A blog about SCAMP (Small Craft Advisor Magazine Project) boats. Covering the build, sailing the boat and the scamp community that has formed around this little portly boat.

Sunday, September 21, 2014

Rudder and centerboard glue up

When we were in Port Townsend, I bought the foil kit. Essentially, it was 2 mirror image pieces cut by a CNC mill. When placed together, they form the foils.

However, I didn't have any weight. The suggestion is 2 lbs in the rudder and 22 lbs in the centerboard (!).
I found a local place that sells 1/2" lead plate. I went down to their shop and got 24 lbs of lead. it was about 6.5" wide and 18" long. It was easy to do the math and know that to get 2lbs, I had to cut 1 1/2" of lead. I pulled out the jigsaw and cut it. I was told by the guy at the shop that lead doesn't really have a vapor pressure (like mercury) and that all I had to do was wash my hands after handling the lead.
Still, he gave it to me in a plastic bag, which I thought was good.

Lead really is weird stuff. Extremely heavy.

I measured and routed out a 5/16" deep chamber in the rudder halves at the same spot. That was bit tricky. I don't have any pictures, but the trick is to pick a couple reference points and draw a line that is mirrored on the 2 halves. Once you have that, then you can pick an offset on the line and trace your piece of lead. Now the routing is easy.
The rudder glued up

Another shot
The centerboard had a small void that needed some epoxy to fix it. This is marine plywood which is supposed to be void free. After all, you don't want to fiberglass and epoxy a chunk of wood but then when you smash it into a dock, you hit the bubble just right and break open the wood.
From what I've seen the plywood definitely does have voids, but they are generally pretty small and easy to fill.
The centerboard had a void. I fixed it.

The lead
I eventually did the same trick with the centerboard and routed out a chamber and glued together the 2 halves.
If you do this yourself, I recommend easing the edges really well. You need to fiberglass this around the outside and over the edges. If you have any square edges, you will get bubbles under the fiberglass cloth. In theory you can put a small hole in the bubble and fill it with epoxy, but I've only seen that work once. I found that it was easier for me to cut out the bubble, fill the bubble with thickened epoxy and wait for that to cure. Once it was cured, then I could lay the second layer of glass over the top. I'm sure I lost some strength, but it is in very small spots.
Also, don't worry too much about smoothing out the entire board. You're just going to coat it in fiberglass anyway.
Unless you are going to finish it clear. If you do that, then you'll want to take more care.

However, my work is horrifying. I don't want to finish these clear, I think they'd end up looking just too nasty.

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