Scratch build your own. Easy to do. Cut out a basic hull shape from a thick balsa beam or foam. sand it back a bit and then clad with thin plastic card or cardboard. Sewing pins will hold the cladding in place and double as rivets. You can scribe planking on to the deck if you fancy. Model ship makers sell all kinds of nautical impedimentia in various sizes like anchors, davits and the like. Anchor chains are readily sourced in craft stores. Small washers bought at hardware outlets make great scuttles/portholes.
I built a three foot long Sand Pebbles type gunboat doing just this many moons ago. Got rid of it when I moved house otherwise I'd have been happy toshow you what you can do with not a great deal of effort.