Hoping someone can help with a query I've been asked. A chap I work with is researching HMS Unbeaten as a relative of his died on her when she was sunk. He's got a copy of her log from the National Archives and I've been translating some of the submarine terms for him (he's ex-mob but GS). I'm stuck on 2 terms. One is SPBC which is written on every watch handover and signed by the OOW but I don't know what SPBC stands for. Best guess is Submarine PB Correct but no idea what the PB would mean, Position and Bearing maybe? The other term is MS Routine which seems to be carried out surfaced or at PD..any ideas, think it may be something to do with signals. Any ideas welcome even if it's just best guesses that I can research further.