Swim
The second leg of this race will be a swim from Fisherman's Wharf all the way to Alcatraz and back. This swim is ~3 miles long and is through the chilling water of the Bay Area. Not only is it cold, but with the ebb and flow of the tides you will have to fight against the current to swim to the island.
If you are in need of a wet suite for this portion, here is a list of local shops that can rent you one.
Once you complete this leg of the triathlon, you will next move on to the biking leg of the triathlon.