In Fall 1943, ComSubPac initiated the Navy's first wolfpack. Momsen drilled his captains and their executive officers in tactics, planning to have three boats act in company, one boat making the first attack on a convoy then acting as "trailer", while the other two attacked alternatively on either flank afterward. He also developed a simple code for use on Talk Between Ships (TBS). The pack consisted of Edgar McGregor's "Shad", experienced skipper Dave White's new "Cero", and "Grayback", fresh from refit in Mare Island (and with one of the Submarine Force's first deck gun), under newcomer John Moore. Momsen, without any combat experience, flew his flag in "Cero".