COPPER ON BOTTOM

How did you attached the copper to bottom.

I am to start a Passagemake taker apart.

I like the idea of copper on bow, skids and skeg.

Like old ironsides bottom.

 


6 replies:

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RE: COPPER ON BOTTOM

Anthony,

Copper is expensive, heavy, soft, and corrodes to green in salt water. Typically, you have to tack or nail it to the wood because adhesive don't stick to it well. They used it on Old Ironsides because its poisonous and kept shipworms from destroying the hull. They also had a large crew for maintenance.

Dynel fabric saturated with epoxy is highly abrasion resistant (better than fiberglass) for.the bottom and skids. It's inexpensive and light. The key requirement is preventing water from getting to the plywood. IMHO, boats are not pieces of furniture, they do end up showing wear if you use them.

When we built my Peeler Skiff, we did insert a length of 1/2-inch stainless half-round under the fiberglass at the stem for collision, not abrasion, resistance. We launch the Peeler, About Time, off a shells, rocks, and gravel New England beach. She's much heavier than a NE Dory and the Brightsides on the bottom has held up well.

Cheers,

Dick

RE: COPPER ON BOTTOM

Dick's suggestion to use Dynel for abrasion-resistance I think has merit. Quite possibly Kevlar too but neither tend to 'wet out' in resin so if a bright exterior is your goal they're not good choices.

A reply I posted in another thread here caused me to wonder if perhaps powdered copper used as a filler (like microballoons, wood flour, silica, graphite, powdered aluminum...) might be worthwhile? Certainly would solve the issues over water being trapped underneath sheet copper, or issues over bonding to it.

 

RE: COPPER ON BOTTOM

Rats... meant to key in "wet out almost to invisibility". Forgive the omission.

RE: COPPER ON BOTTOM

SPClark,

I agree about Dynel fabric not being suitable for a bright finish, but copper isn't "bright" in a different way --- no way to see the wood underneath.

Interlux Perfection Two Part Polyurethane is extremely hard and glossy. Interlux Brightsides One Part Polyurethane has been very durable on the bottom of my boat. Dynel is quite abrasion resistent and better than glass cloth in that regard.. I don't know how abrasion resistent Kevlar is, but I do know that it's no fun to cut or work with.

I still cannot imagine using copper sheet on a small boat. There are, however, very hard, copper-based anti-fouling bottom paints that do not need to stay immersed. I also think that's extra expense and work for no gain.

Cheers,

Dick

RE: COPPER ON BOTTOM

Copper's probably best avoided (at least on underwater surfaces):

http://www.ruggedcoatings.com/single-post/2016/03/17/Copper-Bottom-Paint-Regulation

https://en.m.wikipedia.org/wiki/Anti-fouling_paint

http://ucanr.edu/blogs/blogcore/postdetail.cfm?postnum=4758

RE: COPPER ON BOTTOM

áááYou may also want to consider the added weight of the copper on a small boat. Remember copper is not light, if you are planning on manhandled it. Of course the take-a-part will help in that aspect. I used dynel as rub straps on a painted stitch-n-glue hull last year and it has shown no signs of wear. Just as a side note I also used a piece of dynel for under my heels.

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