Kaimusailing

I had an urge to start work on the D4 dinghy, so instead of continuing with grinding on Kaimu’s underbody, I drew dinghy parts on a couple of pieces of 5 mm plywood. This plywood which goes by the name of Revolution is a Chinese product that I have used before for outrigger canoes and a fellow back in Maryland used it for a hard dodger on his ketch. It seems to hold up well in the marine environment, but it needs to be carefully finished with lots of epoxy, 3 coats minimum.
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One sheet of ply had one hull bottom and one hull side drawn on it. The bottom consists of two pieces with a shallow vee. Some plywood dinghies have a flat bottom with no vee, this ends up rowing about as well as an inflatable dinghy, not so good. The other sheet of ply had all the bulkheads, bow and stern transoms, and the 3 seats. At Duckworks website there are several D4 build articles with photos and modifications and one article shows how to nest all the bulkheads, transoms, and seat parts on one sheet of ply. Not much wasted plywood with either of these two sheets.
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The plan is to use these parts as patterns for their duplicates, because two hull bottom pieces are needed as well as two hull sides. These will be cut out of another sheet of ply using a router and following the pattern of the original pieces. The other sheet of bulkheads, etc., also needs to be duplicated because the plans call for 3/8“ ply, or 10 mm, so I will glue duplicate pieces together to make the double thickness.
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The next day I cut out the pieces and found I had made an awful and stupid error. And I made it twice. I must have been tired. I could see that the bow transom didn’t look exactly like the one shown in the plans. I double checked its dimensions several times. I finally concluded that the depiction in the plans must not be a scale drawing. Wrong.
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I first found one of the bulkheads was obviously not symmetrical, so I measured it and redrew it before cutting it out. Then, after all the bulkheads, etc., were cut out I compared the edges of the transoms that would align with the ends of the hull sides and forward and aft edges of the bottom pieces. They didn’t match, not at all. It took a while for me to finally see the mistake. I had used the dimension of the height of the chines from the centerline or keel as the dimension for the height of the hull side portion of the transom. I did this on the stern transom as well as the bow transom. I had to redraw them and cut them out again. They then matched up perfectly with the hull side and bottom drawings.
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Then I cut out the hull bottom and the hull side. I had a pile of offcuts that wasn’t too big, this is an efficient boat plan. My problems with misdrawing parts and having to redo two of them cost me in time, maybe a total of 3 hours extra. I probably have 10 hours into the build so far.
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The image is of the plan for the stern transom. The 4“ dimension fooled me into using it for the side edge of the plan.