioration.

Liner Shipping Freight Calculations

In the Liner Shipping Business, Freight Calculations often involve marginal decisions rather than full voyage calculations. Liner ships usually operate within an established schedule, serving regular ports on a fixed or semi-fixed rotation. The main commercial question is often whether additional cargo can be accepted without disrupting the existing schedule, reducing service reliability, or displacing more profitable regular cargo. These additional cargoes may be described as Way-Cargo, inducement cargo, or special cargo bookings.

Marginal Calculations are especially useful where cargo is offered within or near the regular trading area but does not fit exactly into the normal service pattern. The cargo may require loading or discharging at a port outside the usual rotation, or at a port along the route that is not normally served by that particular ship. If the port can be reached by a minor Deviation and the ship has available space not reserved for regular bookings, the Shipowner or Liner Operator may calculate whether carrying the cargo produces a useful additional Freight contribution.

The purpose of the calculation is to determine whether the additional Freight Revenue covers the extra costs created by the cargo. These costs may include additional bunker consumption, port charges, pilotage, towage, agency fees, cargo-handling expenses, terminal costs, documentation, container positioning, reefer plug costs, lashing materials, stevedoring, and possible schedule recovery costs. If the cargo requires a Deviation, the calculation must also include the value of the extra time used and the effect on the ship’s next scheduled port.

When the prevailing Freight level is strong, accepting Way-Cargo at market rates may add materially to the Voyage Net Result. In a weak Freight Market, however, the additional cargo may not justify the extra time and cost. If the ship’s schedule is tight, the calculation must go beyond ordinary voyage expenses. The Liner Operator may need to consider whether schedule disruption will require chartering-in extra tonnage, transshipping cargo, paying delay claims, repositioning containers, or compensating regular customers. These indirect costs can eliminate the apparent profit from the additional cargo.

In a weak market, the Shipowner may also consider whether a low-paying regular cargo should be replaced by a more profitable Way-Cargo. This is another form of Marginal Calculation. The question is not whether the Way-Cargo is profitable in isolation, but whether it improves the total earning result compared with the cargo that would otherwise occupy the same space. The comparison should include Freight level, cargo-handling cost, weight, volume, equipment needs, schedule effect, customer relationship, and future commercial value.

Even where the Marginal Calculation shows a surplus, the Shipowner may still decide not to accept the cargo. Regular liner services depend on reliability, customer confidence, schedule discipline, and long-term cargo relationships. A one-time additional cargo may not be worth accepting if it risks damaging the operator’s reputation, delaying regular customers, disturbing contracted cargo flows, or creating operational complexity. For this reason, Liner Shipping Freight Calculations require both numerical analysis and commercial judgment.

In Liner Shipping, the best Freight Calculation is not simply the one that maximizes immediate revenue. It must also protect the schedule, maintain service quality, preserve customer relationships, and ensure that the ship’s available space is used in the most profitable and strategically sound way. Marginal cargoes can improve results, especially where space would otherwise sail empty, but they must be accepted only when the additional income justifies the additional cost, risk, and operational effect.

Tanker Freight Calculations

Tanker Freight Calculations follow the same broad commercial logic as Voyage Estimations for dry cargo ships: income must be compared with Voyage Costs, voyage duration, bunker consumption, port expenses, commissions, taxes, and the expected daily result. However, tanker calculations differ in important ways because tanker cargo handling, port time, pumping operations, heating requirements, tank cleaning, and the method of quoting Freight are not the same as in dry bulk or general cargo trades. In Tanker Charter Parties, it is usual to agree No Despatch Money (DM), and the allowed time for loading and discharging is commonly fixed at 72 hours for most tanker sizes, except for some very small ships or special trades.

The way tanker Freight Rates are expressed is also distinctive. Most Tanker Fixtures are quoted by reference to an international Freight scale known as the New Worldwide Tanker Nominal Freight Scale, usually called Worldscale (WS). Worldscale provides a common basis for quoting, comparing, and negotiating tanker spot rates across many routes. Without access to Worldscale information, it is extremely difficult to evaluate tanker employment accurately because the nominal route rates, assumptions, and adjustments form the working language of the tanker market.

Worldscale (WS)

Historical Background of Worldscale (WS)

The origins of tanker Freight Rate schedules can be traced to World War II. During the war, the British Government and later the United States Government requisitioned ships, including tankers, for wartime use. Shipowners were compensated on the basis of a daily Hire rate. In some cases, requisitioned tankers were made available to major oil companies for particular voyages, and Freight was paid to the government according to published scale rates. These scales were intended to produce a broadly consistent net daily return after allowing for port costs, bunker costs, canal dues, and other voyage expenses.

This wartime system later developed into tanker rate schedules designed to give Shipowners a uniform net daily revenue regardless of the route performed by the standard ship. Government control of shipping continued until 1948, but the tanker industry recognized the commercial usefulness of a structured scale system. Between 1952 and 1962, several non-governmental rate schedules were issued to support tanker trading, including “Scales Nos. 1, 2, and 3,” “Intascale” in London, and “ATRS” in New York.

In 1969, London and New York organizations worked together to combine Intascale and ATRS into the Worldwide Tanker Nominal Freight Scale, which became widely known by its codename, Worldscale. The word “nominal” originally reflected the fact that, under government-controlled shipping, the scale rates had been treated as actual applicable rates. Over time, the term came to mean that the published rates are theoretical benchmark rates, while actual Tanker Charter Rates are negotiated as percentages of those benchmark rates for a notional standard ship.

The introduction of Worldscale made it easier to express Tanker Spot Freight Rates. Instead of quoting rates as “plus” or “minus” percentages against a base rate, tanker rates are quoted as “points of scale.” For example, Worldscale 100 means 100 points or 100% of the published scale rate. Worldscale 250 means 250 points or 250% of the scale rate. Worldscale 30 means 30 points or 30% of the scale rate. The New Worldscale system introduced in 1989 remains the basis of modern tanker rate quotation.

Description, Rationale, and Use of Worldscale (WS)

Worldscale (WS) is a Nominal Freight Scale used for the carriage of crude oil and oil products in bulk by sea. It functions as an internationally recognized Freight Index System for tankers and provides a standardized method for calculating or quoting Freight on oil trades. The New Worldscale, introduced on 1 January 1989, replaced earlier tanker scale systems and is now commonly referred to simply as Worldscale.

Worldscale (WS) consists of Predefined Reference Tables that estimate Freight Rate levels for a notional standard tanker on approximately hundreds of thousands of round-trip tanker routes worldwide. The standard ship used for these calculations is a theoretical tanker with specific assumptions, including a deadweight capacity of 75,000 metric tons, an average speed of 14.5 knots, fuel consumption of 55 metric tons per day at sea, and a theoretical daily fixed cost of USD 12,000. This daily cost is not intended to represent the actual cost of operating every tanker. It is a theoretical figure used to maintain consistency in the scale calculation.

In tanker trading, several operating and trading assumptions apply to the standard ship for Freight Scale Calculations. These include:

1. Clearly identified, published distances for the trade routes included in the scale.
2. Fixed port time, commonly totaling four days, with 72 hours normally allowed for loading and discharging.
3. Voyage time calculated by reference to the ship’s assumed speed and the published distance for the route.
4. Bunker prices calculated as a monthly average for the relevant annual reference period, commonly from 1 October to 30 September of the previous year.
5. Port costs, canal transit charges, and other direct voyage expenses included and updated through the annual publication process.
6. Amendments to published rates during the year where the Worldscale Associations consider such changes necessary.

The Freight Rate for the standard ship on each route is shown as WS100, or W100, and is known as the Flat Rate or WS Flat. The Flat Rate is always expressed in US Dollars per metric ton. It forms the benchmark used for assessing, quoting, negotiating, and fixing tanker Freight Rates on a particular route. Actual tanker market levels and individual Tanker Fixtures are then expressed as a percentage of the Nominal Freight Rate (Flat Rate).

A fixture at WS100 means that the actual ship has been fixed at the same Freight level as the published Flat Rate for that route. Each WS100 figure is therefore a Freight Rate in US Dollars per metric ton of cargo for a specific round-trip voyage calculated on the assumptions of the standard ship. In simplified terms, the Flat Rate is the rate per metric ton that should generate total Voyage Revenue equal to the total voyage costs of the standard ship. WS100 therefore represents the breakeven level for the notional standard ship on that route under the Worldscale calculation method.

In practice, this breakeven concept applies directly only to the standard ship. Smaller ships may require a higher Worldscale equivalent to reach breakeven, while larger ships may achieve breakeven at a lower equivalent because of economies of scale. This is why Worldscale points alone do not always tell the full commercial story. The actual result depends on the ship’s size, speed, bunker consumption, port costs, cargo quantity, and voyage pattern.

An example shows how Worldscale (WS) works. If the Worldscale tables show a Flat Rate of USD 20.00 per metric ton for a crude oil voyage from the Arabian Gulf to Western Europe, and the tanker is fixed at WS60, the actual Freight rate is 60% of USD 20.00. The actual rate is therefore USD 12.00 per metric ton. The purpose of Worldscale is to provide a standardized reference point so that alternative tanker voyages can be compared more easily and negotiated with a common market language.

The principle behind Worldscale is that WS100 should produce the same net return per day for the standard ship, regardless of the route performed. This makes Worldscale a useful chartering tool because it offers consistency and flexibility when comparing employment alternatives. However, Shipowners must still convert Worldscale rates into actual voyage results for their own ships. A ship fixed at WS75 on one route is not necessarily earning less than another ship fixed at WS80 on another route, because voyage costs, bunker consumption, port charges, canal dues, cargo quantity, and daily running costs may differ significantly.

For this reason, Tanker Owners often prepare detailed Voyage Calculations for the ships and trades they most frequently operate. By converting different Worldscale levels into daily earnings, they can assess whether an offered Fixture is attractive when compared with alternative employments. This allows Tanker Owners to maintain internal tables showing the approximate daily result for their ships at different Worldscale rates and on different trade routes.

Although crude oil and product tanker Fixtures are commonly reported in Worldscale (WS) Terms, not all liquid cargo markets use Worldscale. Spot rates for gas carriers, chemical tankers, and certain specialized liquid cargo ships are often quoted directly in US Dollars per metric ton, per cubic meter, per cubic foot, or another agreed unit. The correct pricing method depends on the cargo, ship type, trade route, and market custom.

Worldscale (WS) Publications are revised annually on 1 January. These revisions reflect changes in tanker operating and trading costs, including bunker prices, port charges, canal expenses, currency exchange rates, and other cost components. The information is available by subscription to Tanker Owners, Tanker Managers, oil companies, Shipbrokers, Shippers, traders, and other participants in the tanker market.

Worldscale (WS) is a non-profit organization. It was established corporately in 1962 and renamed in 1969. In its modern form, based on the standard tanker concept introduced in 1989, Worldscale is jointly sponsored and published by Worldscale Association (London) Limited and Worldscale Association (NYC) Inc. The organization is managed by shipping professionals and directors from leading shipbroking firms in London and New York. Its role is not to set actual market rates, but to provide the neutral scale system through which tanker market rates can be expressed and compared.

Worldscale (WS) Practical Tips

In addition to the basic Worldscale principles already explained, Shipbrokers and Tanker Owners must understand several practical details that affect how Worldscale (WS) Calculations are applied in real tanker chartering. Worldscale is not merely a list of theoretical rates. It is a working system that combines route assumptions, port costs, canal expenses, differentials, bunker assumptions, and voyage-time calculations into a standard framework for quoting and comparing tanker Freight.

• Published Flat Rates apply to specific named loading and discharging ports on round voyage assumptions. They are not normally quoted for broad port ranges in the same way as many dry cargo fixtures. Rates for combinations of ports can be calculated, including voyages involving several loading ports and several discharging ports. In practice, Worldscale can calculate rates for combinations involving up to five loading ports and ten discharging ports, while more complicated voyage structures may require a special calculation request.
• The Worldscale system calculates and publishes what is considered the most economical route for each trade, taking into account distance, canal dues, pilotage charges, and other route-related costs. The shortest nautical route is not always the cheapest commercial route. A route that saves distance may still be more expensive if it involves substantial canal tolls, waiting time, pilotage, tug assistance, or other transit charges. For this reason, Worldscale uses route indicators in the Schedule and in rate quotations.
  • C: via Cape of Good Hope, laden and in ballast
  • CS: via Cape of Good Hope laden, Suez Canal in ballast
  • S: via Suez Canal, laden and in ballast
  • P: via Panama Canal, laden and in ballast
  • CP: via Cape of Good Hope laden, Panama Canal in ballast
  • H: via Cape Horn, laden and in ballast
  • CH: via Cape of Good Hope laden and in ballast, or Cape Horn laden and in ballast
• In the Worldscale rate tables, voyages are normally arranged alphabetically by discharge port. To identify the applicable rate, the user first locates the discharge port shown in bold capital letters and then finds the relevant loading port beneath it. The table then provides the USD per metric ton Flat Rate and the relevant distance in nautical miles. Correct reading of the table is important because a wrong port, wrong route indicator, or wrong differential can materially distort the Freight calculation.
• Book Notes appear beside loading and discharging ports in the Worldscale tables. These notes are not decorative or optional. They may identify additions, differentials, special conditions, or adjustments that must be applied to the published Flat Rate. A Tanker Broker who ignores Book Notes may calculate a rate that is commercially inaccurate or inconsistent with the Worldscale basis used by the market.
• Additions apply to certain geographical areas and trades, including voyages loading within the Arabian Gulf, Black Sea, and Lake Maracaibo. The relevant addition rates are normally set out separately in the blue section of the Worldscale book. These additions simplify the scale by avoiding the need to publish a separate complete rate for every possible port combination. For example, a rate from the Black Sea may be calculated first to Uskudar in Turkey, with the remaining route calculated from Uskudar onward.
• Differentials are listed in the pink section of the Worldscale publication and are numbered sequentially, such as D-1, D-2, and so on. Differentials deal with costs that are not included in the ordinary Worldscale Flat Rate, or costs that vary according to cargo type, terminal, cargo quantity, route, or other special circumstances. They are important because they adjust the Flat Rate to reflect real cost differences that would otherwise be hidden inside a standard route figure.
  • Fixed Differentials: Fixed Differentials may apply to costs such as Panama Canal or Suez Canal dues where those expenses are handled separately from the ordinary Flat Rate calculation. In some cases, canal dues may be paid directly by Charterers to the canal authorities or included in Freight as a fixed differential. These fixed differentials are not multiplied by the Worldscale percentage agreed in the Fixture. Instead, they are calculated according to the specific terms applicable to the differential, often by reference to the actual cargo quantity.
  • Variable Differentials: Variable Differentials apply where costs differ within the same port or port area, especially where one terminal is more expensive than another. These differentials may add to or deduct from the Flat Rate in USD terms. Unlike fixed differentials, the agreed Worldscale percentage in the Fixture is normally applied to variable differentials. They are especially common in ports with Single Buoy Mooring (SBM) facilities, offshore terminals, or terminal arrangements where cost levels differ materially from conventional berths.
• Annual Bunker Prices and Consumption Rates: Worldscale calculations are based on standard bunker assumptions. Standard 380 CST fuel is generally used unless low sulphur fuel is required by local law, emission control rules, or port requirements for part of the voyage or for in-port consumption. Where low sulphur fuel requirements apply, the additional cost may be included in the Worldscale rate through fixed differentials per voyage mile or built into the Flat Rate, depending on the applicable Worldscale treatment. Tanker Owners must still compare Worldscale assumptions with their own ship’s actual consumption because real bunker performance can differ substantially from the standard ship.
• Voyage and Port Time Calculations: Voyage time and port time are multiplied by the fixed daily Hire element used for the notional standard ship. This figure represents the theoretical operating and capital cost of the standard ship in the Worldscale model. In practice, Tanker Owners must know the actual daily cost of their own ships in order to assess whether a given Worldscale level is profitable. A Fixture at an attractive Worldscale percentage may still produce a weak result if the actual ship consumes more bunkers, has higher operating costs, or performs a route less efficiently than the standard assumptions.

Worldscale (WS) Practical Guidelines

Port costs connected with the standard ship are treated within the Worldscale system in different ways. The purpose is to produce a practical Flat Rate that reflects ordinary Shipowner-responsible expenses while separating or excluding costs that are special, voyage-specific, or for Charterers’ account. Broadly, port costs and voyage-related charges are treated under the following categories:

• Normal Costs: These are ordinary port and voyage costs included in the Flat Rate as standard allowances.
• Voyage Costs: These include major route-related costs, such as Panama Canal and Suez Canal tolls, where separate differential treatment may be required because the amounts are too significant or too route-specific to treat as ordinary port costs.
• Charterers’ Account: These are costs allocated directly to Charterers and are not included in the Flat Rate. If Shipowners pay them in the first instance, Shipowners should be entitled to reimbursement from Charterers according to the Worldscale terms and the Charter Party wording.
• Fixed or Variable Differentials: These are separate adjustments applied according to the nature of the relevant cost and the method by which it is charged.
• Exclusions: Certain costs are not included in the Worldscale calculation at all and must be dealt with separately in the Fixture or Charter Party.

The objective of the Worldscale system is to include realistic allowances for the port costs that are normally for Shipowners’ account. These costs may include light dues, pilotage, towage, terminal fees, mooring and unmooring charges, standby tug and launch fees, watchmen, conservancy dues, harbour dues, port dues, quay dues, berth hire, tonnage dues, wharfage, dockage, berthage, launch hire, port clearance, quarantine, free pratique, customs attendance, customs overtime, sundries, petties, agency fees, and ISPS-related charges. Since these costs vary widely between ports, the Worldscale system attempts to standardize them in a way that allows tanker rates to be compared across routes.

Charterers’ Account items are identified by country or by voyage-specific circumstances. These items are not included in the Flat Rate because they are not intended to be borne by Shipowners under the standard Worldscale allocation. Where Shipowners incur such expenses, the Charter Party should preserve the right to recover them from Charterers. A clear understanding of Charterers’ Account items is important during Fixture negotiations because otherwise a cost that should have been passed to Charterers may reduce Shipowners’ net result.

The Worldscale (WS) System is based on a standard ship of 75,000 DWT, which is intended to represent a practical reference size in tanker trading. Fleet statistics are periodically reviewed to ensure that the standard remains commercially meaningful. However, Worldscale does not include additional costs or efficiencies arising from ships that differ from the standard size. Therefore, Tanker Owners and Charterers must negotiate or calculate for themselves the effect of using smaller or larger ships, different cargo quantities, different fuel consumption, different port performance, or different operating cost structures.

Freight Calculation under Worldscale can be summarized as follows:

Worldscale Flat Rate, including any applicable additions, multiplied by the Worldscale Equivalent and the Cargo Quantity, plus any applicable Variable Differentials multiplied by the Worldscale Equivalent and Cargo Quantity, plus any Fixed Differential calculated according to the specific terms of the current Worldscale publication, plus any supplementary Worldscale adjustments required by the particular case.

In practical form, this can be expressed as:

WORLD SCALE FREIGHT = [FLAT RATE + ADDITIONS + VARIABLE DIFFERENTIALS] × WS PERCENTAGE × CARGO QUANTITY + FIXED DIFFERENTIALS + SUPPLEMENTARY ADJUSTMENTS

This formula must be applied carefully because not every item is treated in the same way. Some items are multiplied by the agreed Worldscale percentage, while others are fixed and are not affected by the Worldscale percentage. A Shipbroker must therefore identify whether each applicable adjustment is an addition, a variable differential, a fixed differential, a Charterers’ Account item, or an excluded item.

Worldscale does not make allowance for every possible cost that may arise during a tanker voyage. No provision is made for Freight Tax or Income Tax. Additional marine insurance costs for trading in certain areas may also fall outside the standard calculation. The system does not automatically allocate Deviation expenses, Deballasting expenses, special waiting time, special security measures, or other unusual costs unless the relevant Worldscale provisions or Charter Party terms expressly deal with them. These items must therefore be considered separately during negotiations and included in the Fixture recap where necessary.

For Tanker Owners, Worldscale is a powerful tool, but it is not a substitute for proper Voyage Estimation. The published Flat Rate gives a common market reference, yet the actual commercial result depends on the real ship, real cargo quantity, real bunker consumption, actual port expenses, insurance exposure, canal arrangements, weather, waiting time, and the Shipowner’s own daily cost. A well-prepared Tanker Freight Calculation therefore combines the Worldscale framework with ship-specific and voyage-specific analysis.

Worldscale (WS) Book Structure and Contents

Every Worldscale (WS) subscriber receives an annual Worldscale Book, which sets out the reference framework used for tanker Freight calculations, route comparisons, rate quotations, and chartering negotiations. The book is not merely a list of Freight rates. It contains explanatory material, terms, port lists, flat rates, differentials, additions, and practical guidance that allow Shipowners, Charterers, oil companies, traders, and Shipbrokers to calculate tanker Freight on a consistent basis.

• Preamble Part A: Explanatory Notes This section contains definitions, general explanations, the basis of calculation, route policies, distance assumptions, port-cost assessment methods, and revision procedures. It explains how the Worldscale system is constructed and how the published figures should be interpreted.
• Preamble Part B: Terms and Conditions This part includes the effective date of the scale, Laytime allowances, port and terminal combinations, and items that are expressly for Charterers’ account. It is important because it identifies the commercial and contractual assumptions behind the published rates.
• Preamble Part C: Table of Demurrage Rates This section provides demurrage rates applicable under the Worldscale system. These rates vary according to ship size and are used where the parties have not agreed a separate fixed demurrage amount in the Charter Party.
• Preamble Part D: List of Ports This part lists ports and transshipment areas alphabetically by port name, country, and geographical area. It helps users identify the correct port references before applying the relevant route rates, additions, or differentials.
• Schedule of Flat Rates (WS100) This is the central part of the Worldscale Book. It contains the basic calculated Freight rates for the standard ship on specific tanker routes. These Flat Rates represent WS100 and form the benchmark from which actual market rates are negotiated.
• Fixed Rate Differentials (Worldscale percentage does not apply) This section deals with costs such as canal transit dues and other high-cost items that may depend on ship size, cargo size, route, or special circumstances. Because these items are fixed differentials, the agreed Worldscale percentage is not applied to them unless the Worldscale terms expressly provide otherwise.
• Variable Rate Differentials (Worldscale percentage applies) These differentials adjust the Flat Rate where costs vary between terminals or berths within the same port. Since they are variable differentials, the agreed Worldscale percentage normally applies to them. They are particularly relevant where a port has different terminal structures, offshore loading points, Single Buoy Mooring (SBM) facilities, or cost variations that must be reflected in the Freight calculation.
• Additions This section defines waypoints and additional rate elements within major loading areas such as the Arabian Gulf, Black Sea, and Lake Maracaibo. Additions simplify route calculations and make it easier to calculate rates for complex trades without publishing a separate complete rate for every possible port combination.

WSHTC or WHTC (Worldscale Hours Terms and Conditions) refers to the incorporation of current Worldscale (WS) Terms into a tanker Charter Party. When this expression is used, the parties generally intend the applicable Worldscale terms, including relevant time and cost provisions, to apply to the Fixture unless expressly amended by the Charter Party.

Worldscale (WS) Laytime, Demurrage, Despatch, Laycan

Worldscale (WS) also deals with Demurrage and related time-cost elements. Different ship sizes have different Demurrage Rates under the Worldscale system, and those rates may be adjusted according to the Worldscale Freight level agreed between Shipowners and Charterers. In modern tanker practice, however, many Shipowners and Charterers prefer to agree a fixed daily Demurrage rate in US Dollars rather than relying entirely on the Worldscale demurrage table. This gives both parties a clearer financial figure during negotiations and reduces uncertainty in claims handling.

Under Worldscale (WS) Terms, Demurrage normally begins after the expiry of the standard 72 hours of Laytime allowed for loading and discharging. This Laytime is usually calculated on a SHINC (Sundays and Holidays included) basis, meaning that Sundays and holidays count unless the Charter Party provides otherwise. This differs from many dry cargo trades, where working-time exceptions and Laytime wording can vary widely. In tanker chartering, the 72-hour standard gives the parties a more uniform starting point for time calculations, although congestion, terminal delays, documentation, pumping performance, weather, inspections, and port restrictions may still create disputes.

Despatch Money (DM) is not awarded in the tanker industry as a normal practice. This is an important distinction from many dry bulk Fixtures, where Despatch Money (DM) may be payable if Charterers complete cargo operations before the end of Laytime. In tanker trades, early completion normally benefits both parties operationally, but it does not usually create a Despatch payment obligation from Shipowners to Charterers unless the Charter Party contains unusual wording.

Laydays and Cancelling Dates in tanker trades are generally much tighter than in many dry cargo trades. In some cases, the Laycan window may be only two or three days. Oil companies, traders, refineries, and terminals often work with strict cargo programs, storage constraints, pipeline schedules, blending requirements, refinery intake schedules, and berth availability windows. For this reason, Charterers may require the ship to arrive at the loading port within a very narrow time range. In some modern tanker Fixtures, Shipowners may be expected to present the ship within a 24-hour window because cargo availability and terminal planning leave little flexibility.

If a full cargo quantity is not available, Charterers may agree to provide a minimum quantity with an option to load additional cargo up to the ship’s capacity. Cargo loaded above the agreed minimum quantity is often referred to as “Overage”. In tanker practice, Overage may be charged at 50% of the Charter Party Freight Rate, although the exact treatment must always be checked against the Fixture recap and Charter Party wording. Overage provisions are commercially important because they allow Charterers flexibility in cargo programming while giving Shipowners compensation for carrying additional cargo beyond the minimum contractual quantity.

Payment terms also require careful attention. In many Voyage Charters, Freight is payable after completion of discharge, but Shipowners may demand stronger payment protection where Charterers are not well known or where credit risk is a concern. Charterers without strong financial standing may be required to pay Freight Before Breaking Bulk (BBB), provide a bank guarantee, arrange a letter of credit, or offer another form of security. This is similar to credit-protection practice in dry cargo shipping, where Shipowners may seek to reduce the risk of delivering cargo without receiving payment.

Worldscale (WS) Time Charter

Worldscale (WS) is mainly used for Tanker Voyage Charters, Consecutive Voyage Charters, and Contract of Affreightment (COA) arrangements. These forms of employment depend heavily on route-based Freight calculations, and Worldscale provides the common language for quoting tanker spot rates. Time Charters, by contrast, are usually structured differently. In a Tanker Time Charter, the Charterer hires the ship for a defined period or trip and pays Hire in US Dollars per day, in much the same way as in dry cargo Time Chartering.

Oil companies, commodity traders, refiners, and major energy groups frequently use Tanker Time Charters to secure tonnage for longer-term requirements. This allows them to manage exposure to a volatile spot market, control transport availability, support refinery supply programs, and ensure access to suitable ships for repeated cargo movements. Period Charters can also help Charterers manage operational continuity where cargo flows are predictable but spot tanker rates are uncertain.

As in Voyage Chartering, many major oil companies use their own Standard Time Charter Party forms for tanker employment. These forms often contain detailed provisions dealing with vetting, oil major approvals, cargo compatibility, pumping performance, tank cleaning, cargo heating, inert gas systems, pollution prevention, sanctions, war risks, trading limits, insurance, and operational reporting. Tanker Time Charter forms therefore tend to be more specialized than many dry cargo Time Charter forms because of the regulatory and technical demands of oil and product transportation.

Worldscale (WS) is not usually applied directly to Tanker Time Charters. The normal Time Charter structure is based on a daily Hire rate in US Dollars, with the Charterer paying bunkers and voyage expenses while Shipowners remain responsible for operating costs and technical management. However, Worldscale may become relevant if the Time Charter rate is linked to Spot Market Freight Indices, selected tanker Routes, or earnings formulas based on market movements. In such cases, the parties must define the reference route, the index source, the calculation period, the adjustment mechanism, and the method for converting Worldscale or spot market levels into Hire.

For Shipowners and Charterers, the key point is that Worldscale remains a voyage-based tanker pricing tool. It is invaluable for comparing spot tanker employment, evaluating route economics, and negotiating Tanker Voyage Charters. In Time Chartering, however, the focus shifts from route-specific Freight to daily Hire, ship performance, trading flexibility, operating costs, vetting status, and the commercial value of securing the ship for a period. Clear drafting is therefore essential if the parties wish to connect a Tanker Time Charter rate to Worldscale-based market indicators.