7 June 1780 the two largest ships of Gibraltar, HMS Panther and HMS Enterprise, were targeted within Gibraltar's harbour by Spanish fireships. Warning shots from Enterprise alerted the garrison and soon an intense bombardment slowed the fire ships. A few were sunk but the others carried on. The Spanish fleet waited just outside the harbour for any British ships trying to escape, so seamen from Panther and Enterprise set out in longboats, intercepted the fire ships, and towed them off course. Second naval relief Throughout the second winter the garrison faced foes, elements, disease, and starvation. By March the situation was serious: the garrison and civilians were on weekly rations and in need of a large supply. For the Spanish the blockade was working, with the few small ships that slipped past the blockade carrying insufficient supplies. On 12 April 1781 Vice Admiral George Darby's squadron of 29 ships of the line escorting 100 store ships from England entered the bay, despite the Spanish fleet. The Spanish, frustrated by this failure, for the first time in the siege opened up a terrific barrage while the stores were unloaded. Although they caused great damage to the town, the South Mole where the ships unloaded their stores was out of their reach. The civilian population of about 1,000 sailed with Darby for England on 21 April, leaving the garrison with fewer mouths to feed and allowing them to operate more freely. Again the fleet left without hindrance during the night and slipped past the blockading Spanish fleet. Provisions for the garrison were now plentiful, including black powder, guns and ammunition as well as food and other supplies. The French and Spanish thus found it impossible to starve the garrison out. They therefore resolved to make further attacks by land and sea and assembled a large army and fleet to carry this out. In addition, the Spanish built a succession of new batteries across the Isthmus: soon there were four of them each containing around fourteen guns. There were also the preexisting San Carlos, San Felipe, and Santa Barbara batteries, each containing around 24 to 27 guns. On 9 June, the British gunners hit a major Spanish magazine, which exploded. The main explosion was followed by a host of minor ones, as expense magazines, subsidiary stores and shells blew up. The Spanish lines were in pandemonium as the troops struggled to put out