Date: Wed, 04 Nov 1998 14:22:08 -0600
From: "Wolfgang Brinck" <wolfgang.brinck@hksystems.com>
To: baidarka@lists.intelenet.net
Subject: Re: baidarka FOLDABLES AND STIFFNESS
I would like to re-iterate that a baidarka built to a more or less traditional
design, even one that uses aluminum tubing is more flexible than a hard shell
boat. So my point was that even if you go for maximum stiffness in a skin on
frame boat, it will still be plenty flexible. Making it intentionally more
flexible by lashing it loosely or by leaving the skin slack will not create a
better boat. But it may well be that a naturally flexible baidarka would be
less fatigueing than a comparably sized fiberglass kayak.
Fatigue is a factor and puts an upper limit to how long a kayaker can stay on
the water, but making a baidarka more flexible than it should be will not
decrease paddler fatigue. If anything, making a baidarka more flexible will make
it slower, hence increasing fatigue by keeping the paddler on the water for a
longer time.
I have heard that wooden ships when freshly caulked tended to be stiff and would
perform better after they had loosened up a bit, but they were of a different
construction than baidarkas, so the parallel does not necessarily apply.
Wolfgang
Gene Smith wrote:
> With extreme trepidation, I'm going to sort-of disagree with Mr. Brinck. I
> do believe that he is correct when he says that fears of catastrophic
> failure due to over-stiffness are undoubtedly unfounded. However, I suspect
> that a somewhat more flexible boat will be more comfortable over a long
> period of time. How important is that? Well, I can't speak from experience
> in a seagoing kayak, but the vast bulk of what the word-twisters are pleased
> to call "negative outcomes" in the yachting world are caused by either
> alcohol or fatigue. Fatique works pretty much like alcohol in that it just
> unwires your judgement. I read of some hikers who were walking along the
> edge of a canyon that had a river flowing hundreds of feet below. The
> leader of the group discovered just how fatigued they all were when one of
> the hikers was found sitting on the canyon rim - trying to dangle his feet
> in the water! Things that matter little in an afternoon's paddle could get
> critical when your journey is measured in days. Therefore, I suspect the
> significance of "flexibility" might lie more in the realm of fatigue
> reduction rather than durability.
>
> There, I've stuck my neck out to the more experienced kayakers in the group,
> which would be pretty much everyone else besides me. What say those of you
> who have made long journeys? Am I paddling a load of manure here? Or is
> there some sense to my guess about "flexibility"? I know that there are
> sailboats that will hammer your fillings out in an afternoon's sail and
> others that you could sail a lifetime without much discomfort. How about
> kayaks?
>
> Gene Smith
> dry for a change in Houston
>
> >Historically, I think that early European mariners observed that baidarkas
> >were quite flexible compared to their own wooden boats. There also seemed
> >to be some trepidation that these quite flexible boats would come apart,
> >which they didn't. But this is no reason to try to make baidarkas flexible.
> >They simply are flexible by virtue of their light construction.
> >
> >I don't think that there is any danger of making a baidarka too stiff even
> >if you are using aluminum tubing. The materials and the method of
> >construction will assure adequate flexibility. Even if you epoxy the
> >lashings, there will still be some room for motion of the stringers
> relative
> >to the ribs.
> >
> >Even with light weight wood construction, I have never had any catastrophic
> >failures of the frame even when doing enders in surf and having the tail of
> >the baidarka pounded into the sand. All the damage I have ever done to the
> >frame has been on the beach when the baidarka encountered solid immovable
> >objects. Even then, the damage was localized to a rib or stringer and did
> >not render the boat as a whole unusable.
> >
> >Wolfgang
> >
> >