Kilantringan, west off B738 a few miles north of Port Patrick, following signs to lighthouse, has the most wonderful looking swell coming in to a sandy beach and is used by surfers. It might work for windsurfing in SW, but is a bit sheltered by the headland at Black Head where the lighthouse is situated and has fingers of rock jutting into the sea at high tide. Several miles of beach. There is a 5 knot tide round the headland.
Port Logan can be a good sail on B7065 in a SW, but watch the dumping waves &, set off from behind the lovely old harbour with brazier light-house and guarde loo!. Alternatively, from the north near the rocks. Not for the inexpert, because if has hills all round, for there to be any wind it must be too onshore for comfort, but it is a truly beautiful spot to sail. Visit the Fish Ponds & there is a small hotel.