> "Peter A. Chopelas says: > > 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. > I hadn't heard the shark story before; fascinating. But not all alminums are subject to corrosion in salt water. Alloys containing manganese, magnesium, or chromium, or magnesium and silicon, like 6061, are particularly resistent- it's the copper containing alloys like 2024 that corrode easily. Alclad plates, which have a coating of pure aluminum, are very resistent to corrosion. Alclad 6061 would be a good choice for skegs. *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced/forwarded outside PaddleWise without author's permission Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
> I hadn't heard the shark story before; fascinating. But not all alminums > are subject to corrosion in salt water. Indeed, there are many aluminum hulled sailboats cruising the oceans of the world. Last I knew, it was considered an excellent material for a hull, and you see them with no paint or exterior coating. A bit expensive, and one does of course always have to be aware of galvanic corrosion (which arises mostly from the *contact* of certain dissimilar metals with each other in a salt water environment). I also have a small daysailor that has an aluminum rudder, which has performed well since the boat was born in 1978. So far, no shark attacks (knock on fiberglass). Mark *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced/forwarded outside PaddleWise without author's permission Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
"Sailboat Restorations, Inc." wrote: > > > I hadn't heard the shark story before; fascinating. But not all aluminums > > are subject to corrosion in salt water. > > Indeed, there are many aluminum hulled sailboats cruising the oceans of the > world. Last I knew, it was considered an excellent material for a hull, and > you see them with no paint or exterior coating. A bit expensive, and one > does of course always have to be aware of galvanic corrosion (which arises > mostly from the *contact* of certain dissimilar metals with each other in a > salt water environment). I also have a small daysailor that has an aluminum > rudder, which has performed well since the boat was born in 1978. So far, > no shark attacks (knock on fiberglass). And, lots of gill net boats around here are all-aluminum. No shark attacks, AFAIK, over the some 25 years I have lived here. BTW, MJE, they are definitely not 6061 alloy. Something in the 5000 series, IIRC. Not necessarily related is the fact that salmon trollers intentionally put a little voltage onto their trolling wires -- they claim it improves their catch. And, no, I can't verify that, either. It could just be folklore ... like the "sturgeon's whistle" my fishing buddy blows when the bite is slow. He claims it works better than peanut shells but I hold out for loading up both of my hands with food -- that brings on a sturgeon bite for sure! -- Dave Kruger Astoria, OR *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced/forwarded outside PaddleWise without author's permission Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Michael Edelman wrote: > I hadn't heard the shark story before; fascinating. But not all alminums > are subject to corrosion in salt water. Alloys containing manganese, > magnesium, or chromium, or magnesium and silicon, like 6061, are > particularly resistent- it's the copper containing alloys like 2024 that > corrode easily. Alclad plates, which have a coating of pure aluminum, > are very resistent to corrosion. Alclad 6061 would be a good choice for > skegs. > For the record, Feathercraft uses anodized 6061-T6 aluminum tubing for its kayak frames and they have held up quite well against corrosion even on frames that are now approaching 20 years of use (the company started producing around 1981). ralph diaz -- ----------------------------------------------------------------------- Ralph Diaz . . . Folding Kayaker newsletter PO Box 0754, New York, NY 10024 Tel: 212-724-5069; E-mail: rdiaz_at_ix.netcom.com "Where's your sea kayak?"----"It's in the bag." ----------------------------------------------------------------------- *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced/forwarded outside PaddleWise without author's permission Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
Gabriel L Romeu wrote: > > Ralph, is the 6061 anodized or powder coated? > > regards, gabriel To my knowledge it is fully anodized. Feathercraft is very picky about where it sources materials. In the case of their aluminum, for example, they source from the US rather than any Canadian source despite the foreign exchange penalty and the clear brownie points they would get from soucing locally. They found the US source superior in the anodizing. Same with the hypalon skins (which were used on the boats until just last year before switching to new skins and new technologies). They went all the way to France to source it, again because they deemed the French hypalon best (I know it is what Nautiraid uses too and, from my empirical knowledge of foldables, seems superior in wear characteristics). People ask why Feathercrafts cost so much. The materials are part of the reason why a Khatsalano or K-1 runs in the $4K range. The real bargain, in my estimation, was the K-Light and now its successor the Kahuna, a 35 pound boat about 15 feet in length with fine on-the-water characteristics as well as ease of portability and within a range of acceptable assembly times (20 minutes or so). It costs $2,280 complete with seasock and sprayskirt. Not bad for a boat that is likely to give you 25 years of service, if you live that long! :-) best, ralph diaz -- ----------------------------------------------------------------------- Ralph Diaz . . . Folding Kayaker newsletter PO Box 0754, New York, NY 10024 Tel: 212-724-5069; E-mail: rdiaz_at_ix.netcom.com "Where's your sea kayak?"----"It's in the bag." ----------------------------------------------------------------------- *************************************************************************** PaddleWise Paddling Mailing List - All postings copyright the author and not to be reproduced/forwarded outside PaddleWise without author's permission Submissions: PaddleWise_at_PaddleWise.net Subscriptions: PaddleWise-request_at_PaddleWise.net Website: http://www.paddlewise.net/ ***************************************************************************
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