Note: I made the model a tiny bit too big for my Prusa mk4. So I used the MOVE function in prusaslicer to sink it into the plate a little bit. It then printed nicely. It wanted to use supports in the threads, and I was like, sure you do you! It used less than a gram of material, and turned out nice. So that's cool.

If you find that sea life has taken a liking to the hull of your boat, this might help chase them off. 

You need a handle. The bigger the boat, the longer the handle you will need. I have one that extends! Hooray!

The straight version is great for directly carving muscles and barnacles off (don't ask me how I know) the curved one is to help get around the curves of your hull. Tried it out today, worked well.