SS British Chivalry and the boundary between sinking a ship and a war crime

The video distinguishes the common wartime practice of using a submarine's gun to finish a torpedoed ship from attacks on people who had abandoned it. After a torpedo struck British Chivalry's engine room, I-37 surfaced, shelled and torpedoed the ship again, and took Captain Walter Hill prisoner. The submarine then circled the lifeboats for two hours while firing on survivors, killing or mortally wounding more men. The remaining 38 survivors drifted for 37 days before rescue by the cargo liner Delane. The later tribunal case against Lieutenant Commander Nakagawa did not include his earlier sinking of the hospital ship Centaur, which was connected to him only decades later. The atrocity is documented in detail, but it should not be turned into an uncritical description of every submarine action.