Wooden Boat People
By McKenzieDriftBoat.com
UHMW Chine Caps?
I'm replacing my chine caps. They we're pretty beat up after only one season. I used a soft wood instead of a hard wood (or maybe I need to work on my oarsmanship.)
I'm considering using a piece of UHMW for the chine cap. 1/2" x 2". I can get a continuous piece for each side at a reasonable price. I think I can fasten it and keep water from getting into the screw holes.
Anybody have any experience using UHMW for chine cap? Anything else I should be concerned about?
RB
Views: 1182
Replies to This Discussion
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Permalink Reply by Rick Newman on
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What are the temperature extremes in Wisconsin? The concern in climates with a wide range of temperatures is the expansion and contraction of UHMW. When used as a boat bottom in such climates the experiences shared by many on these pages is that the screws holding the material experience movement and hence looseness. This looseness can and has led to water and moisture being introduced into the wood.
A popular replacement for UHMW is stainless steel. Here is an online source that seems to have some good prices. http://www.onlinemetals.com/merchant.cfm?pid=637&step=4&sho... They list an eight foot length, .5 inch wide by .125" thick for just over $10.00. You could cut this into segments, drill and countersink the screw heads and not have to concern yourself with movement. I think that I will order some from this source for my boat. Thanks for the impetus to look this up!
Rick Newman
PS. Ray Heater and Cyrus Happy use stainless on the boats they build at Ray's River Dories.
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Permalink Reply by Guy Fredrickson on
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Rick,
Thanks for the "onlinemetals" link. I like the idea of a stainless steel strip on my white oak chine caps. I'll give that some more thought.
Guy
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Permalink Reply by Ron Bakken on
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Thanks Rick! I was so enamored with UHMW for it's durability but mostly cause it's so slippery.
I wish there was a way to make it work.
RB
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Permalink Reply by Sandy Pittendrigh on
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This one doesn't have a chine cap at all. ;=)
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Sandy, is this the new "flagship" that you will be building now you have retired? Better sharpen your adze!
Rick Newman
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Permalink Reply by Don Hanson on
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The Don Hill boat I restored recently came to me with UHMW chine caps and a stem cap of the same stuff. It was broken up and very brittle. Wouldn't be my choice. It left a bunch of the screws just hanging out and induced rot into the chine.
I think bronze 'rub rail' would make a great chine cap. I've seen it in various marine supply outfits...Jamestown distributors, for one (I think)... It is a bit pricey, but it would be 'appropriate' on a nice wooden boat.
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Don, good thought. Onlinemetals has bronze in rods and tubes. However they also have brass in .125" x ,75" and ,125" x 1" eight foot lengths are appx $22 and 28 respectively. Wouldn't brass work in a non-saltwater application? Would there be any problems besides a need for occasional maintenance to keep it shiny? I could see where a saltwater application could have issues with de-zincification.
Rick Newman
PS I may be traveling down the Gorge soon to pickup a trailer in Vancouver. I would love to meet you and see your operation. Would you consider a visitor?
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Brass is not such a great metal for use in water. I am no chemist, but I think there's something about it that makes it very prone to electrolisis.
Bronze is the 'traditional' boatbuilding metal. I think it develops a very thin coating of oxidation and that stops further degrading of the metal..
If I did a boat for myself, I think I would spend the cash and use some quarter round bronze 'rub-rail' for the chine caps protection, fastened on with silicone bronze wood screws, countersunk into the bronze and bedded in Dolphinite bedding compound.
Chine cap: They are on the sides, not the bottom, but yes, metal doesn't slip off rocks like UHM plastic.
You could also try to find some Ironbark wood. Ipe is another species of wood that I've recently had experience with when doing a wealthy friend's house. It is being imported as outdoor deck wood and seems like it would be excellent for the chine cap on a driftboat..Available online.
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Thanks Don! So far more cons than pros for using UHMW for chine cap.
The bottom of my boat and a small portion of the sides are black from epoxy with graphite. The sides and chine cap are painted so I don't have the nice wooden exterior to show off.
Using bronze or stainless covered chine cap, will there be a sort of drag when the metal goes over rocks?
RB
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If you were to install the brass or bronze which are "noble" metals and zinc or one of the less "noble" metals in a strong electolyte like salt water you can develop galvanic action between the two. Hence the installation of sacrificial zinc anodes on salt water boats and on the inside of metal lock gates like the ones Mike from Dirty Jobs had to replace on a show.
Since freshwater is such a weak electrolyte the possibility of galvanic action is less. If there is only one metal exposed to the water if you use silicon bronze screws like Don suggests you should reduce the possibility even further.
Kind of like a car battery when it is used up. The lead has been transferred from its solid form and suspended in the strong electrolyte (battery acid) until the acid has become too diluted. A related chemical reaction, while not exactly the same it is similar.
Too many years of electronics work and physics classes!
Rick Newman
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Permalink Reply by Kevin C. on
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1/4"x 3/4" steel strips screwed into white oak or mahogany with silicone bronze screws that do not penetrate the ply.After installation coat with penetrol.Gives bomber protection and will take a big hit ,cheap and durable.Keep enough water under the boat and there is no drag...
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Very interesting Kevin!
I had never heard of penetrol before. Did a little search and it looks like amazing stuff with many applications. http://rolledon.forummotion.com/t720-all-about-penetrol
Thanks.
RB
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