JEM Watercraft

Yep, here's another builder's log for the Merrimac. I'm a builder in Calgary trying to finish my Merrimac before the river freezes over. I'm only familiar with cardboard-and-duct-tape construction, so this will be my first stitch-and-glue boat. Hopefully it will last a little longer than those cardboard boats.

I've cut the boards and the epoxy finally arrived, so now I'm getting ready for the butt joints. I was going to just glass the joints, since this would seem to be lightest, but I noticed the instructions later say that ribs might be necessary on the bottom to reduce oilcanning. Would it make sense to use wooden butt blocks on the bottom panels only, so these ribs would not be necessary?

simple answer:

Yep!



Add any ribs AFTER you've paddled her a couple times. You may not need the ribs at all.

Good, I guess for now I just have to worry about whether to use the butt blocks, and how many.

My bottom panels are a bit curved already, since I cut them out of a sheet that got left out in the rain a bit (oops). The curve is almost enough that I think it could result in the bottom of the hull having a smooth curve from side to side rather than an angle. I expect it to be safe to barge ahead, but could I be terribly wrong?

Welcome aboard. At the rate I'm going, I'll soon be reading your build log for ideas on how to complete my Merrimac
- Hank

The bottom panel is bowed up down the longitudinal centerline? If so, position the bow so it faces down and you should be ok.

If it were me, I'd consider a different piece of wood.

Looking down the longitudinal centerline, you would see a smiley. I'll try to post photos tomorrow.

I just did two of the butt joints first to try to get the idea of the thing.

This middle panel looks pretty good to me, I used the tape trick I saw in Hank's log. I could probably get closer to the seam, I suppose.

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This one looks worse to me. The wood panels are about 1/8" apart near the top, 1/16" near the bottom. How wide can these seams be and still be strong?

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Here's my warped bottom panels, I think I'll just use them as is.

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A couple people on the forum suggest doing the fiberglass bit immediately after the wood flour here. I suppose I could then still put weights on top of this to keep the joint flat?[/url]

the gap between the panels will depend on how you cut the panels and how well you're following the QA drawings.

Gap up to 1/8" is ok.

For you slightly warped panels, I think if you hold them flat, glue them, then apply the glass or butt block, you should be fine.

Great, thanks for the advice, Matt!

Hey, what can I do with the leftover plywood scraps? Would it be at all usable for the decks or outer frames?

only limited to your imagination!

But stick with the minimum dimensions given in the plans. So if you need thicker, laminate the pieces with several layers.