Does anyone remember "Nobby" Clarke the signals teacher at Hull Nautical College in the seventies? He was ex Royal Navy and I remember him telling our class that he was actually still employed by the Admiralty. I believe he also taught at Trinity House. He used his home made morse tappers with the lights attached and had all sorts of little quirks and aids to memory. He didn't suffer fools gladly but if anyone could get you through signals he could. A real gentleman who genuinely took it as a personal affront if any pupil failed.