Re: [Paddlewise] Graphite for Bottoms

Bill wrote;
(SNIP)

>So why do I bring this up?  A year or so ago I was having a conversation
>with Robert Morris of Brewery Creek Small Boats, who teaches the
>construction of skin covered baidarkas, Greenland kayaks, etc.  Robert
>claimed that traditional baidarkas paddled faster than many people would
>think.  We discussed the fact that the original seal skins might have had
>an effect like adding some oil (or whatever) to the boundary layer and
>working like a visco-elastic fluid.  Does anyone have any definite
>knowledge of this?  Have there been any efforts to use visco-elastic
fluids
>to increase the performance of human powered vessels?  Does anyone know if
>there are coatings that might "ablate" and effect the drag performance of
a
>kayak or canoe?

Many years ago I coated the bottoms of my sailboats with Lux liquid
detergent believing it would reduce friction (as did others). We also tried
a lot of other goops that supposedly imitated fish slime. I doubt if any
worked but the psychological benefit may have been high.

Some tests on long chain polymers did show some friction reduction
(Catchpole,Canham,and Lon-Trans.RINA 1971) but problems existed. The
polymers had to be replenished constantly and the resulting pollution would
not be desirable in these enlightened times. Also the weight of the
polymers you had to carry offset the benefits of the reduced friction.

Paint manufacturers have been claiming all kinds of stuff over the year to
gull the rich sail boat  owner. Unfortunately, independent tank tests have
never been able to confirm their claims. That does not mean that some
ingenious inventor won't solve the problem some time in the future but so
far only the advertising writers have it licked.

Cheers,
John Winters
Redwing Designs
Specialists in Human Powered Watercraft
http://home.ican.net/~735769/



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