Mortar ship? what a joke, imagine being a small company in a small island, it's all ok, you managed to have your island even when now there's less claimable, and you managed to defend it somehow even being outnumbered, how are you supposed to defend an island, when they can mortar almost the whole island, in small island case? it makes 0 sense in my opinion, and in naval battles it's pointless, nobody stays still in naval battles, so it's just a weapon for griefers or megas that wants an easy way to have more islands. Just think it a bit, you'll find it's senseless.