Break your vow never to go back to Fisherman’s Wharf. The armies of tourists have thinned out and the weekend’s Wharf Fest has a very tempting Clam Chowder competition. It happens on Saturday from noon to 3. Ten major seafood restaurants will be battling to be anointed Best. You can do your own taste testing though the winners will be decided by serious chefs and local politicos. The Wharf Fest, which includes a Segway obstacle course and climbing walls, is free. Tickets for the Chowder are $15 ($20 at the door).