Boat of the week 9

Shell never float.

Seen at the Northwest School of Wooden Boat Building in Port Townsend.

A boat in two halves. This is the jig that students use to practise their skills in carvel and clinker (lapstrake given that its in the US) construction.
It emphasises the differences in the two techniques extremely well. The carvel side has stringers to which the frames are then bent (left of picture). On the clinker side the planks are shaped around the forms and the the ribs bent in afterwards (right of picture).
Ive never done this so I speak out of ignorance and conjecture but...
With traditional carvel construction the outside of the hull seems to be two steps removed from the lofted shape. The stringers are bent around the moulds (one step) then the frames are bent around the stringers (two steps). Then the planking is bent around this. And must then be faired. Its a lot of work to get a smooth hull!
In a clinker boat the planking touches the moulds. The picture one the left shows a mould on the right of frame but this is a bit deceptive. In a real boat build the mould is unlikely to be left in during planking. Though it would keep the shape of the shape of the boat and they could be removed one by one as the boat is timbered out (frames or ribs installed).
All that aside what really appeals to me about clinker is the structural redundancy (is that a term?) of it. All those (over)laps create a stiff, strong hull. Add in the ribs and the whole shape is tied together in an almost monocoque structure. The carvel side of this hull looks like its clinging on by its threaded fastenings, its planks barely acquainted.
I was lucky enough to be in Port Townsend on a Sunday when the shop was quiet and spent nearly two hours poring over the boats at the Northwest School but every time I saw something in a finished build I came back to the building jig to see how it was done.
What a great place to go to school.

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