Given that one of the most commonly discussed and unpleasant torture methods involves simulating the experience of drowning, I've often wondered why so few people consider inflicting that exact same experience on many enemy sailors by means of missile or torpedo to be even remotely bending the rules of engagement. Granted, the person that fires the fatal shot probably isn't an incorrigible sadist and may even be at imminent risk of a similar fate themselves, but they're still inflicting that suffering with a similar level of intentionality and certainty to a CIA operative with a bucket...