Currently explosions ignore them.

What sort of damage do you mean? Like the ship falls out of the sky? Some of the blocks get removed as though it were a physical stationary block? This would require a lot of new code to find the blocks that were potentially affected by explosions and then treat them like Minecraft does. Easiest would be to just /kill the ship in an explosion (and I bet you could do this using KubeJS), but I assume you don't want that.

Thanks for the response:

So I actually discovered after posting this that vanilla explosions DO damage the ship, it's just that specifically explosions from Crayfish's Gun Mod don't (the bazooka in that mod can normally destroy blocks)

If this is something that's not possible to do on your I understand and I appreciate the consideration.

I find Prelaw's Blocky Siege to be great for putting cannons onto the ships, and they will damage other ships.