It seems a bit like how old merchant ships ''reqruited'' sailors(at least the V.O.C. and W.I.C): go to a bar, search for able bodied men, get them drunk, promise a good job(fortune fame, that sort of stuff), make them sign a contract(a simple X could suffice becasue not many commonfolk could write their name), kidnap them(''legally'' of course), put them in a prison until it is time to board the ship and then force them to enter the ship and work as a sailor.