Our enemy counterpart: large boats, difficult to handle submerged, some twice as big as ours; complicated and inadequate controls; crowded living conditions and a completely foreign sanitation outlook; excessive vibration; inadequate silencing of emergency machinery; wholesale violation of safe submarining construction practices, according to our standards, The wonder was that the Japanese submariners operated at all, much less took their unhandy ships to sea and sank some of our largest men-of-war.