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Sea Shadow (IX-529) is an experimental stealth ship built by Lockheed for the United States Navy to determine how a low radar profile might be achieved and to test high stability hull configurations which have been used in oceanographic ships.


Sea Shadow was built in 1984 and used in secret but normal service until her public debut in 1993, to examine the application of stealth technology on naval vessels. In addition, the ship was designed to test the use of automation to enable the reduction of crew size. The ship was created by the Defense Advanced Research Projects Agency (DARPA), the U.S. Navy and Lockheed. Sea Shadow was developed at Lockheed’s Redwood City, California facility, inside the Hughes Mining Barge, which functioned as a floating drydock during construction and testing. She is sometimes referred to as “USS Sea Shadow”; however, this designation is inappropriate as she was never a fully commissioned ship of the U.S. Navy.

Sea Shadow has a SWATH hull design. Below the water are submerged twin hulls, each with a propeller, aft stabilizer, and inboard hydrofoil. The portion of the ship above water is connected to the hulls via the two angled struts. The SWATH design helps the ship remain stable even in very rough water of up to sea state 6 (wave height of 18 feet (5.5 m) or “very rough” sea). The shape of the superstructure has sometimes been compared to the casemate of the ironclad ram CSS Virginia of the American Civil War.

The T-AGOS 19-and-23-class oceanographic ships have inherited the stabilizer and canard method to help perform their stability-sensitive surveillance missions.

Sea Shadow has only 12 bunks aboard, one small microwave oven, a refrigerator and table. It was never intended to be mission capable and was never commissioned, although she is listed in the Naval Vessel Register.


Type: Stealth ship

Displacement: 563 long tons (572 t)

Length: 164 ft (50 m)

Beam: 68 ft (21 m)

Service History

Sea Shadow was revealed to the public in 1993, and was housed at the San Diego Naval Station until September 2006, when it was relocated with the HMB-1 - inside which it still resides - to the Suisun Bay Reserve Fleet in Benicia, CA. The vessels are available for donation to a maritime museum.

Sea Shadow was also the inspiration for the stealth ship in the James Bond film Tomorrow Never Dies. Since 2006 the U.S Navy has tried to give the Sea Shadow away but as of February 2009 nobody has taken the offer.

Not having found any viable offer to take in the Sea Shadow by June 18th, 2011, the Navy finally decided to set it for “dismantling and recycling”. As of June 2011 the Sea Shadow is still being stored inside its barge at Suisun Bay awaiting its fate.