hi mate your best bet will be to get a good admiralty chart of the area from a locl chandlers this will show any wrecks and features on the sea bed then all you do is transfer the numbers to your gps and go out and find the feature you want it will probably be in a slightly different position to that shown on the chart so be prepared to search around a bit when you find it plot it accuratley on to your gps and you will find it first time every time in future good luck