At the real risk of beating this issue to death, let me address three issues raised by other posts. I recognize that we are unlikely to experience the failure of a latex seal or, even more unlikely, that we would ever tear dry suit material. But, in a situation where we are knocked down or out of our boats (e.g., hitting a partially submerged rock or piling which is covered with barnacles, not a totally outlandish scenario) drysuit failure could happen. Risk management deals with the likelihood of an event occurring, but also looks at the severity or significance of the negative impact which would result if the event did, in fact, occur. A study conducted by the Navy and Coast Guard showed that a four inch cut in the shoulder of a drysuit caused the suit to completely fill with water immediately; the swimmer, wearing a PFD and using only the minimal activity needed to stay afloat, moved sufficiently to flush the water within his suit through the hole, virtually negating any thermal retention of warmed water --- the wetsuit principle of keeping a layer of warmed water next to the skin. The drysuit had no measurable survival value once compromised. If anyone's interested, I can provide the references on the study. Second, as to the relative value of Polartec Thermal Stretch material vs. regular fleece, it's in the design. Thermal Stretch (and Ruberized Thermal Stretch) emulate the principle of a wetsuit when they're wet --- holding a thin layer of body-warmed water against the skin; the membrane which comprises the middle layer of the composite material keeps water from flushing through, and the fleece inner layer compresses but retains the warmed water, also inhibiting the flushing action which would otherwise constantly vent off the body-warmed water. Bottom line: it works. I've tested my Thermal Stretch in cold water, swimming it in 38 degree water for 25 minutes; I got out because that's the time I arbitrarily assigned to be a worst case swim. I was very cold, and I'd probably lowered my body temperature by one or two degrees, but I was not borderline hypothermic and was essentially functional. Regular fleece or stretch fleece (like Polartec 200S) would have provided essentiall! ! y no thermal protection in the same water test. It doesn't work like a wet suit, and, when it's submerged, water can and will constantly wick off your body heat. (Given, the stuff is terrific, and, under a shell, will provide noticable thermal protection on land even when it's wet; but it's different when it's submerged.) It's the combination of the compression of the lycra (or elastic outer layer in the rubberized material), the inner membrane (which is breathable in Thermal Stretch and somewhat less breathable in Rubberized Thermal Stretch when dry), and the Polartec fleece inner layer which creates the wetsuit effect that provides swimmable survival protection. Where to get it? The problem is that many manufacturers put their own names on the product. Colorado Kayaks used to use both Thermal Stretch materials; they now seem to sell only the rubberized material, but check their site for more information: www.coloradokayaksusa.com. The folks at Mountain Surf sell a Thermal Stretch suit; see their catalog or site at www.mountainsurf.com. This stuff isn't cheap --- probably close to $200 for a jumpsuit. Is it necessary? It's a redundant safety factor which is of value to a few of us. Admittedly, the chance of my Kokatat GoreTex suit failing is slim, and it's very well maintained. But I do a fair amount of solo paddling, even in winter, and, while I don't do any long trips or major crossings, it wouldn't take much cold water to disable me if I crashed even a half mile off shore. So I use what I talk about. It's a personal call --- it's your call. Jack Martin Chair, Department of Redundancy Department *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced outside PaddleWise without author's permission Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.paddlewise.net/ ***************************************************************************Received on Tue Nov 02 1999 - 05:00:20 PST
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