These three words were drummed into my head in university. In studying structural engineering, we learned that these were the three criteria that had to be met in any design. Strength - it shouldn't break Stability - it shouldn't fall over Serviceability - it should meet its design objectives and satisfy the needs of the users. Strength is easy; we can develop analysis models and determine design parameters that, with safety factors, give us the strength we need. Stability is a bit trickier. Buckling and such is difficult to calculate and sometimes hard to prevent. But it's doable. Serviceability is a nasty. There are, for all intents and purposes, _no_ deterministic parameters that define serviceable. It is entirely a subjective thing. And in structural engineering and architecture, it is the thing of lawsuits! Recent discussions about the stiffness of kayaks have brought this back to my mind. John W. has commented (paraphrasing) "We know how to make it strong, but don't know how strong to make it." So by trial and error, we find kayaks are reasonably strong, though some, who push limits, prefer stronger. Stability is similar - we can stiffen the kayaks to the point that they won't fail by the deck or hull buckling. But serviceability? How do we define that? I've said that I want a kayak that is stiff enough to avoid oil canning and other hydrodynamics-spoiling effects but any stiffer is too heavy and expensive. Doug on the other hand, wants stiff, _stiff_, STIFF! Skin boat enthusiasts like their boats pliable and sensually moving _with_ the water. I think that to some extent, the stiffness issue is more a serviceability one than anything else. There is a degree of stiffness that is required, but beyond that it's subjective. Folks know what they want, but do they know what they need? I don't. I haven't seen hard data to allow me to judge the lower limits. I know my kayak performs well enough. I also know I keep thinking of building a skin-on-frame kayak. That will be much more fragile than my current kayak. I won't take it out in conditions that I'd take my Solstice. And I won't take my Solstice out in conditions that Doug'd take his armour-plated Nordkapp. So it goes. But each will be serviceable for _me_, since it suits my perceived needs. When you view your current or prospective kayak, don't get hung up on the limits of what is subjective. Mike *************************************************************************** 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/ ***************************************************************************
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