A double-hulled tanker refers to an oil tanker which has a double hull. They reduce the likelihood of leaks occurring compared to single-hulled tankers, and their ability to prevent or reduce oil spills led to double hulls being standardized for oil tankers and other types of ships including by the International Convention for the Prevention of Pollution from Ships or MARPOL Convention. After the Exxon Valdez oil spill disaster in Alaska in 1989, the US government required all new oil tankers built for use between US ports to be equipped with a full double hull.
The Exxon Valdez oil spill occurred in the Prince William Sound, Alaska, on March 24, 1989. Exxon Valdez, an oil supertanker owned by Exxon Shipping Company bound for Long Beach, California struck Prince William Sound's Bligh Reef, 6 mi (9.7 km) west of Tatitlek, Alaska at 12:04 a.m. and spilled 10.8 million US gallons (260,000 bbl) of crude oil over the next few days.
The International Maritime Organization is a specialised agency of the United Nations responsible for regulating shipping. The IMO was established following agreement at a UN conference held in Geneva in 1948 and the IMO came into existence ten years later, meeting for the first time in 17 March 1958. Headquartered in London, United Kingdom, IMO currently has 175 Member States and three Associate Members.
A ship is a large vessel that travels the world's oceans and other navigable waterways, carrying cargo or passengers, or in support of specialized missions, such as defense, research and fishing. Ships are generally distinguished from boats, based on size, shape, load capacity and purpose. Ships have supported exploration, trade, warfare, migration, colonization, and science. Ship transport is responsible for the largest portion of world commerce.
Naval architecture, or naval engineering, is an engineering discipline incorporating elements of mechanical, electrical, electronic, software and safety engineering as applied to the engineering design process, shipbuilding, maintenance, and operation of marine vessels and structures. Naval architecture involves basic and applied research, design, development, design evaluation (classification) and calculations during all stages of the life of a marine vehicle. Preliminary design of the vessel, its detailed design, construction, trials, operation and maintenance, launching and dry-docking are the main activities involved. Ship design calculations are also required for ships being modified. Naval architecture also involves formulation of safety regulations and damage-control rules and the approval and certification of ship designs to meet statutory and non-statutory requirements.
Ballast is used in ships to provide moment to resist the lateral forces on the hull. Insufficiently ballasted boats tend to tip or heel excessively in high winds. Too much heel may result in the vessel capsizing. If a sailing vessel needs to voyage without cargo, then ballast of little or no value will be loaded to keep the vessel upright. Some or all of this ballast will then be discarded when cargo is loaded.
Floodability is the susceptibility of a ship's construction to flooding. It also refers to the ability to intentionally flood certain areas of the hull for damage control purposes, or to increase stability, which is particularly important in combat vessels, which often face the possibility of serious hull breach due to enemy action, and which rely on well-trained damage controlmen to equalize and then stop flooding of the hull.
Marine engineering is the engineering of boats, ships, submarines, and any other marine vessel. Here it is also taken to include the engineering of other ocean systems and structures – referred to in certain academic and professional circles as “ocean engineering.”
A ballast tank is a compartment within a boat, ship or other floating structure that holds water, which is used as ballast to provide hydrostatic stability for a vessel, to reduce or control buoyancy, as in a submarine, to correct trim or list, to provide a more even load distribution along the hull to reduce structural hogging or sagging stresses, or to increase draft, as in a semi-submersible vessel or platform, or a SWATH, to improve seakeeping. Using water in a tank provides easier weight adjustment than the stone or iron ballast used in older vessels, and makes it easy for the crew to reduce a vessel's draft when it enters shallower water, by temporarily pumping out ballast. Airships use ballast tanks mainly to control buoyancy and correct trim.
A submarine hull has two major components, the light hull and the pressure hull. The light hull of a submarine is the outer non-watertight hull which provides a hydrodynamically efficient shape. The pressure hull is the inner hull of a submarine that maintains structural integrity with the difference between outside and inside pressure at depth.
A mid-deck oil tanker is a tanker design which includes an additional deck intended to limit spills if the tanker is damaged. The extra deck is placed at about the middle of the draft of the ship. This design is an alternative to the double-hull tanker design, and is superior in terms of spill volume.
The stability conditions of watercraft are the various standard loading configurations to which a ship, boat, or offshore platform may be subjected. They are recognized by classification societies such as Det Norske Veritas, Lloyd's Register and American Bureau of Shipping (ABS). Classification societies follow rules and guidelines laid down by International Convention for the Safety of Life at Sea (SOLAS) conventions, the International Maritime Organization and laws of the country under which the vessel is flagged, such as the Code of Federal Regulations.
The anti-torpedo bulge is a form of defence against naval torpedoes occasionally employed in warship construction in the period between the First and Second World Wars. It involved fitting partially water-filled compartmentalized sponsons on either side of a ship's hull, intended to detonate torpedoes, absorb their explosions, and contain flooding to damaged areas within the bulges.
Ship grounding or ship stranding is the impact of a ship on seabed or waterway side. It may be intentional, as in beaching to land crew or cargo, and careening, for maintenance or repair, or unintentional, as in a marine accident. In accidental cases, it is commonly referred to as "running aground".
An oil tanker, also known as a petroleum tanker, is a ship designed for the bulk transport of oil or its products. There are two basic types of oil tankers: crude tankers and product tankers. Crude tankers move large quantities of unrefined crude oil from its point of extraction to refineries. Product tankers, generally much smaller, are designed to move refined products from refineries to points near consuming markets.
The Coulombi egg tanker is a design that is aimed at reducing oil spills. It was approved by the International Maritime Organization (IMO) as an alternative to the double hull concept. The United States Coast Guard does not allow this design to enter US waters, effectively preventing it from being built.
Oil tankers generally have from 8 to 12 tanks. Each tank is split into two or three independent compartments by fore-and-aft bulkheads. 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."
Corrosion in Ballast Tanks is the deterioration process where the surface of a ballast tank progresses from microblistering, to hydroscaletric electration, and finally to cracking of the tank steel itself.
SS Kanguroo was a French heavy-lift ship built to transport submarines before World War I. She delivered submarines to Brazil and Peru before the war began. Requisitioned in 1914 by the French Navy, she was torpedoed by a German submarine in late 1916 and sunk at Funchal, Madeira.
A compartment is a portion of the space within a ship defined vertically between decks and horizontally between bulkheads. It is analogous to a room within a building, and may provide watertight subdivision of the ship's hull important in retaining buoyancy if the hull is damaged. Subdivision of a ship's hull into watertight compartments is called compartmentation.
