I didn't have a lathe in my houseboat, but I'm sure it would have been usable if I had. Not underway, but in a protected anchorage or a dock, sure. The main thing would be to fasten it well enough so it wouldn't come adrift in a seaway when not in use. It's a lot of weight to throw around. My Gingery lathe would have been a good choice since all the castings were aluminum, and the whole lathe with motor probably only weighed 50 pounds, but I didn't build it until I was long off the boat.