<< Is Kevlar "stronger" than fiberglass or is it just lighter? >> Kevlar fiber and cloth has superior tensile and tear strength to glass fiber and cloth. I think the real question is: " Are Kevlar composite boats "stronger" than fiberglass composite boats?" I believe the (long) answer is that, for the same weight boat, the Kevlar composite boat (usually a combination of kevlar and glass-fiber materials in polyester or vinylester resins) will be stronger and far less likely to suffer catastrophic failures (like the whole bow breaking off, versus just cracking) than the same model made solely with fiberglass. However, most manufacturers utilize the superior tensile strength of the Kevlar to make boats which are lighter but of approximately the same strength as their glass models, thus making them far more desirable to the customer who tends to worry a lot about weight. If I were ordering my "perfect" boat, I would request a heavier "expedition" Kevlar lay-up. What I would be looking for is a boat which is just as stiff, and considerably stronger than the (all) glass version, while saving (at most) 3 to 5 pounds (rather than the 10 to 20-pound savings of most Kevlar lay-ups). Steph Dutton had a special Kevlar boat made for his winter-time paddle of the Oregon coast, which weighed something like 15-20 pounds heavier than the stock glass model. It took tremendous abuse on that trip, then was later loaned to some no-mere-mortal who ran the Grand Canyon (yes, Class 5 sections and all) with its 16-1/2 foot hull loaded with full expedition camp gear. The boat looked beat, but unbroken. I wouldn't doubt you could drive a 16-wheeler over the thing. The reason people worry about spider cracking of the gel coat on Kevlar boats is because the lighter Kevlar boat is usually more flexible (while not necessarily weaker) than the standard-weight glass version. This is not a big problem for people who exercise a lot of care with their boats, but may give some grief to the more hell-bent adventurous, those prone to sit heavily on their decks, and to outfitters who must allow their boats to be used by the careless or uninitiated. Curved sections are stronger and more rigid than flat sections, so boats which have vaulted decks have fewer problems with gel coat cracking than those with flat decks, unless the manufacturer takes measures to stiffen the flat sections (coremat, carbon fiber, or others as mentioned by John Winters). Harold So. Cal. *************************************************************************** PaddleWise Paddling Mailing List Submissions: paddlewise_at_lists.intelenet.net Subscriptions: paddlewise-request_at_lists.intelenet.net Website: http://www.gasp-seakayak.net/paddlewise/ ***************************************************************************Received on Sun Mar 14 1999 - 20:42:47 PST
This archive was generated by hypermail 2.4.0 : Thu Aug 21 2025 - 16:30:05 PDT