There are much bigger problems, like drowning, getting bonked by your mast, getting run over by a boat, etc., than getting attacked by a shark. You shouldn't be worried at all about sharks inside the Bay. Sailing far from shore in offshore or sideshore winds can be potentially hazardous in the event of an equipment breakdown. The SFBA strongly recommends sailing with a buddy. In addition we recommend carrying a safety kit, which should include 3 flares, 30' of line, loud whistle and a waterproof strobe.
Many shops sponsor swap meets throughout the season.
The swaps at the beginning and end of the season are usually the biggest. Call of the Wind has online classified section for used equipment.