Bulk Carrier Ship Parts
Anchor: Bulk carriers have two bow anchors and one spare. Anchors raised and lowered by a special winch known as the windlass, or perhaps by a capstan on very large ships. The cable drops down off the windlass into the chain locker. A few ships have stern anchors. When considering an anchorage for a ship, the depth of water, the nature of the bottom, and prevailing winds should be known. On long salvage tows, the anchor cable is often used as part of the towing line.
Ballast: Ballast is weight loaded to make the ship seaworthy when she has to proceed to sea without cargo. Originally this could have been anything, often just sand and stones from the beach. However, modern ships use seawater in the double bottom tanks, peak tanks, and also specially constructed ballast tanks.
Bilge: Bilges are virtually ditched at each side of the hold where all the condensation, sweat, and leaking liquids can drain and be pumped out. Before any loading, particularly of foodstuffs, they must be cleaned out and inspected. On some ships, the double bottoms are carried out to the sides, so there will be no bilges. When this occurs a ‘well’ or drain is made in an isolated section in the double bottom which serves the same purpose.
Bulkhead: Bulkheads are vertical partitions or walls. All ships must have a specified number of bulkheads, depending on their length. By dividing the ship into watertight divisions they reduce the danger of sinking if one compartment is holed. They also reduce the risk of fire spreading. The forward bulkhead, called the ‘collision bulkhead’, is made particularly strong as it would have to withstand considerable buffeting if the ship steams to a repair yard having had her bows severely damaged in a collision. One of the problems of Ro/Ro ferries has been the large undivided car deck spaces which make them very vulnerable to flooding and to the subsequent loss of stability.
Decks: The number of decks depends entirely on the trade and cargo for which the ship is designed. On some liner trades, she may have three or four; passenger ships will have many more. Ships designed to carry cars may have several portable decks. On the other hand, tramp vessels carrying bulk cargoes may only have one deck.
Deep Tanks: These are holds with facilities such as wash plates, pipelines, and oil-tight hatches so that they can be used for the carriage of liquid cargoes or water ballast.
Derricks – Cranes
Derricks – Cranes: are used on general-cargo ships to lift the cargo on and off. They are usually capable of lifting between five and ten tons but the ship may be fitted with one or more heavy-lift derricks i.e. Jumbo Derricks to cope with the heavier items of cargo. Derricks are usually used in pairs. One is fixed over the hold and the other over the quay. The two runners are then joined together and the cargo lifted out of the hold by the ship derrick. It is moved over the ship’s rail by slacking on the ship derrick and heaving on the over-side derrick. The over-side derrick then lowers the cargo onto the quay. This is known as the ‘union purchase’ method. This has the advantage of rugged simplicity and universal acceptance by stevedores. The shipboard crane is initially more expensive but it requires fewer stevedores. Cranes can pick up and put down the cargo over a much wider area, cranes have better ‘spotting’ facilities, and it is quicker. The ship’s lifting gear is subject to Merchant Shipping Notice No M1347 concerning safety and it must be clearly marked with its SWL (Safe Working Load).
Double Bottom Tanks
Double Bottom Tanks: a double skin along the bottom of the ship, from a ship safety point of view, these were not necessary for tankers with their smaller divided cargo spaces; however, from an environmental-safety consideration, the American OPA 90 legislation has caused the new generation of tankers to have double skins. Double Bottom Tank’s purpose is to provide a safeguard in the event of a grounding. Double Bottom Tank space is used for water ballast, freshwater, or bunkers.