midnight
We were all dressed in white , with a blue mark on the left arm -- 160 blue-jackets and 80 marines -- and armed with cutlass and pistols -- all picked men . Every man knew exactly what he had to do -- some to attack one part of the ship , some another ; others to go aloft and loose pails , some to the main , and others to the foretop . The admiral sent all the ships of the squadron out of the bay , except his own flag-ship . At midnight we were told off into fourteen boats . A line of booms had been placed across the mouth of the inner harbour , with only a narrow entrance . Just then the admiral 's boat , which led , ran foul of a Spanish guard-boat ; but he whispered to the crew , that if they gave any alarm he would kill every one of them ; so they held their tongues , and we were quickly alongside the _ Esmeralda _ . The Spaniards were asleep , and before they had time to seize their arms , we were upon them , the frigate 's cables were cut , and we were running out of the harbour .