Re: [Paddlewise] Efficacy of Sponsons on Canoes and Kayaks

Wow!

How times have changed. I remember when I first presented Risk Homeostatsis
to Paddlewise and the Wavelength and was nearly laughed off the net. Dr
Wilde and I got a bit of a chuckle out of it. He said that the response
should not surprise me as he had received vitriolic response to the theory
from people within the safety industry.

Ms O'hara's report disappointed me. When interveiwed I suggested that she
also interview experts on seaworthiness (naval architects and, in
particular, Dr C. J. Marchaj) and review the latest literature to learn  the
technical reasons why paddlers should excersize caution before subscribing
to the safety claims for sponsons. She did not and her report lacks any
technical support. I also suggested she visit the Givens Life raft web site
to see the perils of high initial stability and light displaceemnt but I see
she did not include that in her report possibly because her lack of
technical expertise would not reveal the connection.

In my interview with her I recall clearly pointing out the adverse
relationship between dynamic stability and displacent as wll as the dnagers
of considering only static stability as a criteria.and yet she made nothing
of that in her report. She attributes the stability of canoes to length/beam
ratio alone completely missing the point. She does acknowledege that her
study was not scientifically rigourous and as such I have to wonder "why
bother?"

In her defense she acknowledged that her report had more of a "preliminary"
focus and that she had not been asked to do an exhaustive technical study.

In a way I think she waffled in her conclusion and did not feel her report
addressed the issue as well as it could have. I suppose this could have
resulted from the study's focus. The Coastt Guard has a history of problems
when dealing with recreational boating (for example, the ludicrous loading
formulas and regualtions).

We can consider one a thing a certainty. Our friend who promotes the
sponsons will harvest all the positive comments and print them
out-of-context in his web site.

Cheers

John Winters
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