Having the same issue with the Gallion (haven't tried the others yet)... When not at water it tosses me a visual error saying you need a water surface. When at water it just doesn't do anything. Large location, tried swimming way out from the shore. Can't get it to place.


Edit: Just read in another discussion that you might have to be standing on a "Dock" from the mod in order to place the ship. Kinda stupid, but if it works then it works.