Indeed. It was driving me mad trying to think of where I'd heard that premise before, until I realised they were basically riffing on Chinmoku no Kantai
(Silent Service), the old Kawaguchi manga from the late 80s.
Anyone ever manage to see the anime that was made from the books? It supposed to be quite rare .....
So anime may be dying, but I'll bet TV & Hollywood will still be plundering it decades from now.