Underwater Express
Pentagon enlists Northrop, General Dynamics
in quest for 100-knot, supercavitating submarine
By OTTO KREISHER, Special Correspondent
Rapid Delivery for SEALs
Pentagon researchers envision a Sea, Air, Land
(SEAL) team of the future on an urgent mission able to race to a hostile shore in a vessel
capable of speeds of 100 knots underwater, without the
risk of detection or the spine-jarring turbulence associated with the SEALs’ current Mark V surface craft.
That is one of the potential results of a bold development effort launched by the Defense Advanced Research
Project Agency (DARPA). Called the Underwater Express,
the program will examine the possible applications of a
technology that enables submerged objects to overcome
water’s enormous resistance and reach speeds greater than
those that can be attained by most surface vessels.
These hopes for the future are based on supercavitation, which relies on the formation of a bubble of air
around a submerged object to divert water away from
its skin, cutting friction or drag by 60-70 percent.
The concept of supercavitation is decades old, but
has been utilized in the past only for weapons, such as
torpedoes, with diameters measured in inches. In the
1980s, for example, the Soviet Union developed a torpedo called Shkval, or Squall, that supposedly could
achieve speeds of 200 knots.
But the DARPA program is hoping to achieve supercavitation with an underwater vehicle that is 8 feet in
diameter and weighs 60 tons.
“The intent is to determine the
feasibility for supercavitation technology to enable a new class of high-speed underwater craft for future littoral missions that could involve the
transport of high-value cargo and/or
small units of personnel,” DARPA
said in its proposal.
The developmental project “must
culminate in a credible demonstration at a significant scale to prove
that a supercavitating underwater
craft is controllable at speeds up to
100 knots.”
To pursue that objective, DARPA awarded research and
development contracts in early November to General
Dynamics’ Electric Boat division for $5.7 million and
Northrop Grumman’s Electronic Systems for $5.4 million.
To indicate the scale of the technological leap
DARPA is seeking, Gene Cumm, Northrop’s business
development executive on the program, said, “
supercavitation is to an underwater vehicle what the jet
engine was to a propeller airplane.”
The contracts fund separate 13-month developmental efforts with the potential for two subsequent 15-
month phases that could increase the total value to as
much as $45.8 million.
DARPA’s presentation to prospective contractors said it
was “likely to have only one team go forward to Phase 2.”
The first phase “will focus on stable cavity generation and sustainment by examining supercavitation
physics and the interactions between the cavity and
body,” according to DARPA’s proposal. The contractors
will develop a system concept for the 8-foot diameter
notional super-fast submerged transport system “so
that appropriate scale models can be designed” for
eventual testing and demonstration. In addition, an
initial concept design of a control system for all vehicle operating conditions is necessary.
Able to dash to an objective, a super-fast sub would lower the
risks of detection.
■ DARPA recently invested $11 million in seed money to launch
the project, but 100-knot subs are probably decades away.
■ The supercavitation concept is an old idea employed by the
Soviets in the 1980s.
■ A key challenge: detecting obstacles and controlling a 100-knot sub
surrounded by an air pocket, which renders current sensors useless.
