12:30
Frank glanced at his watch . It was 12 o'clock . `` Fifteen minutes in which to lay the mines , '' he said to himself . `` They must explode at 12:30 -- '' At 12:10 the submarine emerged from the depth and floated calmly upon the surface of what appeared to be an artificial harbor . Frank and Williams , leaving Jefferson at the wheel and ordering the engines stopped , sprang on deck , carrying two small packages each . These , bound in little tin boxes , were the deadly mines . `` One off here , Williams , '' said Frank , putting one on deck and glancing at his watch .