The Captain Rob Cozen
Certified Marine Surveyor NewsLetter
April 1998 Archive

"Life Rafts"

The BOAT/U.S. Foundation For Boating Safety tested eight different life rafts in 1991, all of which performed as advertised. Excerpts of their findings, Foundation Findings Report #12, Survival Rafts, are reprinted here to help you choose which raft is right for you. (Complete reprints of the article are available by contacting the BOAT/U.S. Foundation.) You must assess your risks and your probability of rescue within a given time, based on the type of boating you do and the location-whether you're near shipping lanes or popular fishing spots near shore, or you're planning a cruise to some of the more isolated parts of the world. Consider the features outlined below in making your decision.

Basic Types of Rafts

There are three basic life raft designs: coastal, offshore, and ocean-going. Coastal rafts should only be considered if there is a high probability of rescue within a day, because they lack features needed for long-term survival, such as double inflation tubes. Offshore rafts extend survival time to four or five days by including supported canopies and two buoyancy tubes (the second tube acts as an emergency backup). Ocean-going rafts are designed for long-term survival of at least 30 days, and are required equipment on most commercial vessels and by some international racing authorities.

What to Look for in a Life Raft

Below is an outline of the basic features to consider, with notes from our tests.

SOLAS vs. USCG-Approved Life Rafts

SOLAS standards are very strict, as they are with all SOLAS-approved gear. SOLAS standards require that approved rafts have a boarding platform, additional safety gear and considerably more interior space than commercial-grade models.

Ballast. Most flat-bottomed survival rafts use a combination of water-filled ballast pockets and a cone-shaped sea anchor on a long (60' or more) line to prevent capsizing. The filled pockets resist the lifting action of wind and waves, and the anchor adds drag to keep the raft edge down. Toroidal-shaped and hemispheric ballast systems have proven most effective in preventing heavy-weather capsize. Bags with large holes for rapid filling also help keep the raft from blowing over before passengers can board.

Anchors. The sea anchor is an integral part of the stability design. It creates drag, prevents "riding", reduces capsizing, and turns the raft door away from oncoming waves.

Buoyancy Tubes. Life rafts come with either one or two automatically inflating buoyancy tubes. Short-term survival coastal rafts have one tube with two air chambers to prevent complete deflation in the event of a puncture. Double-tubed rafts found on all offshore and ocean-going rafts increase freeboard and reduce the likelihood of swamping. The second tube should support two-thirds of the raft's rated capacity when the largest buoyancy chamber is completely deflated.

Painter. When secured to your boat, the painter keeps the raft from floating away, and when pulled, it activates the inflation mechanism. More than one pull is usually needed to activate inflation, because there is between 15-55' of slack to take in. Many painters have a colored marker indicating that the next pull will activate the carbon dioxide (CO2) cartridge to inflate the raft.

Manual Inflation. Temperature changes cause raft air pressure to fluctuate. When hot, the tubes expand and excess air pressure is released through the over-inflation valves. When cool, the tubes contract and will require topping off. Three types of manual pumps are available: an oral inflation tube, which is next to impossible to use effectively; a foot pump that works best on a firm floor, even though there is none; and an accordion-like hand pump that is by far the easiest to use.

Canopies. Although canopies shield survivors from sun, wind, and water, they can leave crowded passengers feeling claustrophobic and sick because of the reduced view of the horizon and, in some cases, a notorious rubber interior smell. Canopies with large entryways, port holes, and separately furled panels offer greater horizon views and increase ventilation. Dark-lined interiors, like blue, are easier on the eyes; they diminish the sun's glare on a bright orange canopy. Canopies are supported by arches that keep the raft from inflating upside down and allow occupants greater interior room. Some arches are independent of the buoyancy tube and require manual inflation once occupants board. These rafts run a greater risk of inflating upside down but are easier to board from the mother ship.

Storage Containers. Rafts come in either a soft, flexible valise for below deck storage, or a durable fiberglass canister for mounting on deck. Carefully choose the most accessible and convenient location on your boat - account for raft weight and size. A life raft is useless if you can't get to it when you need it. Remember, anyone on board may have to carry it topside, and valuable minutes will be wasted if you have to search through a cluttered locker to find the raft.

Floors. Rafts have either single-layer or double floors. Double floors insulate passengers from energy-draining cold water, reduce the feeling of sitting on a half-filled water bed by keeping the floor from swallowing your feet and legs, and help to eliminate the bumps and bruises from curious marine life. Certain designs secure the additional floor with button-like fasteners that create depressions in the raft floor and allow water to collect. Some floors keep passengers drier using a highly porous material to trap splashed water.

Capacity Ratings. Capacity ratings specify the maximum number of people a raft will hold, based on a minimum of approximately four square feet per person. They do not consider comfort, space needed to perform raft maintenance and repair work, or room to store extra survival gear. If you plan to carry the maximum number on board, you had better hope for a quick rescue.

HOW TO REDUCE RAFT COSTS

Rafts should be serviced annually by certified technicians to ensure proper performance. Like your car, if you follow the recommended service schedule, you'll pay less than if you wait until something breaks. Fees range from $150-$200 for annual inspections; $300-$500 for the three-year inspection; and $400-$600 for five-year service inspections, depending on raft size and gear replaced.

Email us: rcozen@marine-surveyor.com

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Captain Rob Cozen
Master Marine Surveyor
P.O. Box 220
Somers Point, NJ 08244
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copyright 1997, Captain Rob Cozen, all rights reserved.