The Hughes Mining Barge (HMB-1) was originally developed by the CIA to salvage the Soviet submarine K-129 from the ocean floor. It then had a second life 25 years later as the hanger for the Sea Shadow . Then they were both put in mothballs in the Suisan Bay fleet. Someone broke in and photographed it. http://scotthaefner.com/beyond/mothball-fleet-ghost-ships/ The Sea Shadow was sold for scrap to Bay Marine for somet…
It's docked at Bay and Ship right next to the ferry terminal on Alameda. Here's a picture I took of it [1].
If you're in the Bay Area, it's probably not worth making the trip out there for just the ship, but it's neat to walk around the old naval base close to there, and I'd recommend a stop off at Rock Wall Wine Company along Monarch St. There's a spacious outdoor area with a very unique perspective of downtown San Francisco.