A friend of mine was chatting to a local in his pub who claims to be a submariner. He doesn't believe him and asked me if there was a question that he could ask him that would prove that he was or wasn't a submariner. After a bit of thought I came up with "what are the contents of a red cross locker?". I said that most people would assume it was a first aid locker and reply with some first aid stuff. A submariner would reply with a list that included "a chisel ended wheel spanner". So to my question. Is this a valid question for all classes of boats (looking to the old timers here) or can someone come up with a better question that would cover all classes.