Bulk Carrier Ships

Bulk Carrier Ships form the backbone of the world's dry cargo trades. They move the raw materials that feed steel mills, power stations, cement plants, grain processors, fertilizer producers, construction industries, and manufacturing supply chains. The dry cargo fleet ranges from small coastal ships trading between nearby ports to enormous ore carriers designed to move very large parcels of iron ore over long ocean routes.

Modern dry cargo ships are no longer simple steel boxes with engines. They are increasingly fuel-efficient, cargo-friendly, environmentally regulated, and designed around port productivity. Their cargo spaces, hatch covers, ballast systems, hull forms, main engines, cargo gear, and safety systems are developed to reduce port time, protect cargo, lower unit cost, and satisfy Charterers, terminals, classification societies, insurers, and regulators.

Some dry cargo ships are highly specialised and are intended for one principal cargo or one particular trade. Others are deliberately flexible and are capable of carrying many cargoes, including bulk commodities, bagged goods, steel products, project cargo, forest products, containers, or a mixture of cargo parcels. The commercial value of a dry cargo ship depends not only on its deadweight, but also on its cargo spaces, gear, draft, speed, bunker consumption, hatch dimensions, hold strength, cargo fittings, and the number of ports in which it can operate.

This article explains the main dry cargo ship types, their size ranges, basic design features, cargo suitability, cargo gear, special equipment, and the practical reasons why different ships are used in different trades.

Bulk Carrier Ship Types

Dry cargo ship design has developed around the need to carry a wide variety of commodities efficiently. Some ships are pure bulk carriers, built mainly for grain, coal, ore, bauxite, fertilizers, salt, petcoke, and similar commodities. Some ships are Multi-Purpose Ships (MPP), designed to carry break-bulk cargo, project cargo, bulk cargo, and containers. Some ships are container ships or Ro-Ro ships, built around fast cargo handling and scheduled services. Others are specialised ships built for timber, cement, livestock, refrigerated cargo, heavy lifts, barges, or combined wet and dry cargo trades.

Several ship designs overlap between markets. A modern multi-purpose ship may carry containers on one voyage, bulk cargo on another voyage, and bagged or baled cargo on a later voyage. A heavy-lift ship may enter a project cargo trade that once belonged to specialised heavy-lift operators. A log carrier may also carry certain conventional bulk cargoes when the market allows. This flexibility is commercially valuable because it reduces ballast time and gives the Shipowner more employment options.

Since 1945, the design philosophy of dry cargo ships has changed significantly. Earlier ships required more manual labour and were less efficient in cargo handling. Modern ships are designed to be cargo-friendly, meaning that hatch openings, hold shapes, gear arrangements, tanktop strength, cargo securing fittings, and access arrangements are designed to speed loading and discharge while reducing cargo damage. At the same time, higher bunker costs and environmental rules have pushed naval architects toward improved hull forms, better propellers, more efficient main engines, and lower-emission performance.

Modern ports also shape ship design. Deepwater terminals with high-capacity loaders, grab cranes, gantry cranes, conveyors, and shore unloaders require ships with open, accessible hatch arrangements. Ships must be able to load and discharge quickly because port time is expensive. The larger the ship, the more important it becomes to combine economies of scale at sea with efficient cargo handling in port.

Bulk Carrier Ship Types are divided into:

1- Bulk Carriers

2- General Cargo Ships

3- Containerships

4- Ro-Ro Ships

5- Specialised Ships

6- Short-Sea Ships (Coaster Bulk Carrier Ships)

1- Bulk Carriers

Bulk carriers are ships designed mainly to carry dry bulk cargoes in loose form. Their cargo holds are arranged to receive cargo directly from shore loaders, conveyor systems, grabs, chutes, spouts, or pneumatic equipment. The most common cargoes include iron ore, coal, grain, bauxite, alumina, fertilizers, cement clinker, salt, sugar, sulphur, scrap, petcoke, and other mineral or agricultural products.

Modern bulk carriers are normally built with double hull or double-side features depending on size, regulation, and design. Double-side arrangements improve cargo protection and reduce the problem of cargo lodging between side frames. They also reduce mechanical damage from cargo grabs striking internal frames and shell plating. Smoother hold surfaces make discharge easier and reduce hold cleaning time before the next cargo.

The reintroduction of the forecastle on many bulk carriers improves forward protection in heavy weather and gives better working arrangements at the bow. Modern hatch covers, improved ballast systems, stronger tanktops, and more efficient hold geometry also contribute to safer and faster cargo operations.

Most modern deepsea bulk carriers up to Panamax or Kamsarmax size may be fitted with cranes, especially in the Handymax, Supramax, and Ultramax segments. Larger bulk carriers such as Capesize, Newcastlemax, Very Large Ore Carriers (VLOC), Ultra Large Ore Carriers (ULOC), and Valemax types are usually Gearless because they trade between major terminals equipped with high-capacity shore gear. Small coasters may also be gearless if they operate between ports with appropriate shore equipment.

Bulk Carrier Ship Sizes

Classification Size (DWT) Typical Length

Coaster Bulk Carriers: 1,000 - 10,000 DWT

Handysize Bulk Carriers: 10,000 - 39,999 DWT, generally below about 160 meters

Handymax Bulk Carriers: 40,000 - 59,999 DWT, generally below about 190 meters

Supramax Bulk Carriers: about 50,000 - 60,000 DWT

Ultramax Bulk Carriers: about 60,000 - 65,000 DWT

Panamax Bulk Carriers: about 60,000 - 99,999 DWT, traditionally below about 240 meters in many older descriptions

Kamsarmax Bulk Carriers: about 80,000 - 82,000 DWT

New Panamax Bulk Carriers: up to about 120,000 DWT depending on design and canal restrictions

Capesize Bulk Carriers: about 100,000 - 199,999 DWT, often up to around 300 meters in length

Newcastlemax Bulk Carriers: about 200,000 - 210,000 DWT

Very Large Ore Carriers (VLOC): about 200,000 - 299,999 DWT

Ultra Large Ore Carriers (ULOC): about 300,000 - 399,999 DWT

Chinamax (Valemax): over 400,000 DWT

Coaster Bulk Carriers (1,000-10,000 DWT): Coaster Bulk Carriers operate mainly in coastal, domestic, short-sea, river, island, and regional trades. Their shallow drafts allow them to reach smaller ports, river berths, and terminals where deepsea ships cannot enter. Coasters are important in countries with long coastlines, island networks, inland waterways, or small industrial ports. They frequently carry aggregates, cement, grain, fertilizers, salt, steel, coal, and other regional cargoes.

Handysize Bulk Carriers (10,000-39,999 DWT): Handysize Bulk Carriers are among the most versatile ships in the dry bulk fleet. They can trade deepsea but still enter many smaller ports with draft, beam, length, or cargo gear limitations. Many Handysize ships are geared, which allows them to load or discharge where shore cranes are limited or unavailable. They are commonly used for grain, fertilizers, minor bulks, steel products, logs, bagged cargoes, and mixed parcels.

Handymax Bulk Carriers (40,000-59,999 DWT): Handymax Bulk Carriers offer more cargo capacity than Handysize ships while retaining good port flexibility. They are well suited for trades where cargo parcels are larger but terminals are not capable of handling Panamax or larger tonnage. Many Handymax ships have five cargo holds and four cranes, often around 25 to 35 tonnes SWL (Safe Working Load), although designs vary.

Panamax Bulk Carriers (60,000-99,999 DWT): Panamax Bulk Carriers were originally developed around the old Panama Canal lock dimensions. They became a standard workhorse for grain, coal, and certain mineral trades. Traditional Panamax beam was limited by the old locks, giving these ships a distinctive design. Many Panamax ships have seven cargo holds and are commonly gearless. They remain important in coal and grain trading, although Kamsarmax and New Panamax designs have taken a larger role in many modern trades.

Panamax and Neo Panamax Dimensions:

Panamax: about 294.13 m length, 32.31 m beam, and about 12.04 m draft under traditional lock limitations.

Neo Panamax: about 366 m length, 51.25 m beam, and about 15.2 m draft under the expanded lock system.

Capesize Bulk Carriers (100,000-199,999 DWT): Capesize Bulk Carriers are too large for many traditional canal and port restrictions and are therefore associated with deepwater trades. The name reflects the historical need to sail around major capes such as the Cape of Good Hope or Cape Horn when canal passage was not possible or economical. Capesize ships mainly carry iron ore and coal, especially on long-haul routes between major mining regions and industrial consumers. They need deepwater terminals, strong loaders, high discharge capacity, and large cargo parcels.

Very Large Ore Carriers (VLOC) (200,000-299,999 DWT) / Ultra Large Ore Carriers (ULOC) (300,000-399,999 DWT): VLOC and ULOC ships are specialised large ore carriers, mainly employed in major iron ore trades. Their enormous cargo capacity reduces unit transport cost where cargo volumes and terminal infrastructure justify their use. Because of their size, only a limited number of ports can receive them. They require deep draft, long berths, high-capacity loaders and unloaders, strong mooring arrangements, and efficient cargo logistics ashore.

Bulk Carrier Ship Sub-Classes

Supramax Bulk Carriers (50,000-60,000 DWT): Supramax Bulk Carriers are highly popular because they combine useful cargo capacity with onboard cranes and broad port access. Most Supramax ships have five cargo holds and four cranes, often around 30 tonnes SWL (Safe Working Load). They can serve many ports lacking sophisticated shore gear and are widely used for minor bulks, coal, grain, fertilizers, steel, petcoke, salt, cement, and project cargo.

Ultramax Bulk Carriers (60,000-65,000 DWT): Ultramax Bulk Carriers are an enlarged development of the Supramax concept. They offer greater cargo intake and improved fuel efficiency while retaining cranes and strong port flexibility. Ultramax ships are attractive to Charterers and Shipowners because they can lift more cargo than a Supramax without losing too much trading range. They are often viewed as the modern upgrade of the Handymax and Supramax categories.

New Panamax Bulk Carriers (Neopanamax Bulk Carriers): New Panamax or Neopanamax Bulk Carriers are designed around the expanded Panama Canal lock dimensions. The expanded canal allows much larger ships than the old Panamax limit, subject to draft, beam, air draft, and operational restrictions. Neopanamax designs can offer greater cargo lift while retaining canal flexibility for selected routes.

Kamsarmax Bulk Carriers: Kamsarmax Bulk Carriers are enlarged Panamax-type ships of about 82,000 DWT. Their name comes from Port Kamsar in Guinea, a major bauxite export terminal. The design reflects the maximum practical length and size suitable for that trade while retaining broad Panamax-style trading flexibility. Kamsarmax ships are now widely used in coal, grain, bauxite, and other dry bulk trades.

Newcastlemax Bulk Carriers: Newcastlemax Bulk Carriers are large Capesize-type ships designed around the dimensional limits associated with the coal terminal at Newcastle, Australia. They are typically around 200,000 to 210,000 DWT, with large beam and length. Newcastlemax ships mainly trade in iron ore and coal between Australia, Brazil, and Asia, although actual employment depends on terminal compatibility and freight markets.

Setouchmax Bulk Carriers: Setouchmax Bulk Carriers are designed for the maximum practical size able to trade into suitable ports of the Seto Inland Sea in Japan. These ships are large Capesize-type bulk carriers with dimensions suited to Japanese industrial import terminals. They usually carry iron ore and coal for steel mills and power utilities. Their design demonstrates how regional geography and port limitations shape ship size.

Seawaymax Bulk Carriers (Lake-Fitted Bulk Carriers): Seawaymax Bulk Carriers are designed around the St. Lawrence Seaway and Great Lakes lock restrictions. They have limited length, beam, and draft compared with ocean-going bulk carriers. Lake-Fitted Bulk Carriers may also include special features for Great Lakes trading, such as shallow-draft capability, strong manoeuvrability, and equipment suited to seasonal conditions, icing, restricted channels, and specialised unloading systems.

Lake-Fitted Bulk Carriers are shaped by the geography of North America’s inland waterway system. They may carry iron ore, coal, grain, salt, aggregates, and other industrial cargoes. Typical maximum dimensions are around 225.5 meters length, 23.8 meters beam, and about 8 meters draft, although exact limits depend on lock rules and water levels. Their design is a strong example of engineering adapted to a specific trading environment.

Malaccamax Bulk Carriers: Malaccamax Bulk Carriers refer to the largest practical ships able to pass through the Strait of Malacca. The limiting factor is mainly draft rather than canal lock dimensions. Malaccamax designs are important because the Strait of Malacca is a critical route between the Indian Ocean and East Asia. Ships approaching this limit may be around 300,000 DWT or more, depending on design and operating conditions.

Dunkirkmax Bulk Carriers: Dunkirkmax Bulk Carriers are designed around the maximum practical dimensions for certain facilities at the Port of Dunkirk in France. Their approximate capacity may be around 175,000 DWT, with dimensions suited to the port’s draft, beam, and berth constraints. Like other “max” ship classes, the name reflects a specific port limitation rather than a universal regulatory category.

Bulk Carriers' Cargo Holds
Bulk carriers have a practical and comparatively simple layout. In most cases, the bridge, accommodation, superstructure, and engine room are located aft, leaving the forward and midship area clear for cargo holds and hatchways. This arrangement provides more direct access for shore loading and discharging equipment.

Most bulk carriers are fitted with Upper Wing Tanks (Topside Tanks). The underside of these tanks forms sloping surfaces in the upper part of the hold, assisting cargo flow and reducing trimming requirements. They also provide ballast capacity and help improve ship stability when the ship is in ballast or partly laden condition.

Self-Trimming Bulk Carriers are designed with sloping surfaces around the upper and lower parts of cargo holds so that free-flowing cargo naturally moves toward the centre and fills hold extremities more effectively. This reduces the need for manual trimming and can reduce shore labour. However, the expression should be used carefully because no bulk carrier is perfectly self-trimming for every cargo. Some Shipowners prefer the term Easy-Trimmer because it avoids the implication that no trimming will ever be required.

In some trades, Upper Wing Tanks (Topside Tanks) may be used for free-flowing cargoes such as grain. The tanks are drained, cleaned, dried, and loaded. At the discharging port, the cargo may be released into the cargo hold below through openings. This process is known as Bleeding Wing Tanks. It allows the ship to use space that would otherwise remain empty and can improve cargo intake for light cargoes.

The bottom of each cargo hold is the tanktop, which forms the top of the double-bottom tanks. Some bulk carriers are fitted with Lower Wing Tanks (Side Tanks). The sloping upper surfaces of these tanks create Hoppered Holds. Hoppered Holds help direct cargo toward the centre of the hold, reduce cargo residue, improve discharge, and reduce the risk of cargo shifting. Some con-bulker and multipurpose designs have flatter hold floors to suit containers, steel, or project cargo.

Bulk Cargo Stowage
Bulk cargoes differ significantly in density and stowage factor. Heavy cargoes such as iron ore occupy relatively little space per tonne, while lighter cargoes such as barley, grain, or woodchips occupy much more space. A ship carrying iron ore may reach its load line with holds only partly filled. A ship carrying barley may fill all holds before reaching maximum deadweight.

Heavy cargoes must be loaded with careful attention to stability and hull strength. If dense cargo is concentrated too low and too centrally, the ship may become too stiff, creating rapid rolling and heavy structural loads. Certain bulk carriers are hold-strengthened for heavy cargoes and may be permitted to load alternate holds, such as Holds 1, 3, and 5 in some designs. Alternate hold loading may speed cargo handling and support multi-port operations, but it must be approved by the ship’s loading manual and structural limits.

Stowage planning must consider bending moments, shear forces, tanktop loading limits, draft, trim, stability, cargo angle of repose, moisture content, shifting risk, and the requirements of the cargo declaration. Some cargoes can liquefy, some can self-heat, some emit gases, and some are sensitive to contamination or moisture. A bulk carrier’s design must therefore be matched to the cargo’s physical and chemical properties.

Bulk Carrier Ships' Cargo Gear
Some bulk carriers are fitted with shipboard cargo gear, while others rely entirely on shore equipment. Geared bulk carriers are valuable in trades involving smaller or less developed ports. Gearless bulk carriers are preferred in large-volume trades where specialised terminals handle cargo faster and more efficiently than shipboard gear.

Self-Discharging Bulk Carriers are equipped with systems that allow them to discharge cargo without ordinary shore grabs or cranes. Some use onboard conveyors, bucket elevators, screw systems, or boom discharge arrangements. These ships are often designed for regular industrial trades such as coal, aggregates, cement, or similar commodities. They can be extremely efficient where the shore receiver lacks full terminal infrastructure.

Cargo Grabs (Grab-Fitted Bulk Carriers) may be carried onboard and used with ship cranes or derricks. This can make the ship more independent and attractive for ports where grabs are unavailable. Some bulk carriers have a Gantry Crane, which travels longitudinally along rails and can serve different holds. Gantry arrangements are common in some specialised self-unloading or industrial trades.

For large bulk carriers, onboard cargo gear is usually a disadvantage because it adds weight, maintenance cost, obstruction, and capital expense. Capesize, Newcastlemax, VLOC, ULOC, and Valemax ships normally trade between terminals with powerful shore loading and discharging systems. Clear hatch access is more valuable than shipboard gear in such trades.

Bulk Carrier Ships' Cargo Fittings
Most bulk carriers are not fitted with sophisticated mechanical ventilation in every hold, but many are equipped with Fire-Smothering (CO2-Fitted Bulk Carriers) systems for cargo spaces. Fire-smothering systems are important for cargoes that may heat, ignite, or generate flammable atmospheres.

Most bulk carriers are fitted with Steel Hydraulic Hatch-Covers. Handysize and Supramax ships often have folding hatch covers opening fore and aft, while larger bulk carriers commonly have Side-Rolling Hatch-Covers. Side-Rolling Hatch-Covers move sideways and allow large hatch openings, improving grab access and cargo productivity. Hatch covers must remain weathertight because water ingress can cause serious cargo claims, especially for grain, fertilizers, steel, cement, sugar, salt, and other moisture-sensitive cargoes.

Specialized Bulk Carrier Ships

Woodchip Carriers: Woodchip Carriers are designed for high-stowing cargoes with low density. They may be 40,000 to 50,000 DWT or more, but their value lies in cubic capacity rather than heavy cargo strength. Woodchip Carriers usually have large boxy holds and very high volumetric capacity. They are unsuitable for dense cargoes such as iron ore because their tanktops and hold arrangements are not designed for such concentrated loads.

Timber Carrier (Lumber Carrier): Timber Carriers are designed to carry timber, lumber, and similar forest products in holds and on deck. They have arrangements for safe deck stowage, including stanchions, securing chains, lashings, and strong hatch covers. A properly secured timber deck cargo can allow use of a lumber load-line (timber load-line), increasing permissible cargo intake under applicable rules. Safe securing is essential because timber cargo shifting at sea can endanger the ship.

Logger (Log Carrier): Loggers are often between about 15,000 and 35,000 DWT and are commonly fitted with cranes capable of handling heavy logs. Logs may be carried in holds and on deck. Deck logs are secured with Stanchions (Stanchions-Fitted Bulk Carrier), chains, and securing equipment. There are Permanent Stanchions and Collapsible Stanchions. Collapsible Stanchions can be lowered to improve access during loading and discharge. Where steel stanchions are not fitted, Temporary Wooden Stanchions may sometimes be prepared from suitable cargo logs and placed into Stanchion Sockets.

Ore-Carriers: Ore-Carriers are built for dense mineral cargoes, especially iron ore. They have strong tanktops, reinforced cargo spaces, and hold arrangements designed for heavy cargo concentration. Many modern ore carriers exceed 200,000 DWT, with Valemax-type ships exceeding 400,000 DWT. Their trading range is limited by draft and terminal capability, but their unit cost can be very low on long-haul iron ore routes.

Bulk Cement Carriers: Bulk Cement Carriers are specialised ships fitted with mechanical and pneumatic systems for loading and discharging cement. Some operate almost like floating storage or bagging facilities. Ordinary bulk carriers may sometimes be adapted for cement or clinker cargoes by cutting Cement Holes in hatch covers, but such modifications must be approved by the Classification Society. Charter-party clauses should allocate the time and cost of cutting, approval, and rewelding, and should state whether the time counts as laytime.

2- General Cargo Ships

General Cargo Ships carry mixed cargoes and are now often called Multi-Purpose Ships (MPP). Their role has changed but not disappeared. They remain important where cargo is too varied, too heavy, too awkward, too small in quantity, or too port-specific for pure bulk carriers or container ships.

Historically, general cargo ships carried the world’s manufactured goods, packaged cargoes, bagged commodities, drums, machinery, vehicles, steel, timber, and project cargo. Liberty-type ships of around 10,000 DWT became famous after the Second World War. Later designs such as the SD14, Freedom type, and other replacement designs improved cargo access and operational flexibility. Modern Multi-Purpose Ships usually have aft accommodation, wide hatch openings, strong decks, cranes, and flexible hold layouts.

General Cargo Ships: Cargo Liners and Tramps
Multi-Purpose Ships operating in deepsea trades are often smaller than modern bulk carriers and container ships, commonly around 10,000 to 25,000 DWT. Some operate on liner-like services, especially in project or regional trades. Others trade as tramp ships, following available cargo opportunities. Traditional Cargo-Liners have declined because containerisation absorbed much general cargo business, but multipurpose tonnage remains important where container carriage is unsuitable.
General Cargo Ships and Liquid Cargoes
Older general cargo ships sometimes carried liquid parcels in deep tanks, but parcel tankers and tank containers now dominate most liquid trades. Modern Multi-Purpose Ships focus more on containers, steel, break-bulk cargo, project cargo, timber, bagged goods, and selected bulk commodities. Some designs still provide flexibility, but the specialist tanker market now handles most liquid cargoes more efficiently.
General Cargo Ships' Holds
Many modern General Cargo Ships are Tweendeckers. A Tweendecker has a main-deck (weather-deck) and a lower tweendeck, dividing the cargo space into upper and lower areas. The upper area is called the Tweendeck Space, while the lower area is the Hold-space. This arrangement is useful for bagged, baled, drummed, palletised, and mixed cargoes because it reduces crushing and allows cargo segregation.

General Cargo Ships often have more separate cargo spaces than pure bulk carriers. This helps when several cargo parcels are loaded for different receivers or discharge ports. Modern Multi-Purpose Ships may also carry containers and bulk cargo, making them versatile commercial tools. The bottom of the hold is the Tank-Top, which is the top of the Double-Bottom Tanks used for ballast, fuel, or other ship services.

General Cargo Ships' Cargo Fittings
General Cargo Ships need cargo fittings to secure and protect many different cargoes. Many are fitted with Fire-Smothering Equipment (CO2 Fitted-Ship) because cargoes such as fishmeal, jute, cotton, or other combustible goods may present fire risks. Some are fitted with Mechanical Ventilation or Electrical Ventilation to reduce moisture damage and sweating, especially for bagged rice and similar cargoes.

Modern Flush Tweendeckers have tweendeck hatch covers level with the surrounding deck, allowing forklifts to operate more efficiently. Older ships had Tweendeck Hatch Coamings, which improved safety but obstructed cargo handling. Columns, pillars, coamings, and other hold obstructions must always be checked before fixing a ship for bulky or project cargo.

Cargo-Battens were traditionally fitted along hold sides to keep cargo away from damp steel surfaces and improve air circulation. They are now less common because they are costly to maintain and interfere with bulk cargo operations. Modern cargo protection may use dunnage, kraft paper, cargo nets, plastic sheeting, timber, bamboo, mats, or other materials. Dunnage protects cargo from water, moisture, movement, and pressure damage.

Cargo securing may require Lashings, Lashing Pad-Eyes, wires, chains, shackles, twistlocks, turnbuckles, and other Lashing Materials. A modern ship must carry a Cargo Securing Manual describing available fittings and their safe loading limits. If extra fittings are welded for a particular cargo, the charter party should state who pays for installation, survey, removal, and repair.

General Cargo Ships and Bulk Cargoes
Some General Cargo Ships can carry bulk cargo, but the ship must be suitable for the cargo's density, shifting risk, and loading method. Certain ships are fitted with permanent Partial Center-Line Bulkheads to reduce cargo shift. Older ships sometimes used temporary Wooden Center-Line Bulkheads. Modern Multi-Purpose Ships are often designed to carry bulk cargo without special temporary fittings, but this should never be assumed without checking the ship's manuals and particulars.
General Cargo Ships and Containers
Containerisation changed general cargo ship design. Modern Multi-Purpose Ships often have squarer holds, stronger tanktops, container fittings, hatch cover loading capacity, and weather-deck arrangements for containers. Ship stability, visibility from the bridge, lashing strength, and deck loading limits must all be considered before loading containers on a non-cellular ship.
General Cargo Ships' Ballast and Bilges
Older general cargo ships sometimes had Deep-Tanks with heating coils for liquid cargoes. Some cargo holds could be flooded for ballast and were better described as Floodable-Holds. After hold washing, dirty water drains through bilges fitted with filters or strum boxes to prevent solid material from blocking pipes and pumps. Before loading bulk cargo, bilge openings must be protected so cargo does not enter the bilge system.

Shelter Decker (What is Shelter Decker?)

Shelter Decker is a term often encountered in the short-sea and coaster trades. Historically, shelter deck designs were used to maximise cargo capacity while reducing registered tonnage under old measurement rules. Lower registered tonnage could reduce port costs, crew requirements, and certain liabilities. The tonnage rules that encouraged these designs have changed, but the term survives in some markets. Today, where Shelter Decker is used, it is often understood as a type of tweendecker.
General Cargo Ships' Cargo Gear
Derricks are traditional cargo-handling equipment. They are relatively simple, robust, and inexpensive. A derrick consists of a vertical supporting pillar called a Samson Post, a boom, and rigging such as wire ropes, blocks, and tackles. Derricks are operated by winches and can be useful in ports with limited shore facilities.

All cargo lifting gear must be tested and certified for SWL (Safe Working Load). Classification societies or recognised authorities issue certificates. Charter parties should include a warranty that ship’s gear certificates are current and will remain valid. Failure to maintain certificates may cause stevedores to refuse work, create delay, or expose the Shipowner to serious liability if injury or damage occurs.

Derricks Union Purchase
Union Purchase is a derrick rigging method in which two derricks are arranged to move cargo between shore and ship quickly. It can be efficient for bagged or general cargo in labour-intensive ports. However, once rigged, the working range is restricted, and cargo must be brought to and taken away from specific positions. The method also reduces effective lifting capacity and is unsuitable for heavy lifts.
Swinging Derricks
Swinging Derricks use two parallel derricks and adjacent winches to create a faster and more flexible cargo-handling arrangement. The system can maintain speed while improving the ability to swing the load between hatch and quay. It may use a suspended weight or deadman to maintain tension. The system is more capable than ordinary union purchase but still requires experienced operation.
Self-Swinging Derrick or Crane-Derrick
Self-Swinging Derrick or Crane-Derrick operates more like a crane. It uses its own associated winches and does not interfere with neighbouring hatch operations. A trained operator can control it efficiently, often with joystick control. The Velle type is one well-known commercial example.
Stulcken Derricks
Stulcken Derricks are heavy-lift derrick systems fitted to some general cargo ships. While ordinary derricks may lift 5 to 15 tonnes and heavier conventional derricks may lift up to around 50 tonnes, Stulcken systems can lift much heavier cargoes, in some cases hundreds of tonnes. They are arranged to serve hatchways fore and aft of the Samson Post structure and are especially useful for heavy project cargo.
Double-Rigged
Double-Rigged means that two (2) derricks serve each hatchway. For chartering purposes, the number, position, reach, and lifting capacity of derricks or cranes must be checked carefully. Cargo gear can determine whether a ship is suitable for a particular project, port, or cargo.
Electrically Powered Cranes
Most modern Multi-Purpose Ships are fitted with Electrically Powered Cranes. Cranes are more precise and versatile than many derrick arrangements. They are self-contained and do not require Samson Posts. Typical ship cranes may range from about 5 to 40 tonnes SWL (Safe Working Load), while some modern ships carry higher-capacity cranes or can combine two cranes for heavier lifts. Cranes are more expensive to maintain than derricks, but they are often commercially superior in modern project and multipurpose trades.
Ships' Hatch Covers
Many ships use steel hatch covers commonly described as Macgregor Type Hatch Covers, reflecting the influence of MacGregor hatch cover designs. Folding hatch covers open with a concertina-like movement. Side-Rolling Hatch Covers roll sideways or to the hatch ends and are common on larger bulk carriers. Piggy-Back Hatch Covers stack one panel on another. Pontoon Hatch Covers are lifted on and off, commonly in container ships and some multipurpose designs.

Modern hatch covers are usually hydraulically or electrically operated. They must be maintained, tested, and kept weathertight. Moisture damage to cargo is often linked to hatch cover leakage, defective rubber packing, poor compression, damaged cleats, corroded channels, or bad maintenance. Charter parties frequently require Shipowners to keep hatch covers efficient and watertight.

Ships' Hatchways
The number of holds and hatchways is important in ship descriptions. A ship may have four holds but six hatches, or five holds and five hatches, depending on design. Some ships have twin hatches side by side to improve access to the sides of the hold. Twin hatches help with bulky cargo but require a centreline support structure that can create obstruction.

In Tweendeckers, tweendeck hatchways are usually aligned with weather-deck hatchways, but older ships may differ. Shipbrokers should check hatch dimensions, hold access, and obstructions before fixing cargo that requires special handling, forklift access, long pieces, or heavy lifts.

3- Containerships

Containerships are designed to carry containers on fixed routes and scheduled services. They are the modern successors of traditional cargo liners. Large containerships operate between advanced container terminals with gantry cranes, yard systems, and rapid turnaround procedures. Most large containerships are gearless because shore terminals handle cargo faster than shipboard cranes.

Containerships are usually chartered by liner operators such as MSC, Maersk, CMA CGM, Hapag-Lloyd, COSCO Container, and Ocean Network Express (ONE). The largest ships are commonly employed on long-term time charters or owned directly by liner companies, while smaller feeder and regional containerships are more active in the charter market.

Containers are carried below deck in Cell Guides, which are steel guide structures that keep containers aligned and secure. Containers may also be carried in tiers on deck. Capacity is measured in TEU (Twenty-Foot Equivalent Units). A 40-foot container is commonly described as an FEU, but for ship capacity it is counted as two TEU. Each container position is called a Container Slot.

Feeder Containerships distribute containers between major hub ports and smaller regional ports. They may carry a few hundred to a few thousand TEU depending on size and trade. Some feeder ships are geared, especially where smaller ports lack shore cranes.

Hatchless Containership: A hatchless design has cell guides extending above the weather deck, reducing hatch cover handling and speeding operations.

Shiptainer: A ship-borne container gantry crane may be called a Shiptainer.

Fully Cellular Containership: A containership fitted throughout with cell guides.

Fully Fitted Containership: A containership equipped with container securing equipment such as lashings, twistlocks, strengthened decks, and related fittings.

4- Ro-Ro Ships

Ro-Ro Ships (Roll On - Roll Off Ships) are designed for wheeled cargo. They range from simple ferries to sophisticated deepsea car carriers and passenger ferries. Their main advantage is that cargo can be driven on and off the ship through ramps, reducing reliance on shore cranes and allowing rapid port turnaround.

Deepsea Ro-Ro Ships may carry vehicles, trailers, tractors, rolling machinery, palletised cargo, project cargo, and sometimes containers or break-bulk cargo. Access is often through a stern ramp that can be slewed or adjusted to fit different berth arrangements. Internal ramps or lifts connect the cargo decks.

Ro-Ro ship capacity may be described in Lane Metres, especially for trailer carriers. Trailer-Carriers carry road trailers, trucks, and similar wheeled units. Railway-Ferries or Train-Ferries carry railway wagons and may have deck rail tracks connected to shore rail systems by precise ballast control.

Pure Car Carriers (PCC) are designed for motor cars. They have fixed decks, large ventilation systems, and rapid loading and discharge capability. Pure Car and Truck Carriers (PCTC) are more flexible, with adjustable deck heights for trucks, buses, construction machinery, and larger vehicles.

5- Specialised Ships

5.1- Livestock Carriers

Livestock Carriers are designed to transport live animals, usually sheep or cattle. Sheep carriers and cattle carriers differ mainly in deck height, ventilation, animal handling arrangements, and space requirements. These ships need fodder storage, fresh water supply, waste removal systems, ventilation, non-slip decks, ramps, drainage, veterinary arrangements, and strict welfare management. Many livestock carriers are converted ships, although purpose-built units also exist.

5.2- Refrigerated Ships (Reefers)

Refrigerated Ships (Reefers) carry temperature-sensitive cargoes such as fruit, vegetables, meat, fish, and other perishables. Traditional reefers were highly specialised and fast, with insulated holds and refrigeration machinery. Modern reefer ships may have pallet-friendly decks, side doors, forklifts, and arrangements for rapid handling. However, refrigerated containers have taken a large share of this market because container lines can provide door-to-door temperature-controlled transport.

5.3- Heavy Lift Ships

Heavy-Lift Ships carry cargo that is too heavy, too large, or too complex for ordinary cargo gear. Smaller heavy-lift ships may look like Multi-Purpose Ships but have very strong cranes, sometimes able to lift around 1,000 to 2,000 tonnes in combined operation. They carry transformers, turbines, industrial modules, yachts, cranes, locomotives, and project cargo.

Semi-Submersible Heavy-Lift Ships use ballast systems to submerge their cargo deck below water. Floating cargo such as drilling units, offshore structures, barges, or damaged ships can be positioned over the submerged deck. The ship then deballasts and rises, lifting the cargo clear of the water. Discharge is performed by reversing the process.

5.3- Barge Carrying Ships

Barge carrying ships transport floating barges as cargo units. Barges are larger than containers and can carry substantial cargo parcels, but many are Dumb units without propulsion. Systems such as Lighter Aboard Ship (LASH), SeeBee, and BACO (Barge Aboard Catamaran) use different methods to lift, float, or carry barges onboard a mother ship. Despite their theoretical efficiency in certain river-sea trades, barge carrying ships remain a specialised niche.

5.4- Combination Carriers

Combination Carriers are ships able to trade in both dry bulk and wet bulk markets. The main idea is to reduce ballast legs by allowing the ship to carry oil in one direction and dry bulk cargo in another. The most familiar type is the OBO (Ore/Bulk Oiler), which can carry ore, coal, grain, or crude oil in the same cargo spaces after suitable cleaning and preparation.

The commercial advantage of OBO (Ore/Bulk Oiler) ships is flexibility. However, maintenance, cleaning, safety, corrosion control, and market acceptance can be more demanding than with specialised ships. Many Charterers prefer dedicated tankers or bulk carriers, but combination carriers can still be profitable where trade patterns suit their flexibility.

The second type is the O/O (Ore/Oiler), designed mainly for ore and oil. An O/O (Ore/Oiler) has limited suitability for low-density dry bulk cargoes because its cargo spaces may fill before full deadweight is used. It is therefore mainly associated with iron ore and crude oil trades rather than general bulk employment.

6- Short-Sea Ships (Coaster Bulk Carrier Ships)

Short-Sea Ships (Coaster Bulk Carrier Ships) are not merely small versions of ocean-going bulk carriers. They are designed for regional trades, short voyages, restricted drafts, small ports, rivers, canals, bridges, tidal berths, and frequent port calls. Their commercial strength is flexibility.

Modern coasters often have one large box-shaped hold, a wide hatch opening, and steel hatch covers. This arrangement makes loading and discharge efficient and allows the ship to carry bulk cargo, project cargo, steel, pallets, or other short-sea cargoes. Some older coasters have concrete, timber, or tarmac protection over tanktops, while modern designs usually have steel tanktops suitable for varied cargoes.

Some coasters are fitted with movable bulkheads. These allow the ship to divide the hold into sections so that a main cargo parcel can be carried in one area while a smaller parcel is kept separate. Movable bulkheads also help prevent slack cargo movement when the hold is not completely full.

Low-profile coasters are designed to pass under bridges and trade through rivers and canals. They may have folding masts, collapsible wheelhouses, or low air draft arrangements. These design details allow them to serve inland terminals and industrial customers that cannot receive larger ships.

Summary

Bulk Carrier Ships and other dry cargo ships are designed around the cargoes, ports, routes, and commercial needs they serve. The dry cargo market includes pure bulk carriers, general cargo ships, containerships, Ro-Ro ships, specialised ships, and short-sea coasters. Each type exists because no single ship design can efficiently serve every cargo and every trade.

Bulk carriers are classified by deadweight size, from Coaster Bulk Carriers and Handysize Bulk Carriers to Capesize Bulk Carriers, VLOC, ULOC, and Chinamax or Valemax ships. Sub-classes such as Supramax, Ultramax, Kamsarmax, Newcastlemax, Setouchmax, Seawaymax, Malaccamax, and Dunkirkmax show how cargo demand and port restrictions shape ship design.

Bulk carrier design focuses on efficient cargo handling, strong tanktops, suitable hatch access, safe stability, effective ballast arrangements, and hold geometry that reduces trimming and cargo residue. Terms such as Upper Wing Tanks (Topside Tanks), Self-Trimming Bulk Carriers, Easy-Trimmer, Hoppered Holds, Gearless, Self-Discharging Bulk Carriers, and Side-Rolling Hatch-Covers are important in understanding how these ships operate.

General Cargo Ships and Multi-Purpose Ships (MPP) remain important because they can carry cargoes that do not fit easily into pure bulk or container systems. They may have tweendecks, cranes, derricks, cargo securing systems, ventilation, dunnage arrangements, and flexible hold layouts. Container ships, Ro-Ro ships, reefers, heavy-lift ships, livestock carriers, timber carriers, ore carriers, cement carriers, and combination carriers each serve more specialised cargo needs.

For Shipowners, Charterers, and Shipbrokers, the correct ship is not simply the largest ship available. The best ship is the one that matches the cargo, port, draft, loading method, discharge method, voyage distance, stowage factor, cargo sensitivity, and commercial objective. Understanding bulk carrier ship sizes and dry cargo ship types is therefore essential for safe operations, efficient chartering, and profitable shipping business.

Standard Dry Bulk Carrier Size Classifications:

Category Typical DWT Range Common Description
Handysize 10,000 – 39,999 DWT Flexible, trades in smaller ports
Handymax 40,000 – 49,999 DWT Larger Handysize, often interchangeable
Supramax 50,000 – 59,999 DWT Gear-equipped ships (cranes/grabs) for mid-range cargoes
Ultramax 60,000 – 69,999 DWT Modern evolution of Supramax, typically 61K–65K+ DWT but can reach up to 69K DWT
Panamax 70,000 – 84,999 DWT Fits old Panama Canal locks (pre-expansion)
Kamsarmax 82,000 – 85,000 DWT Max size for Kamsar, Guinea
Post-Panamax 85,000 – 99,999 DWT Too large for old locks, smaller than Capesize
Capesize 100,000 – 220,000+ DWT Too large for canals, used for iron ore and coal