Task: Question Answering
Input (English): Passage: Shackleton's first task, on arriving at the Stromness station, was to arrange for his three companions at Peggoty Camp to be picked up. A whaler was sent round the coast, with Worsley aboard to show the way, and by the evening of 21 May all six of the James Caird party were safe.It took four attempts before Shackleton was able to return to Elephant Island to rescue the party stranded there. He first left South Georgia a mere three days after he had arrived in Stromness, after securing the use of a large whaler, The Southern Sky, which was laid up in Husvik Harbour. Shackleton assembled a volunteer crew, which had it ready to sail by the morning of 22 May. As the vessel approached Elephant Island they saw that an impenetrable barrier of pack ice had formed, some 70 miles (110 km) from their destination. The Southern Sky was not built for ice breaking, and retreated to Port Stanley in the Falkland Islands.On reaching Port Stanley, Shackleton informed London by cable of his whereabouts, and requested that a suitable vessel be sent south for the rescue operation. He was informed by the Admiralty that nothing was available before October, which in his view was too late. Then, with the help of the British Minister in Montevideo, Shackleton obtained from the Uruguayan government the loan of a tough trawler, Instituto de Pesca No. 1, which started south on 10 June. Again the pack thwarted them. In search of another ship, Shackleton, Worsley and Crean travelled to Punta Arenas, where they met Allan MacDonald, the British owner of the schooner Emma. McDonald equipped this vessel for a further rescue attempt, which left on 12 July, but with the same negative result—the pack defeated them yet again. Shackleton later named a glacier after McDonald on the Brunt Ice Shelf in the Weddell Sea. After problems arose in identifying this glacier, a nearby ice rise was renamed the McDonald Ice Rumples.By now it was mid-August, more than three months since Shackleton had left Elephant Island. Shackleton begged the Chilean Government to lend him Yelcho, a small steam tug that had assisted Emma during the previous attempt. They agreed; on 25 August, Yelcho—captained by Luis Pardo–set out for Elephant Island. This time, as Shackleton records, providence favoured them. The seas were open, and the ship was able to approach close to the island, in thick fog. At 11:40 a.m. on 30 August, the fog lifted, the camp was spotted and, within an hour, all the Elephant Island party were safely aboard, bound for Punta Arenas. 
Question: What vessel did MacDonald equip for a further rescue attempt?
Output (English): Emma.