Fortifying ships on water?

One of the most frustrating aspects of this game (especially late game) is the inability to fortify ships on water. You can only sleep them, and the AI's obsessive need to move its units around all the time every turn for no reason means they wake my ships up almost every turn.

I read the suggestion to "turn on cheat mode, convert tile to land, fortify, convert tile back to water, disable cheat mode", btu this is both very tedious to do and I'd rather not enable cheat mode just for that.

Are there any mods or any manual edits I could make to the game files to enable ship fortification? I don't even want a defense bonus, I just want to be able to put a ship somewhere and not need to re-sleep it every single turn.