At least it isn't on an engine cooling intake. Had a fellow sail club member recently tell me about the time a gate valve failed on a boat he was on, on the engine raw water intake. IIRC, the alternator bracket failed, the alternator fell off and broke off the raw water intake's gate valve's handle. They jury-rigged an alternator bracket (they were "at sea"), but did not realize that when the gate valve's handle was broken off, the gate fell closed. Luckily, it turns out impellers are usually tougher than we give them credit for.