Forget white whales. The objects of pursuit off Nantucket's shores are bluefish and striped bass. You can buy tackle (a 10-foot spinning rod is about right) and bait on the island, and even hire a guide. Then make your way to the beach (you'll need a 4x4 to reach Great Point and Smith Points, a pair favored by locals), but you can walk to Dionis, Pebbles, and Surfside beaches. Then, like Ishmael, cast your fate to the wind.