Pegasus Bay, earlier known as Cook's Mistake, is a bay on the east coast of the South Island of New Zealand, to the north of Banks Peninsula. Pegasus Bay takes its name from the brig Pegasus, a sealing ship that was sailing from Hobart to London via the sealing islands and was surveying this part of the South Island in 1809. Attempting to sail into …Pegasus Bay, earlier known as Cook's Mistake, is a bay on the east coast of the South Island of New Zealand, to the north of Banks Peninsula. Pegasus Bay takes its name from the brig Pegasus, a sealing ship that was sailing from Hobart to London via the sealing islands and was surveying this part of the South Island in 1809. Attempting to sail into Gore's Bay shown on Captain Cook's map between the supposed Island that Cook had named after Banks, the crew discovered a mistake in Cook's chart and found the island was a peninsula connected to the rest of the South Island mainland by a low-lying isthmus. Fortunately they discovered this before trying to pass between the supposed island and the mainland before dark while approaching from the north and were still in about 27 metres of water. Captain Chace and his first officer William Stewart, who had also surveyed Stewart Island on the same journey, were reported in the Oriental Navigator in 1816. Charts made of this part of New Zealand from the 1809 survey give the names Cook's Mistake or Pegasus Bay to this large bay.