Top Secret Barge & Ship
Tied Up At Treasure Island

A formerly top-secret submersible barge is tied up at Treasure Island – waiting to be scrapped along with the once-super-secret craft it holds.

The huge (9-stories tall, 342-feet long, 106-foot beam) thing looks like it was designed and built by a committee of Burning Man devotees. Scabby, but functional.

If you sail by the only hint of it’s purpose is the name “HMB 1” on the bows, and a quick google reveals that stands for “Hughes Mining Barge 1”. It was built in the 1960’s as part of a CIA project to salvage a sunken Soviet submarine from the bottom of the Pacific.

The other part of the plan involved the “Glomar Explorer”, a purpose-built ship with a huge open-water bay called the “Moon Pool”. The mission called for a giant claw (to grab the sub) to be built in secret inside the HMB1, which then carried it out to the Glomar Explorer where it was installed in the “Moon Pool”.


Althought the CIA has never declassified the results, word was the sub broke up on the way to the surface and only part of it was recovered.

The barge reportedly sat at Todd Shipyard in San Francisco until 1982, when the Navy moved it to Redwood City, and used it once again as a sort of mobile garage to build an experimental “Stealth Ship” called the Sea Shadow .

The submersible barge served as the support craft for the Sea Shadow until that project was over. The two were part of the Mothball Fleet up in Suisun Bay for years, until they were finally sold as scrap to Bay Ship & Yacht for a reported $2.5 million.

If you sail up and look through the rear of the roll-up door, you can see the pontoons of the Sea Shadow inside.

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