text: As the Americans proceeded slowly, a lookout on Marblehead reported that the starboard propeller was foul of a buoy. The engine was stopped, and the propeller was cleared of the "buoy", which turned out to be a contact mine. The mine was successfully disarmed. Afterward, it was learned that the ships had passed through a field of 18 such mines, or torpedoes, on the trip up the bay and through the same field on the return trip, without injury of any kind. A few days after the attack on Cayo del Toro, the mine field was thoroughly explored, and 14 mines were recovered. Their failure to explode on contact was attributed to mechanical faults, plus a healthy growth of barnacles on the contact levers.
  The minesweeping operation, carried out without specialized equipment, involved two steam launches and two whaleboats from Marblehead and Dolphin. A launch and whaleboat side by side, connected to the other launch and whaleboat by a rope with a chain drag in the center, swept the channel. When the drag met an obstruction, the boats came together and crossed the ends of the drag. The boats were then hauled carefully up to the mine, which was brought to the surface and disarmed. Twice the drag brought up two mines together.