The U.S. Navy has ordered a $4.6 million investigation to analyze the effect of such an underwater blast on ships and submersibles within range.

Research over the years has concentrated on the dramatic and destructive impact of the water on vessels in the range of an underwater blast, which can often be deadlier than effects of an explosion on the surface or land but largely unpredictable.

The new research by Alion Science and Technology, an employee-owned technology solutions company, will analyze survivability and response of ships and submersibles to a explosion. The research will likely have global implications and also open new opportunities for Alion, other defense-related businesses and the U.S. military.

Alion's brief under the U.S. Navy contract will focus on the effects of underwater explosions, also called UNDEX, on the navy's platforms. The company says its experts will examine submarines, surface ships and associated platforms for the Naval Surface Warfare Center Carderock Division's Survivability and Weapons Effect Department.

"UNDEX incidents pose a different threat to Navy vessels than above-water explosions because of the pressure shock wave generated by a blast below the surface," explained J. J. Waickwicz, Alion's senior vice president and manager of the company's design, engineering and technology group.

"By providing the Navy with UNDEX engineering support, Alion is enabling leaders to conduct physical security assessments of the naval fleet for survivability and long-term performance, helping to extend the fleet's life cycle," Waickwicz said.

Alion will provide engineering and technical support for UNDEX testing, shock qualification and ship survivability programs.

Alion will also develop and validate algorithms for predicting the response of test vehicles, scale models and submarines and surface ships due to UNDEX events and it will develop and validate what it calls "novel" approaches for increasing the survivability of hull structure, systems and equipment in the UNDEX response environment. The contract is to last to September 2014.

The Naval Sea Systems Command's SeaPort Enhanced Multiple Award Contract provides support for U.S. Navy systems that range from weapons to fleet readiness and homeland security to logistics.

The contract supports the Navy Systems Commands, the Office of Naval Research, the U.S. Marine Corps and the Defense Threat Reduction Agency.

Alion has headquarters in McLean, Va., but says it has skilled employee-owners at offices, laboratories and customer sites worldwide.

Questions about the impact of undersea explosions have bedeviled defense scientists for some time. The effects of an underwater explosion can depend on a number of things, including distance from the explosion, the energy of the explosion, the depth of the explosion and water depth.

Although U.S. and other nations' nuclear tests monitored the impact of undersea explosions at varying depths, the impact on ships within the range on an explosion is an ongoing study. An undersea blast can create huge walls of water and bubbles filled with high-temperature air and other dramatic changes in the ocean.

The resulting shock waves can deliver devastating damage to vessels in the vicinity and decimate marine life.