From Wikipedia, the free encyclopedia
Oil tankers generally have from 8 to 12 tanks.[1] Each tank is split into two or three independent compartments by fore-and-aft bulkheads.[1] The tanks are numbered with tank one being the forwardmost. Individual compartments are referred to by the tank number and the athwartships position, such as "one port", "three starboard", or "six center."[1]
A cofferdam is a small space left open between two bulkheads, to give protection from heat, fire, or collision.[1] Tankers generally have cofferdams forward and aft of the cargo tanks, and sometimes between individual tanks.[2] A pumproom houses all the pumps connected to a tanker's cargo lines.[1] Some larger tankers have two pumprooms.[1] A pumproom generally spans the total breadth of the ship.[1]
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Hull designs
A major component of tanker architecture is the design of the hull or outer structure. A tanker with a single outer shell between the product and the ocean is said to be single-hulled.[3] Most newer tankers are double-hulled, with an extra space between the hull and the storage tanks.[3] Hybrid designs such as double-bottom and double-sided combine aspects of single and double-hull designs.[3] All single-hulled tankers around the world will be phased out by 2026, in accordance with amendments to Annex I of the MARPOL Convention.[3] IMO distinguishes three categories of tankers that will be phased out:[4] • Category 1 - oil tankers of 20,000 tonnes deadweight and above carrying crude oil, fuel oil, heavy diesel oil or lubricating oil as cargo, and of 30,000 tonnes deadweight and above carrying other oils, which do not comply with the requirements for protectively located segregated ballast tanks (commonly known as Pre-MARPOL tankers) • Category 2 - as category 1, but complying with protectively located segregated ballast tank requirements (MARPOL tankers), and • Category 3 - oil tankers of 5,000 tonnes deadweight and