A cold molded boat is a boat with a laminated wood or fiberglass hull. The wood is cut into thin strips about 1/8" thick. these are then bent over frames on a diagonal to get the hull shape. Subsequent layers are added with epoxy resin, on the diagonal running the opposite way so they cross. Essentially the hull becomes a single thick piece of plywood. There is a fiberglass material made in strips called C-flex that is also used to build a boat the same way.
You don't need a mold, so it is good for a one off. However you don't get a molded smooth gelcoat, so finishing the hull is very labor intensive.