Then there's the raft floor. It can be a single sheet, which provides virtually no insulation, or double and inflatable, which is a real plus in anything but tropical waters. Some rafts are even fitted with inflatable cushions or other insulation material; be careful, though, as these cushions and materials can be of questionable quality and/or inadequately secured to the floor. I generally prefer a well-secured, inflatable-floor insert, however, because the crew can remove it to gain access to the raft bottom in case it gets holed, or to use the cushion for other purposes.

A life raft's canopy opening should be large so that boarding it is as easy as possible.BOARDING THE RAFT

Even if you properly launch a raft and it inflates, you still need to get aboard. Large-diameter tubes provide more freeboard and security, but are hard to climb over. Unfit or injured people need assistance regardless. If everyone is alert, especially in calm conditions, your crew may board the raft as they would a dinghy, never hitting the water.

In tougher conditions, one fit, trained crew member can jump on the canopy, crawl inside, secure gear, and get ready to aid the next person. Additional jumpers might injure those already aboard, so when it's rocking and rolling, guests can hook their arms around the raft painter, enter the water without letting the painter go and pull themselves to the raft.

In my opinion, the best raft provides large-print instructions and pictograms, strong handholds all around the perimeter, a long-tongued, inflated platform on which to belly up and crawl aboard, extra handholds on the exterior within easy reach of the platform and a web hand ladder that stretches across the interior. If the hand ladder has quick-disconnect clips, anyone in the raft can quickly clear it out of the way or re-deploy it. I also like a platform "hinged" onto the raft so the crew can pull it up and secure it once all are aboard. Web boarding ladders are the most difficult to use, best suited as secondary entries fit on some canopies.

CAPSIZING CONSIDERATIONS

Intensive stability testing in tanks and at sea over the years indicates that nothing can guarantee a raft won't capsize. Everything from loading of occupants (stay on the high, upwind side) to raft shape and canopy design play a role in stability, but water ballast and a properly designed drogue are the primary tools to prevent capsizing.

In recent decades, designers have focused on increasing water ballast. Some boaters prefer the large, torroidal ballast systems on some Switlik rafts or a single immense bag pioneered by Givens. Increasing water ballast increases loads on the structure, however, requiring heavier construction. As a compromise, most rafts rely on ballast bags or pockets. Regulations stipulate that pockets be distributed around the perimeter.

Even with this, ballast weight and bag drag on the downwind side may detract from stability and prevent directional stability. The varying motions of a spinning raft can plague a crew, especially sealed under a canopy. Spinning also routinely exposes the boarding opening to breaking waves. Only some bags are fit with retraction lines, so if survivors need to reduce drag on the downwind side or increase maneuverability, they can pull some or all of the bags up. All pockets must be large, strongly built, and adequately weighted or "sprung" to open quickly. The actual effectiveness of each system depends primarily on total ballast weight and raft size, but it is tough to evaluate any raft's stability without experiencing it firsthand in the water.

Canister rafts are intended to be mounted on deck.For many, the drogue has proven the most effective stability aid, however, and it keeps a raft from spinning. I prefer the sea anchor rode to be attached to the raft opposite the primary entry opening, keeping the entry on the downwind side. Some anchors self-deploy as the raft inflates, which may add an entangling line to the water, but allows survivors to catch up to the raft if it gets separated from the boat. If it's not self-deploying, it should at least be clearly at hand yet secured so it doesn't escape if the raft capsizes. Since big waves can tumble and tangle most drogues, the best type is "Improved Icelandic," a long cone with webbing ringing its bridle to prevent a breaking crest from throwing the cone through the bridle.

Now, even with the right gear, capsizing can still happen. The good news is, I've yet to encounter a typical ballast-pocket raft that could not be re-righted by an adult in controlled conditions. In harsh conditions, it's more like riding a bronco standing up, pulling the re-righting reigns attached to the other side. Of course, it's critical that there are clear directions on the raft, secure places to wedge one's feet on the tube and strong re-righting line. Some rafts are also "self righting." The huge ballast on Givens-style rafts appears to re-right them. Others with large, high, canopy tubes create a shape that is unstable upside down, and roomy for survivors.

Just as you don't want your first experience in a boat to be during an emergency, get a feel for a liferaft in controlled conditions, like a boat show – or better yet, a survival training course. Climb into the display models; only by doing so can you appraise the space, ventilation, and light, how easy it might be to work, whether anyone can stretch out. Are instructions crucial in the early stages of survival obvious and waterproof, hopefully printed on the raft? How strong and secure are the interior handholds and attachment points? Are there auxiliary equipment bags, windows and rain catchments? How good are the canopy light and light-reflective strips outside? How quickly can you find essential gear like the dull-tipped knife at the entry, so you may quickly cut the raft free from the boat? Is the emergency-equipment bag flying about on an entangling tether, or is it kept secure, its contents organized and waterproofed? And how good is the actual equipment?

It's adventure on a small scale that, if needed for real, is likely to keep the adventure on a small scale.