Has anyone out there owned a boat called a Tropicraft ? They were plywood hulled boats, made in Miami, Florida in the late 1950s and perhaps into the 1960s. A friend of mine owned one back in 1960, and over the next six years we put a lot of miles on that boat. He first had a 40 hp. Royal Scott motor, and then went to a 1962 Johnson 75 hp. motor. The boat was 18 feet long, with a rather wide beam , and it was incredibly rugged, and very stable and seaworthy. My friend showed the boat no mercy in rough water, but it held together admirably for all those years.
Molded plywood hulls were to be the wave of the future....until fiberglass took off and that did THAT in. Many companies bought plywood hull blanks, finished them off, and sold them. Not unlike Yellow Jacket, Tollycraft, and a mess of others we've seen here. Doug Young bought a never been touched hull blank on ebay a few years back for a buck. Dimensions sound similar to yours.
Yes, there were a lot of molded plywood boats being made, prior to fiberglass boats becoming widespread. I've heard of at least one fiberglass boat that was a modified knockoff of a molded plywood boat. There was another method of building wood boats called strip planking, although I've seen two different versions of strip planking. One version used thin strips of wood, about two inches wide by an eighth of an inch thick. The strips were glued and nailed into place in multiple layers to form the hull. Unlike molded construction, however, there was no mold or form involved, but rather the strips were laid over and attached to a frame skeleton. A second version of strip planking, which I saw my father use, consisted of strips of spruce about an inch and a half wide by an inch thick, cut to have a convex top edge and a concave bottom edge. The strips would key into each other as they went up the side of the hull. Just to clarify a point, the Tropicraft boat I mentioned above was not molded, but built from sheet plywood , reinforced with wood framing, and with a plywood floor over the bottom framing. Possibly, such boats were built up from two or more layers of thin plywood , which would make cold bending much easier.