@eva1977
Interesting game mechanic for sure. Perhaps there is some sort of in game per use quest that needs to be accomplished to allow for the use of an undead ship.. Meaning you start out as a standard pirate ship and crew and then though a per session quest you can transition into a "Ghost ship" of your apparent ship size.
All of this should require you obey all the "laws" that are of the ghost ship while you and your crew are also classed as "Undead" and even take on some kind of ghostly visible traits that key in other players your character trait just in the same way that the regular skeleton warriors are.
Your player mechanics will also change in suit as a result for the duration that you are "crew" of a skeleton ship.
You are assigned a random skeleton warrior trait, like Metal, Plant, Shadow, etc.
You never run out of ammo and have longer range cannon (just like a skeleton warrior)
You never run out of boards or bananas to use.
You cannot bail water as you have no bucket.
You cannot swim.
You cannot form an official alliance with a living crew.
This would most certainly add some new depth to the game, while keeping the game mechanics consistent.