I know this boat. I bought a bare hull to this design from its backyard builder in 1975. The owner was disappointed with the rough finish. It was ferro cement. (I know, I know, I know!) I paid him CAN$1.00 and it was worth every cent. The surface didn't bother me. I decided I wanted a junk rig and commissioned Jay Benford to draw me up a sail. I ordered a Sabb diesel, 6-8 Hp. with a variable pitch propeller.
While cutting out a piece of the keel to make way for the propeller, i made a sobering discovery. The ferro cement was weak and had a texture like sponge toffy. Apparently, the builder used a formula for cement the incorporated asbestos. It was devised by Fab Aumento, a geologist who determined the asbestos made a significant difference in the strength of the concrete. That was before the big scandal about asbestos.
The builder found this formula so stiff, so difficult to work, he added water. That just isn't done! The water added to cement is meant to bind with the ingredients as part of the final, solid mix. Excess water is left over in the concrete. When it dries out, you get a sponge-like structure. I sold this hull for $1,00 to a friend who sold it for $100.00. The last I saw of it, it was in a backyard somewhere, upside down, bleeding rust.
The motor was placed in my Marco Polo/Teleport. I wrote for approval to Angus Primrose, I think.
I wrote to Jay and cancelled my order and paid for the work done It looks like he finished the plan, and you see it in this thread. Or, it may be another, from scratch.