Lifeboat
From Wikipedia, the free encyclopedia
- For the 1944 movie, see Lifeboat (film).
A lifeboat is a rigid or inflatable boat designed to save the lives of people in trouble at sea. The term has somewhat different meanings in British and American usage. The British usage emphasizes specialized vessels kept in harbour or near a harbour, often manned by volunteers, designed to quickly reach a ship in trouble. The term "lifeboat" in American usage generally refers to rigid or inflatable vessels carried by larger ships to allow passengers and crew to escape in an emergency.
The first boat specialized as a lifeboat was tested on the River Tyne on January 29, 1790. William Wouldhave and Lionel Lukin both claimed to be the inventor of the first lifeboat. One example of an early lifeboat was the Landguard Fort Lifeboat of 1821, designed by Richard Hall Gower.
In U.S. waters, rescue-at-sea is part of the duties of the United States Coast Guard, which employs its multipurpose ships and aircraft in this role. The Coast Guard is also responsible for making sure that the proper type and number of lifeboats (American usage) are available and kept in good repair on any large ship. "Lifeboat drills" are a part of a cruise experience.
Inflatable lifeboats, also called life rafts, may be equipped with auto-inflation carbon dioxide canisters or mechanical pumps. A quick release and pressure release mechanism is fitted onboard ships so that the canister or pump automatically inflates the lifeboat, and the lifeboat breaks free of the sinking vessel. Commercial aircraft are required to carry auto-inflating life rafts in case of an emergency water landing. They are also kept on offshore platforms.
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[edit] Ship-launched lifeboats
These are large whaleboats designed to be lowered from davits on a ship's deck. They are designed to be unsinkable, with buoyancy that cannot be damaged. They have a cover that can be erected to form a storm shelter and sunshade. The cover can usually collect rainwater, and is visible from the air. They usually carry flares and mirrors for signaling, three days of food and water, oars, an engine, heater and basic navigational equipment.
The International Convention for the Safety of Life at Sea (SOLAS) and the International Life-Saving Appliance Code (LSA) require a specific list of emergency equipment to be carried on each lifeboat and liferaft used on international voyages. Modern lifeboats should also carry an Emergency Position-Indicating Radio Beacon (EPIRB) and either a radar reflector or search and rescue radar transponder.
Traditionally lifeboats for passages in the Pacific or Indian Oceans were thought unsafe unless they permitted self-rescue. Thus these traditionally included sailing equipment, navigational equipment, solar water stills, rainwater catchments and fishing equipment. Lifeboats for the North Sea include an electric heater for the engine oil, which is left on in cold weather.
A very commonly used lifeboat is a 25-man inflatable; in the United States Navy it is named the Mark 6. The lifeboat is compact and made of separate compartments, or tubes, as a redundancy against puncture. Carbon dioxide canisters and hand pump facilitate inflation of the vessel. A built-in canopy is often included as part of a lifeboat against harsh weather. Lifeboats furthermore carry essential survival gear, including food, water, de-salter kits, bags, sea dye, first aid kits, fishing kits, light/smoke distress signals (Mark 13), and heliograph mirrors.
Most yachts carry lifeboats. Some use dual-purpose dinghies, often with the express plan of self-rescue, while others use inflatable life-rafts. The equipment and arrangements are very similar to larger commercial lifeboats.
[edit] Origins of the lifeboats onboard ships
By the turn of the 20th Century larger ships meant more people could travel, but safety rules in regard with lifeboats stayed out of date. It was after the sinking of the RMS Titanic on April 15, 1912, that a movement began to require a sufficient number of lifeboats on passenger ships for all people on board.
The need for so many more lifeboats on the decks of passenger ships after 1912 led to the use of most of the deck space available even on the large ships, creating the problem of restricted passageways. This was resolved by the introduction of collapsible lifeboats, a number of which had been installed on the Titanic (see Birthon Boat Company).
The ship's tenders of modern cruise ships are often designed to double as lifeboats.
Also see the discussion in dinghy and liferaft.
[edit] Modern life boats
Modern motor life boats (MLB) originated as life boats that had been modified with the addition of an engine and provided more power to get in and out of the swell area inside the surf. They can be launched from shore in any weather and perform rescues further distances out. Older lifeboats relied on sails and oars, which are slower and dependent on wind conditions or manpower. Both types remain in use. All lifeboats of this type generally have modern electronic devices such as radios and radar to help locate the party in distress and carry medical and food supplies for the survivors.
The MLB was initially developed by the United States Life Saving Service in 1899, of which models derived from this hull design remained in use until 1987. The United States Life Saving Service later would become the United States Coast Guard and continue in its original mission of saving lives.
The Royal National Lifeboat Institution (or RNLI) maintains lifeboats around the coasts of the United Kingdom and Republic of Ireland, manned by unpaid volunteers with equipment funded through voluntary donation - web-site at www.rnli.org.uk. Most Scandinavian countries also have volunteer lifeboat societies. The local branch of a society generally schedules practices, maintains a lifeboat and shed, and is contacted by commercial marine radio operators when a rescue is needed.
In Australasia, surf lifesaving clubs operate inflatable rescue boats (IRB) for in-shore rescues of swimmers and surfers. These boats are best typified by the rubber Zodiac and are powered by an outboard motor. The rescue personnel wear wet suits.
The Rigid Hulled Inflatable Boat (RIB) is now seen as the best type of craft for in-shore rescues as they are less likely to be tipped over by the wind or breakers. Specially designed Jet rescue boats have also been used successfully. Unlike ordinary pleasure craft, these small to medium sized rescue craft often have very low freeboard so that victims can be taken aboard without lifting. This means that the boats are designed to operate with water inside the boat hull and rely on flotation tanks rather than hull displacement to stay afloat and upright.
The Dutch lifeboat association (KNRM) has put many efforts in developing jet-driven RIB lifeboats. This had resulted in 3 classes. The largest is the "Arie Visser-class: length 18,80 m, twin jet, 2 x 1000 hp, max. speed 35 kts, capacity 120 persons.
Lifeboats are also operated inland at specific events, organisations such as the Royal Life Saving Society (RLSS UK) provide coverage of rivers, lakes and such like.
[edit] Other usages
When the Apollo 13 command module was damaged by an explosion in the service module, the lunar module was used as a lifeboat as it had separate life support, propulsion and guidance systems that remained functional (though it was not a lifeboat in the sense that it was detached from the main vehicle).
The International Space Station is equipped with a "lifeboat" known as the Crew Return Vehicle (CRV). A number of designs have been proposed over the years, but funding issues have prevented a dedicated CRV from being built and deployed. Currently, a Soyuz TMA capsule is used as an interim CRV in case there is a need for an emergency landing of the crew. Because the Station's crew size is limited by the lifeboat size, the Station only has three astronauts onboard, instead of the intended eight.
Any small self-contained spacecraft designed to operate as a life-preserving vehicle or escape pod for the crew of a spacecraft in distress might also be termed a "lifeboat", and this usage frequently appears in science fiction.
[edit] See Also
[edit] External references
- Life Boat Services Around the World
- Titanic's Lifeboats
- Garde côtière canadienne Canadian Coast Guard
- USCG National Motor Life Boat School USCG Station Cape Disappointment, WA
- Royal National Lifeboat Institution United Kingdom
