 Between them, the Gambier Islands and Thistle form a chain across the mouth of the gulf between the southern tips of the Yorke and Eyre Peninsulas.As of 2014 the Royal Australian Navy operated an acoustic range in the waters west of Thistle Island, with a small control facility being located on the island itself.The island was named by British explorer Matthew Flinders in 1802, after a terrible accident in which a cutter that was mastered by John Thistle and carrying 7 other men, overturned in choppy seas while returning from the mainland to the ship.