Sea Shadow
Characteristic
Power Plant Diesel electric
Available Design Details SWATH (Small Water Plane Area Twin Hull)
Length, 164 feet;
Beam, 68 feet;
Draft, 14.5 feet;
Displacement, 560 tons;
Crew, 10
Purpose Technology demonstration platform
Status Reactivated in 1999 as a DD-21 technology test platform
Start Date Early 1980s
Terminal Date Placed in dry dock in 1994, reactivated 1999
Sea Shadow focused on evaluating stealth technology on surface vessels. It also
served as a platform for the integration and evaluation of other new technologies,
including ship control systems, structures, automation for reduced manning, sea keeping,
and signature control.7 The focus on stealth technology made Sea Shadow a highly
classified program managed by DARPA, the Navy, and Lockheed Martin Missiles and
Space Company.
Development Chronology
The idea for a stealthy naval surface vessel occurred to Ben Rich in 1978, when he
was Director of the Lockheed Skunk Works. The project photographer working on the
model for the first stealth aircraft complained about defects in a recently purchased
Polaroid camera. Rich wrote that the photographer told him:
I’ve been taking instant view shorts of the stealth model, and I’m getting
very fuzzy pictures. I think I’ve got a defective lens,” he remarked. I
[Rich] slapped my head, knowing we had accidentally stumbled onto an
exciting development. “Time out! There isn’t a damn thing wrong with
your new camera,” I insisted. “Polaroid uses a sound echo device like
sonar to focus, and you are getting fuzzy pictures because our stealthy
coatings and shaping on that model are interfering with the sound echo.8
The Skunk Works immediately began investigating stealthy submarines
undetectable to sonar. They purchased a small model submarine, put faceted fairings on
it, and tested it in a sonic chamber. These changes reduced the sonar return from the
model sub by three orders of magnitude, a result that Rich termed “as rare an occurrence
as an astronomer discovering a new constellation.” 9 Lockheed designed a stealthy sub
with the traditional cigar-shaped hull “shielded by an outer wall of flat, angular surfaces
that would bounce sonar signals away and also muffle the engine sounds and the internal
noises of crewmen inside the vessel.” After running acoustical tests Rich took the results
to the Navy submarine R&D office, where they were rejected.
Lockheed’s involvement in Navy stealth might have stopped there had it not been
for a company engineer just back from a Pearl Harbor business trip who mentioned to
Rich that he had seen a catamaran-type ship that the Navy had built experimentally. This
prototype SWATH (Small Water Area Twin Hull) ship was proving to be amazingly
stable in heavy seas and was considerably faster than a conventional ship. Rich felt that a
catamaran SWATH ship held real promise as a model for a stealthy surface ship, so he
presented the idea Dr. William Perry, the Under Secretary of Defense for Research and
Engineering. Rich suggested they could test several stealth-related technologies on the
ship. Dr. Perry agreed and arranged for DARPA to issue a study contract.10 This small
contract was aimed at developing a workable model catamaran and testing it against
Soviet X-band radar. Rich wrote, “Shape was the key to defeating Soviet radar. Coatings
accounted for only 10 percent effectiveness in deflecting radar. The rest was quietness of
a vessel’s engines and minimizing its wake.”11 The Lockheed team developed a model
with a pair of underwater pontoon-type hulls that propelled the ship with twin screws. It
had good stability in rolling seas and produced very little wake.
The subsequent prototype resembled the F-117A stealth fighter (see Chapter I)
with a series of severe flat planes at 45-degree angles. “Diesel-electric propulsion would
power the ship’s counter-rotating propellers. Careful shaping of the pontoons and the
propellers cut down sharply on noise and wake.” In addition to stealth design structure,
Sea Shadow had an “A-frame” design to reduce the surface area of the ship coming in
contact with the water in an effort to reduce the ship’s signature. The SWATH
configuration incorporated two submerged pontoons that supported the upper structures
while increasing ship stability. It also minimized the ship signature through the sloped
design of the hull.
The Sea Shadow concept was focused on the Soviet Blue Water threat—
specifically the Soviet long-range fighter-bombers that were threatening the US Navy
with new look-down, shoot-down radar-guided missiles. The Navy’s Aegis missile
frigate was being procured with the objective of destroying incoming cruise missiles.
Lockheed argued that its ship would cost only $200 million (compared with the billion
dollar Aegis frigate), would be armed with Patriot-type missiles that could attack the
cruise missile carrying bombers, and would be invisible to the Soviet radars. The ship
“could be sent out hundreds of miles ahead of the carrier task force to shoot down the
Soviet attack aircraft before they got within missile range of the fleet.”13
On reviewing the test data, Dr. Perry ordered the Navy to fund R&D of a stealth
ship. Perry was adamant about proceeding although the Navy was highly resistant. In a
meeting with the Chief of Naval Operations he responded to the Navy’s reluctance:
“Admiral, we are going to build this ship; the only question is whether the Navy is going
to be part of it.”14 Perry tried to soften the blow by stating that the funding would not
come out of other Navy ships.
The Sea Shadow was constructed in modules in several shipyards and then
assembled inside a huge submergible barge. It was made of very strong welded steel,
displaced 560 tons, and was 70 feet wide. The ship had a four-man crew—commander,
helmsman, navigator, and engineer.15 These figures went up over time and subsequent
tests carried up to 24 people—still far less than on normal Navy craft.16
A number of impediments to development were reported. Many of these appear
to have been bureaucratic. In his book, Rich is scathing in his evaluation of both Navy
resistance to new concepts as well as the approach of Lockheed’s own shipbuilders. In
recent interviews, Ugo Coty, the chief Skunk Works designer of the Navy stealth concept,
reported that he had shared many of Rich’s concerns about the development project.
Coty said that a major problem is that the Navy “never builds experimental ships.”17
Instead, the Service builds the first ship of a class of ships—and may not build the rest of
the class. Thus the people Rich had called “bureaucrats and paper pushers” in his book,
were simply a typical part of a standard shipbuilding program, and to them the demand
for paint lockers (on a ship that would not be regularly chipped and painted) made perfect
sense.
Once constructed, the Sea Shadow was towed to Long Beach to begin its tests off
Santa Cruz Island. All tests were at night against the most advanced Navy hunter planes.
Rich reports that tests were extremely successful:
One typical night of testing, the Navy sub-hunter airplanes made fiftyseven
passes at us and detected the ship only twice—both times at a mileand-
a-half distance, so that we would have shot them down easily long
before they spotted us. Several times, we actually provided the exact
location to the pilots and they still could not pick us up on their radar.18
The tests continued over 2 years. All reports indicate that the Sea Shadow
performed well.19 Nevertheless, although individual technologies were applied to Navy
ships, the ship itself was never introduced into the fleet. Rich’s view was that the
admirals who ran the surface fleet were against it. He wrote that they told him the design
was too radical. They told him, “If the shape is so revolutionary and secret, how could
we ever use it without hundreds of sailors seeing it? It’s just too far out.” He noted,
“Although the Navy did apply our technology to lower the radar cross section of their
new class of destroyers, we were drydocked before we had really got launched.”20
When Dr. Perry left office, the next administration’s OSD Comptroller reduced
funding for the DD-51 in the following year’s budget request, which the Navy interpreted
as redirecting funds to pay for Sea Shadow. In response, Chief of Naval Operations
Admiral Hayward cut the program out of the budget. Coty went to Hayward and asked
why and was told it was because the Navy Program Manager was asking for too much
money. The PM had submitted a request for missile development to arm the new ships
and everything to go with them. In Hayward’s view these requirements had come “before
the ship had even been shown to be stealthy.”21 Coty said that after a fast reeducation of
the new Administration, money was restored. But stealth supporters such as Rich and
Coty believed the Navy brass largely disapproved of the development.
Sea Shadow was deactivated from 1987 until 1993, when it was reactivated for
additional equipment testing. In 1993 and 1994, it was openly tested, serving as a
platform for testing several concepts including combat systems developed by Lockheed
under contract with DARPA. Two Combat System prototypes, the Automated Combat
Identification System (ACIDS) and the Tactical Action Advisor (TAA), were tested. The
ACIDS was a decision aid to automatically identify air and surface tracks based on sensor
and intelligence information as defined by the tactical operators. The TAA system was a
decision aid to support a Tactical Action Officer or Warfare Commander. The testing and
demonstration of both the ACIDS and TAA prototypes were a part of the DARPA-funded
High Performance Distributed Experiment (HiPer-D) program, and the versions of the
ACIDS and TAA prototypes that were tested used software technology funded by
DARPA for civilian and defense applications.22 The testing was again reported to be
successful.
According to Lockheed representatives, the tests also proved out the use of
commercial-off-the-shelf (COTS) technology in the systems and were the basis for using
COTS in the Aegis system. As a result, each of the developed Aegis employed more
COTS in its computer hardware and software, and the Aegis 71 is now fully COTS.23
The Sea Shadow was once again placed in lay-up status in 1994. Although it did
not enter the fleet, its design did contribute to follow-on programs like the Arsenal Ship
and the DD-21 as well as other ships. The ship was reactivated in 1999 in anticipation of
using it to test new technologies being developed for the DD-21.24 Specifically, the Navy
said that the Sea Shadow would help support risk reduction efforts for the DD-21 and
other future ships and facilitate the testing of automation systems and information
technologies that are key to reducing manning and increasing ship survivability.25 Tests
have focused on design concepts for the destroyer. The Sea Shadow continues to be used
to test DARPA concepts, including a platform for DARPA’s High-Performance
Distributed Computing experiment.26
Sea Shadow Technology and Acquisition Innovations
Following are some of the processes/technologies tested on Sea Shadow:
• Command and Control
o Improved ship control
o Automated ship control
o The Communicator
• Materials and Structures
o Structural design for reduced signature angled surfaces, rounded edges, and
a single, lightweight mast
o Advanced structures
o Twin hull construction employing a unique hull design with two thin struts
to support the deck structure and two submerged, submarine-like pontoons
known as the Small Water Plane Area Twin Hull (SWATH)
• Propulsion
o Jet, counter-rotating engines (jet not installed, used diesel instead, but
proved stealth principal of the counter-rotating engines)
• Sustainment
o Automation for reduced manning
• Weapons
o Automated Combat Identification System (ACIDS)
o Tactical Action Advisor (TAA)
Several key technologies related to sea-based stealth were developed and
demonstrated, as was SWATH technology; new communication, command and control
approaches; and automation for reduced manning. From all evidence, the stealth
component worked very well. This was apparent in the early 1980s, but only slowly
penetrated the Navy leadership. Reduced manning was also fully demonstrated.
However, such reductions continued to be opposed by many among the uniformed Navy
leadership who worried about the ability to respond to battle damage with much reduced
crews.27
Summary
Overall Sea Shadow has proven to be a very valuable test vessel. DARPA played
a significant role in its funding and development. The Program demonstrated many of the
problems that are likely to occur when DARPA works with the Services to introduce
novel technologies that might have significant impact on the Services’ force structure and
operations. The stealthy Sea Shadow immediately came into competition with other
Service priorities (Aegis). It had no powerful Navy advocate. It ran up against an
acquisition process that made it difficult to succeed (e.g., Was it the lead ship of a new
class rather than a demonstrator?). And, with Dr. Perry gone, it had no powerful advocate
anywhere in the DoD. It sank into the background. Still, it is possible to track
technologies developed here to the ill-fated Arsenal Ship, the current DD-21 and today’s
DD(X).
http://www.darpa.mil/Docs/P3698_DARPA_VolII.pdf