Re: [Paddlewise] skeg plans

"Peter A. Chopelas" wrote:
} Subject: [Paddlewise] skeg plans
> Ulli Hoeger asked about skeg materials and I thought I'd add my two cents 
> worth to give everyone something to think about:
> 
> I would not use aluminum in a skeg and would not have aluminum in the water 
> as either a skeg or a rudder on any kayak because there is some evidence it 
> attracts sharks.  It is a well know fact that AL in sea water under goes a 
> slow chemical reduction called electrolysis, it breaks down the molecules 
> on the surface and discharges a weak electric current in the water.  It has 
> been suspected by researchers that this current is mistaken by the sensing 
> organs on a shark as an injured fish thrashing in the water.  There also 
> have been a number of antidotal reports that support this idea because 
> sharks have attacked boat props, rudders, etc. including one scary story of 
> a sea kayaker I think in the Deep Trouble book who had an aluminum skeg on 
> his kayak.

This is very weak "evidence" - this sounds like an untested 
hypothesis.  

C'mon, this is as bad as the old "aluminum pots cause Alzheimers"
idea - it's ridiculous to worry about all the untested or poorly
tested ideas that come up.

(FYI, for those who don't remember :-), the aluminum & Alzheimers
connection was made by some researchers who thought they found
more aluminum in the brains of Alzheimers victims than in other 
people.  As it turned out, this study was not repeatable.  But
even if it had been, the idea that eating out of aluminum pots
causes aluminum to acculumate in the brain was *highly* 
speculative, and completely untested by this study.  Yet I know
of many people who threw away their aluminum pots in fear.)

For a contrary speculative hypothesis, how about the idea that many
predatory fish will strike at shiny objects?  That might well account
for the "antidotal" (anecdotal) strikes at props, rudders, etc.
Personally, I think this one is far better supported than the Al
electrolysis idea, but helps to show just how useless this speculation
is as a guide to action - until someone tests it, it's just 
nothing more than a speculative idea.

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