Thursday, January 20, 2011

Glued Lapstrake Plank Repair

Since we've spent some time lately looking at modern plywood/epoxy construction, it might be helpful to see how repairs are accomplished with this building method.

In traditional wood boat construction care is taken to insure that future repairs can be made without compromising the structural integrity of the vessel. One of the perceived drawbacks to gluing a boat together as opposed to using fasteners is the difficulty in dissembling the damaged area and resembling with accuracy while also keeping the hull fair.

As we've seen with the design modification of Doryman's rowing shell, there is an inherent tendency for the glued planks to sag once the lap or glue joint is compromised. This is due to the strain on the plank, the lightness of the material and the lack of internal framing.

Last November, a combination of a strong gale and a high tide bashed the St Ayles Skiff built by the Ullapool Coastal Rowing syndicate against the rocks, breaking planks on both sides of the boat. Repairs began immediately and thanks to the efforts of master builder Topher Dawson the glue lapped clinker skiff designed by Iain Oughtred has been rescued.
With a bit of paint she will soon be ready for spring racing off the coast of Scotland.
You can follow the progress of this repair on the Ullapool Coastal Rowing site:

Nice job, Topher!



Bursledon Blogger said...

Michael, there's a lot of deadrise in that skiff of yours, the hull form reminds me of the K1 kayaks I used to paddle when I was a teenager and didn't mind getting wet every time I took it out - was fast when I managed to keep it upright though!!

doryman said...

You are right about that. When I set up the bottom shape, I had a lot of weight in the middle to force the planks flat, but with no building frame they worked their way back up by the time the bulkheads and sides were going on. I carried forth hoping all would work out. By taking the bottom out, hopefully the boat will be more stable, since now it also has less rocker.
No intention of getting wet again. If it doesn't work out this time it may become a trimaran.