Interesting, I'll post a better shot of the keel this evening. It is a rather substantial unit. This boat came with a sail rig, which the build record does not mention. I wonder if the keel was added later to increase sailing performance? This boat lived on Lake George, Ny., and draft was likley never an issue.
Douglas, If I understand your description of the sponson canvasing on Peterboroughs, this is not like that. Looks to me like the sponsons were on, and the canvas draped over the entire hull, including sponsons, and then that sub-sponson strip was scewed into place pulling the canvas tight up below the sponson. The canvas appears to be continuous under the wooden strip, and on around the sponson. Not sure if it was filled before or after the wood strip was placed, yet.
That said, I won't really know until I get that wood strip off.
I have no idea what the sub-sponson strip is made of at this point. The build record indicates CS grade - spruce and ash.
Interestingly, the old town catalog page I have that shows a sqaure stern sponson model does not have the wood strips below the sponson. Never noticed that!