Went on a private booking from Pier 40 in SF under the Golden Gate and back toward Sausalito, then under the Bay Bridge to see the new span. The crew could not have been nicer or more gracious. And the heads were more comfortable than some of the land-based restrooms I've been in recently...
Caveats: ladders are very narrow. May not be easy going for larger people.
Children under 6 not allowed.
Bundle up! The bay winds get chilly.
To echo what others have said: if you get a chance to sail aboard the USS Potomac, GO.