WASHINGTON — Submarines are fighting for relevancy in the new, lower intensity warfare that is defining modern conflict. Means of gathering intelligence and fielding small Special Forces teams are the assets most needed to fight terrorist groups and state-sponsored asymmetric military actions. But adapting a vessel designed for the Cold War to have real use these days takes some creative design.

We saw first-hand evidence yesterday at this sea-power tech conference of the Navy trying to do just that, by converting older Ohio class nuclear missile-armed submarines to carry Tomahawk cruise missiles. In most conversions, all but two of the 24 tubes have been fitted with multiple all-up round canisters, swapping the single ballistic missile per tube for seven Tomahawks, for a total of 154 cruise missiles per sub. The remaining tubes are reserved for the quiet, underwater deployment of Special Forces operators.

In case conventional weapons aren’t enough to ensure that subs remain relevant, General Dynamics' Electric Boat and Northrup Grumman are pitching the Navy on new gear for Ohio class launch tubes (pictured above), including a long arm that extends out of the tube to deploy SEAL team-delivery vehicles (or swimmers) or unmanned underwater drones. The tubes can also be installed with a flexible payload module—a one-piece delivery system that can be configured to field undersea sensors, future global strike missiles or unmanned aerial vehicles.

Underwater vehicles that can be launched from submarine tubes are also seen as standard gear for future subs. One of the more novel designs is Saab's SUBROV (pictured at right). A sleek, yellow underwater robot masquerading as a torpedo, the SUBROV is controlled with a single joystick, connected by a fiberoptic or cable tether. It can be outfitted with cameras to inspect the hull, sonar to search for enemies, electronic warfare devices to confuse them, and a loop of cable that allows the rover to pick up and return items to the torpedo tube. The Swedish Navy had already bought a handful, and now Saab is now seeking U.S. Navy interest.

A smarter, untethered system from Boeing brings autonomy to underwater drones, expanding the missions a submarine can undertake. Boeing's AN/BLQ-11 system (pictured at right, bottom) uses GPS guidance and collision avoidance software to enable the drone to navigate shallow waters as it collects intelligence, scans with sonar and maps underwater terrain. Fired from a torpedo tube rather than a missile tube, the drone was tested last year on the USS Oklahoma City. One drawback: The 2700-pounder requires a reconfigured launch tube to handle its mass. —Joe Pappalardo