PFD's including 'wet' or 'dry'-suits are made that are intended for long term immersion in cold water. A flotation device known as the Steinke hood is used as an escape device to ascend from a stranded submarine.
The Mark 10 Submarine Escape and Immersion Equipment (SEIE) suit is intended to allow submariners to escape from much deeper depths than currently possible with the Steinke Hood. Some United States Navy submarines already have the system, with an ambitious installation and training schedule in place for the remainder of the fleet.
Because it is a full body suit, the Mark 10 provides thermal protection once the wearer reaches the surface, and the British Royal Navy has successfully tested it at six hundred foot depths.
Divers use buoyancy compensators to adjust their buoyancy while underwater and to provide positive buoyancy in an emergency to bring them to the surface or keep them at the surface. See main article : Buoyancy compensator.
Specialised lifejackets can also be seen used in a myriad of environments. Shorter-profile vests are commonly used for kayak racing, and high-buoyant types for river outfitters and other whitewater professionals. PFDs which include harnesses for tethered rescue work ('live-bait rescue') and pockets or daisy-chains for the attachment of rescue gear are made for swiftwater rescue technicians.
Ancient instances of the lifejacket can be traced back to simple blocks of wood or cork used by Norwegian seamen. The modern lifejacket is generally credited to one Captain Ward, a Royal National Lifeboat Institution inspector in the United Kingdom, who, in 1854, created a cork vest to be worn by lifeboat crews for both weather protection and buoyancy.
The Mae West was a common nickname of a Type B-4 life preserver (inflatable lifejacket), used during World War II by the Allies. The B-4 was invented by James F. Boyle. The preserver was khaki color, made of cotton with inflatable rubber bladders, with dimensions of 27.5" H x 12.75" W x 1.25" D. The nickname was based on the famously buxom figure of Mae West, one of the most popular actresses of that period.
Andrew Toti related that his mother was the inspiration for the invention of the Mae West life vest. He had bought a boat, and his mother was worried because he couldn't swim. He designed a personal life preserver filled with duck feathers. However, that was too bulky and heavy, so he used air. Toti sold the rights to the Mae West life vest to the US War Department in 1936 for US$1,600.
Throwable PFDs are deployed from a vessel or land into nearby water, to give the recipient buoyancy. They are often provided on ships, docks and other water-edges in case a person falls in the water. Throwable PFDs are usually ring-shaped (toroidal). Such a shape is easy to throw to a distressed person, can be grasped by a hand or hooked arm even in turbulent conditions, and is much easier to put on in the water than a lifevest.
U.S. Coast Guard
The U.S. Coast Guard rates PFDs in five types.
Type I - offshore
- The model best-suited to open and rough waters, a type I PFD provides more buoyancy than any other type. The design of a type I PFD allows it to turn most unconscious wearers into a face-up position with their head out of the water. This type requires a minimum adult buoyancy of 22 pounds, and because of its bulk it is generally not comfortable to wear when not on the water. These PFDs are only used in an emergency. They are typically jacket-shaped but sleeveless, and usually have multiple ties and belts for closure.
Type II - near
shore buoyancy vest
- Familiar to anyone who has rented a canoe or other pleasure craft, these are the bright orange vests also seen on water taxis and the like. They are a reduced version of the type I PFD, and provide a minimum 15.5 pound buoyancy. They will usually turn the face of an unconscious person out of the water, but are not as dependable as type I PFDs for this task. Type II PFDs are used near shore where a quick rescue is likely. They usually have one belt and one tie.
Type III - flotation
- Most popular with canoeists and kayakers, a type III PFD is best for conscious wearers who can keep their own faces out of the water. The minimum buoyancy is 15.5 pounds, but some designs have higher buoyancy (frequently 17 pounds). Type III PFDs are usually jacket-style and may have pockets, lashing hooks, tow belts, and other functions that enhance their application. They typically fit the wearer closely, and many zip or have buckles to close.
Type IV - throwable
- Throwable PFDs are designed for areas where there is constant boat traffic and rescue is immediate. They are commonly ring-shaped, but horseshoe and cushion type IV PFDs are also made. These are only a backup measure and should generally be thrown by someone with experience, as it is difficult to aim well, especially in rougher water. A cushion-style PFD has a buoyancy of 18 pounds, while a ring-style has a buoyancy of 16.5 pounds.
Type V - special
- These PFDs are intended for specific uses, such as whitewater activities or boardsailing. Their turning performance (keeping an unconscious person face-up) is rated according to PFD types I, II, and III; some may also require that they are worn in order to be effective. Type V PFDs come in a variety of styles, from full-body suits to work vests. Some have a safety harness and some provide protection against hypothermia (survival suits).
According to the Coast Guard, all recreational boats must carry one wearable PFD (Types I, II, III, and V) per person on board. Boats over sixteen feet in length are also required to carry a throwable (Type IV) PFD, but canoes and kayaks over 16' are exempt from this rule. Under some circumstances, a throwbag -- a throwable bag containing floating rope, used to extend a line to a nearby swimmer or boat -- can substitute for a throwable PFD.
PFDs must be approved by the Coast Guard (all PFDs will carry a label indicating they are USCG-approved; this label should never be removed) and they must also be in good condition, as well as being an appropriate size for the wearer. (Child-size PFDs have different buoyancy requirements than adult PFDs.) It is extremely important that wearable PFDs, if not actually on their designated person, be at least readily accessible. If an emergency arises, they must be situated in such a way that they can be easily put on.
Inflatable PFDs are sometimes considered more comfortable to wear, but they require proper care. They must have a full cylinder and indicators must read green. There are no Type IV inflatable PFDs, and they are sized only for adults. Type I and II inflatables have a buoyancy of 34 pounds, and type IIIs have a buoyancy of 22.5 pounds. There are also type V inflatable models, but their buoyancy ranges from 22.5 to 34 pounds.
Laws about PFD use vary from state to state. The only federal laws related to PFD use indicate that they are not required on racing kayaks, racing canoes, rowing sculls, or racing shells. Many states do require PFDs for towed activities such as water skiing, as well as when operating personal watercraft, during whitewater activities, and when sailboarding (even though sai lboards are not technically "boats" according to federal law).
Lifejackets are required to be stamped or labeled that they have been approved by the Canadian Coast Guard or Transport Canada in accordance with the Small Vessel Regulations. If a standard lifejacket does not fall under the standards described in the Life Saving Equipment Regulations, it must meet the applicable standards of the Canadian General Standards Board, the Underwriters Laboratories of Canada, the Canadian Standards Association, or the Society of Automotive Engineers. PFDs intended for children are specifically required to meet the standards established in the Personal Flotation Devices for Children standard from the CGSB. Standards for ring-type lifebuoys are established in the SVR, Schedule III, sections 4 through 14.
Pleasure craft not longer than six meters must carry an appropriately-sized PFD for each person on board, and a "buoyant heaving line" (throwbag) of at least 15 meters. If each person is wearing an appropriately-sized PFD, then additional devices are not required on personal watercraft or paddleboats. Sailboarders must wear a PFD unless they are involved in an official competition that includes a safety boat carrying PFDs for emergency use. In addition to lifejackets for each person, pleasure craft between six and eight meters must carry a 15-meter buoyant line attached to a throwbag or ring-type lifebuoy; those up to 12 meters must carry both a throwbag and lifebuoy. On boats up to 20 meters, the lifebuoy must be equipped with a light and buoyant line; boats over 20 meters require an additional lifebuoy.
The Small Vessel Regulations require inherently buoyant lifejackets to be worn in personal watercraft, for whitewater paddling, and by individuals under the age of 16 or smaller than 36.3 kg (80 lb). Inflatable PFDs are permitted to be worn on open boats and when the individual is on the deck of a boat that is not open. Sailboarders may not use automatically inflatable PFDs. Exceptions to the lifejacket requirements state that infants under 9 kg (20 lb) and persons with a chest size greater than 140 cm (55 in) are not required to have lifejackets carried on board pleasure craft. Additionally, a non-resident of Canada may bring their own PFD that conforms to the applicable laws of their country. Exceptions are also made for rowing shells, racing canoes, and racing kayaks while they are in formal training or official competition, but only if an accompanying safety craft carried a PFD for each member of the crew.
|The above article is licensed under the GNU Free Documentation License. From Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/life_jacket). 1/6/06|
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