The San Francisco Bay Ferry has released the following information on their web site.
San Francisco Bay Ferry (SFBF) will make every effort to accommodate increased ridership demand resulting from a BART strike. These efforts will include deploying all available vessels, implementing special schedules, extending service hours, providing for onsite (off boat) ticket sales at some locations, and providing customer service representatives to provide information and keep riders informed. Please be assured that we are doing everything we can to serve you. However, some delays are to be expected so we ask for your patience and understanding.
Here is a link to the San Francisco Bay Ferry, Vallejo Ferry Schedule that will be in effect in the event of a BART strike.