Re: [Paddlewise] Boat Construction

Mike, et al:
(Lots of snips)

Mike said:
>IMNSHO, CD uses too light a layup in the deck on all their kayaks.  I own a
>Solstice GTH and enjoy it.  The fore deck, being arched near the cockpit and
>peaked forward seems ok.  The rear deck, being flatish, seems just too soft.
>I trust it, but...
>
>It's interesting that CD's standard "expedition  grade" options (last I
looked)
>include heavier hulls and outside seams, but no beefed-up decks.

I think that is the biggest beef people have with the CD kayaks, and an
area often overlooked. I've seen the shallow arched decks fail to. Nothing
is immune if you underbuild - but then people want lightweight. When I'm in
the CD retail connected store, watching customers get qualified for a
possible sale, the number one question is "how light is it?"
 
>> Advertising in North America often
>> suggests to customers that modern light weight kayaks are quality products
>> with the implication that strength for rough water is concomitant with
>> that. Conversely, I also disagree with advertising aimed at getting people
>> into the sport, suggesting light is best and that heavier duty is only
>> needed for the few [...] 
>>
>
>That point is well taken, but it's true in other sports.  It also works
the other
>way.  A certain Canadian Coop based in Vancouver insists on selling xc
>ski equipment in Ontario that is well suited to BC's interior but not to the
>much-more-common resorts of the East.  Hence I've seen folks in skis that
>are too wide to fit into the ski tracks.  Caveat emptor.  It's up to us to
>spread the word by mouth that the ads should be taken with a grain of salt.

I have sort of a similar problem with mountain bikes. Some of th bikes from
California a great out in the Moab Desert - wide trails, technical at
times, but not too severe. Here in the heavy, steep rainforest trails of
the Pacific Northwest, replete with logs and roots galore, some of these
American frames break with regularity. Our Canadian bikes are heavy and
ugly, but man, do they shine in the rough.  
>>
>> >> 9. All the above guides/instructors I know, also usually order the extra
>> >> outside seams, [...]
>> >But reinforcing may result in local stress concentration that increases
the
>> >likelyhood of failure.  The key is a balanced design;[...]
>>
>> Yes, agreed for the most part. This is part of the reason the Brits stay
>> with straightforward lay-ups.
>
>You know, the more I think about it, the simplest seam is probably the best.
>Cosmetically, it would be a harder sell.  You've convinced me.  We can
>probably do without the H sections and just toss the idea of trying to get a
>strong seam with the geometric gyrations of wrapping around the H.
>It's a subtle difference from an engineering point of view, but heck - simple
>works.

People like the H section seems. They are sexy, and technical looking. I've
seen guys salivate over them in the retail CD store. Add a magenta gelcoat
color with the slick black extrusions, and you have a sale!!!

>
>> Stiff is good. Stiff is fun. Stiff is wonderful. Stiff lasts, stiff
survives. If its not stiffy, its
>> iffy! [...]
>
>You realize you're being emotional about this, don't you?

I think I called it subjective.

>Think about this - an infinitely stiff kayak, being slammed by a wave will
transmit _all_
>the force to the paddler.  Sorta like a car without crumple/impact zones.
>
>A kayak only needs to be stiff enough to avoid oil-canning and similar,
hydrodynamic
>messing-up effects.  Any stiffer is just cost and weight.
>

I'm not going to argue with an engineer, especially one who has actually
done stress tests. And I did cotton on to your earlier post about
compression and tension. Do try to remember Mike, I'm the guy who surfs and
storm paddles with rocks in his head, er, I mean kayak. Also, most of the
Brit boat dealers talk up the stiff hyperbole too. Lets just say that I'd
rather have stiffer than more flexible. Where the best compromise between
the two extremes is, I don't know. I do know that my boat is very stiff
now, and it feels wonderful. 


>> . And...my next boat will be wood-strip, built by
>> myself, to my specifications and covered in epoxy so that the whole kayak
>> is a homogeneous unit. Unless you can point me toward a one piece
>> fiberglass kayak, that's the direction I'm taking.
>
>The rambling at the end of my last post led me to think that this is a
really good solution.
>The wood strip lets you fool with curves that a S&G won't allow.  Wood is
an excellent
>core material (rot aside).  It's relatively affordable and doesn't need
exotic tools or autoclaves.
>You can glass it any way you like and the results may end up georgeous.
>
>I've got some crazy ideas for one-piece, fiber-reinforced kayaks, but that
can wait.

I'm just a working stiff (can't get away from that word!). If I did have
unlimited funds, I'd order a 70 lb Nordkapp in Kevlar and Carbon Fiber. I'd
have them leave off about an inch along the seam line, of both the deck and
hull, so that an 2 inch outside seam could be run along without being
applied to the gelcoat. It would be an expensive boat. 

BC'in Ya
Doug Lloyd
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