Selecting a Life Raft

Digg!

What they do
A life raft is designed to keep the crew of a boat alive until they can be rescued. Life rafts provide minimal environmental protection and create a larger visual and radar target for rescuers.

How they work
Life rafts are inflated by compressed gas, usually nitrogen and CO2, stored in a high-pressure cylinder. When the inflation lanyard is pulled, a valve releases the gas into the inflatable chambers, which takes about 20 seconds. The resulting inflated shape may be square, pentagonal, hexagonal, octagonal, elongated octagonal, etc.

Most have a protective canopy, supported by one or more inflatable tubes. Doors or openings allow occupants to board using an attached ladder, and to alter the amount of ventilation and storm protection according to the conditions.

The floor of the raft may be a single layer of fabric, a double layer inflated with air to provide insulation, a three-tiered laminate or a separate inflatable floor tied in place. Insulated floors greatly reduce heat loss and hypothermia, making the “raft experience” a little less grim.

Who needs a life raft?
There is little need for a life raft where rescue would be quickly forthcoming due to boating traffic and/or rescue agencies in your boating vicinity. Warm water extends survival time and reduces the need to get out of the water quickly to protect against hypothermia.

Inland, warm waters: You probably don’t need a raft, but you might consider having an inflatable or rigid dinghy available for rapid deployment.

Inland, cold waters: Strongly consider carrying a coastal life raft or large inflatable dinghy to keep you and your crew out of the water when operating in cold water. Hypothermia can kill anyone immersed in 50° water in just two hours, and quickly render you unable to function.

Coastal cruising/racing: One of the myths about boating is that coastal waters are somehow less threatening and require less rigorous safety gear than the open ocean. While it is true that your proximity to the coast may allow you to get to shelter before a storm or to get assistance more quickly than if you were further offshore, coastal sea conditions are frequently worse than those offshore, especially near points of land. Chances are you’ll spend less time in a raft when close to shore because you’ll wash ashore or be found sooner. Rafts used for coastal boating need to be seaworthy, but can include less gear for long-term survival than offshore rafts. Therefore, we recommend either premium coastal rafts or offshore rafts.

Offshore cruising/racing: Far from land, rescue agencies and safe harbors, you must have a raft in which you can survive for a week or more. Rafts for offshore use should be more commodious, and should have greater stability to survive storms at sea. SOLAS rafts, Offshore Plus and ISAF–Approved Bluewater rafts are recommended.

Raft types

Inflatable Dinghy: While not legitimate life rafts, inflatable dinghies can be pressed into service in an emergency. For coastal boating to nearby islands, or trips along the coast, a readily available dinghy is preferable to treading water while hypothermia saps your strength. The dinghy must be kept inflated and in a location where it can be launched quickly. The addition of a 3’ sea anchor for stability, a waterproof VHF radio and five gallons of water will greatly improve your crew’s survival chances.

Note:in all respects (except affordability) a dinghy is worse than our least expensive life raft, and should be considered only in coastal areas, and under the best possible conditions (which, incidentally, are not very common when you need a raft.) <a href="http://www.westmarine.com

Coastal ISO 9650 Life Raft: Coastal rafts are rated for open water, mostly protected or within 20 miles of a shoreline. Most rafts have a single buoyancy tube and either a manually–or automatically–erected canopy. Ballast systems vary, ranging from a single ballast bag about the size of a loaf of bread to the four large bags the better Coastal models have. The West Marine by Zodiac coastal raft is built with two identical stacked flotation chambers, an insulated foam floor and a self-inflating single–arch canopy. It meets the pre-2003 ORC offshore specs (see below). It is ideal for offshore fisherman and coastal cruisers who need a light, compact raft, but its equipment must be augmented with a Grab Bag.

Life Rafts: Formerly called the ORC life raft. ISAF life raft specifications were upgraded following the 1998 Sydney to Hobart race, where three sailors were killed because their life raft failed. These new requirements took effect in 2003. Rafts made to these specs are the most appropriate for boats encountering real offshore conditions for relatively short duration, but not taking a trans-oceanic voyage. The same, more stringent specs are recognized by governments around the world as ISO 9650. Two independent, stacked tubes provide redundant flotation should one chamber become damaged. The stacked tube design also provides more freeboard. Many have two entrances, and all have self-erecting canopies. Most will have deep triangular or rectangular ballast bags and a large drogue for stability.

SOLAS Trans–oceanic Life Rafts:Intended for the toughest conditions, with water temperatures below 41°F (5°C), these rafts include the most extensive list of equipment, and are the most heavily built, to allow self-sufficient survival for extended periods of time. Carried onboard boats in round–the–world races like the Volvo Ocean Race.

What to look for
Insulated floors are desirable in all rafts, even in warm water, due to the discomfort that comes from sitting on sub-body temperature surfaces. Although many record–breaking life raft survival episodes have occurred in single floor rafts, all survivors wished they had an insulated raft floor. If you use your boat in waters less than 65–70°, we strongly recommend this option.

Valise or canister storage: If you are going to store your raft on deck, you must use a canister version. We recommend that you also use a hydrostatic release, which will release your raft from its cradle and allow it to float to the surface if you can’t get to it before the boat sinks. If you store the raft below decks, make sure you can launch it in 15 seconds or less, and get a valise raft. It will be lighter, somewhat cheaper, but much less waterproof than the canister model. For offshore racers, rafts stowed below cannot be heavier than 40kg or 88lb.

Canopy Design: We strongly believe that self-inflating and self-erecting canopies are a necessity, not an option. This requires that some of the inflation gas be directed through a one–way valve to the arch tube(s). This is more expensive and more complicated than some of the other (bogus!) ways of doing it like using two paddles end to end as a tent pole, or using the heads of the occupants as the support.

Ballast Bags:Ballast bags keep the raft from blowing over before you board it, and keep the raft from being capsized by unruly waves. More ballast (more water volume) is generally better, especially when it is located along the perimeter of the buoyancy tubes. Interestingly, the drogue included with most rafts is critical in keeping the windward edge of the raft down on the water so that wind cannot get under the raft and blow it over. All drogues should be attached with large line, and should have a swivel (like those on the West Marine rafts.)

Ease of Boarding: Rafts are devilishly hard to board from the water, especially when cold and wearing soaked clothing. Most rafts have either one or two webbing ladders, which are a pain to climb. Other products may have a stirrup, while the best will have a boarding ramp. Ask yourself whether you could pull yourself up out of the cold water and into the relative security of the raft using the boarding methods provided. ISO rafts feature boarding ladders rated so a person wearing an inflated life jacket and heavy clothing can climb inside.

Emergency Equipment: Rafts do not come with lots of survival gear for economic and volumetric reasons. It is up to you to supply EPIRBs, water makers, extra flares, prescription medicine, radar reflectors, handheld VHF radios, etc. Raft manufacturers work at keeping the purchase price of rafts low, but they also realize that you will want to augment basic inventories with your own gear. An Abandon Ship Bag is vital to your survival. Standard raft equipment inventories generally include only those products that pertain to repairing the raft, while ISAF specification rafts may contain those items required for sailboat ocean racing like flares, paddles, bailers, and a flashlight. Regardless of the make or model, you will need to augment the standard inventory with your own gear.

Recommended minimum inventory items for Abandon Ship Bags:

  • 406 MHz EPIRB with or without GPS positioning
  • Katadyn Survivor 06 watermaker. Several solar stills would be a distant second choice.
  • Ship’s inventory of flares and other emergency signaling devices
  • Waterproof VHF radio with long shelf life batteries and replacement batteries
  • Ship’s medical kit including prescription medicine and reading glasses

Repacking your Raft
Generally, life rafts must be repacked each year to keep your warranty in effect. This is done for three reasons:

  • To replace dated items like flares, food, and water
  • To inspect for water damage and to make sure the cylinder is full
  • To fold the raft differently so it doesn’t wear through in folded areas

Life raft repackers should be licensed or approved by the raft manufacturer. Just because a guy hangs out a shingle that says Life Raft Repacking, don’t assume he is qualified for your Switlik, Avon, West Marine, Zodiac or whatever raft you have. Authorized repackers have the correct parts and have an inventory card with your own gear.

Some rafts, especially canister rafts packed in a vacuum inner-pack, can extend their first repack date for several years. Inside every West Marine raft, for example, is a piece of water-sensitive paper that shows through the inner vinyl bag. If this paper shows that no moisture is present, the repacker can seal the raft back up for the first and second scheduled repacks. This can save $300 in the first three years of ownership.

Digg!

Advertisements

One response to “Selecting a Life Raft

  1. Hi, these rafts sound awesome.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s