For that last point about AI mob ships, I was thinking of this sort of procedure:
- A naturally spawning mob would be teleported up into a random y-coord in the air above the ocean.
- Then a ship-like structure is formed around the mob, with space for it to stand and walk around.
- When the mob moves in the xz plane, the structure is cardinally moved around with it so that the mob stays in centre. Neither the structure nor the mob will be able to move vertically.
- If the structure collides with something, like another ship, building or floating island, the blocks that make up the structure will disappear.
- Killing the mob (either directly or by destroying the platform it is standing on) will stop the ship from moving. Destroying other parts of the ship will grant materials and money.
For the ship designs, I was also thinking:
- UFO Creepers
- Zeppelin Zombies
- Stealth Plane Phantoms
- Mooballoons