How do you find an unchrted island in the south-west region in the legend of Zelda the phantom hour glass

well, sometimes people/signs will tell you where a uncharted island is and you mark it down on the map. or you just sail around and find them yourself. One uncharted one that i found in the south-west? Hmmm. try in the botom right corner of the map on the left side of the rock wall. just sail a lot around there. and hour glass is one word