Both Popular Mechanics and Popular Science magazines published many plans for many kinds of boats back then, also some of the nautical mags did too, specially Rudder.

Glen L and Clarkcraft as well as many kit builders no longer around sold kits. That was 80 years or so ago, not many around that were building back then.

Details in the kits could though be easily changed by the builders, cockpit shape certainly isn't hard to change.

Bill H.