I typically use gridded sheets from a big pad that I purchased at Office Depot for my battlemats. What I did at one point was to simply sketch out a few ship shapes and cut them out of that. Then (because I like stuff that is a bit sturdier) I used some spray glue and put them on foamcore and cut them out of that. Been using them for years.
You're welcome. I, too, like to print them out and put them on foamboard. I also have the Paizo flipmat and wish I had the Dungeon Tile boats, but I don't yet.