Tuesday, January 28, 2014

Scarfing the garboard plank

It's been a while since my last post, but it doesn't mean that I haven't been busy. Lots of progress in the past few weeks. I'll put up a few posts with pictures to give you an idea.

By the way..."scarfing the garboard plank" is just nautical speak for "tapering and gluing the bottom of the boat together".

Now that all the main pieces of the hull structure are finished, I built the ladder frame and laid out the bottom plank(s). Because the boat is 15 ft long, I have to join two pieces of 9mm ply. Lots of ways to do this, I guess, but the general consensus among Navigator builders is to do an epoxied scarf.

Following others, I went with a 8:1 ratio. So a 9mm plank will have a taper that is 72mm long. In order to do this, I stacked both pieces offset by 72mm. I scribed a reference line across both sheets of ply, and hand-planed them down. Sounds daunting, but really isn't too bad. The layers of ply actually end up providing a pretty decent reference point, as you can see from the pics. The idea is try to get the lines as straight and parallel as possible. When this is done, flip one sheet over. Line them up, and glue with epoxy. Voilá! a 16' sheet of ply of uniform thickness.

Next up...work on the centerboard and centerboard trunk.

Initial planing work

Here you can see the individual layers of ply showing through the tapered planing
Used a piece of lumber as a guide for the plane along the scribed reference line so as not to plane too much
Getting close
Gluing up the scarf. That's a thickness planer being used as a weight to hold down the improvised wooden bar clamp!

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