Army ROV clears underwater ordnance off Hawaii

Instead of human divers, the Army has used a robotic underwater vehicle to help recover and destroy more than 300 pounds of explosives found off Hawaii in an area that was a dumping ground for munitions after World War II.

Working from a barge, operators deployed the remotely operated underwater munitions recovery system (Roumrs) over Ordnance Reef, an area off the Waianae Coast of Oahu.

Equipped with lighting, scanning sonar, and video cameras, the off-the-shelf ROV has force-feedback manipulators that mimic hand and arm movements of its operator. It recovered 74 pieces of exploded ordnance and 2,300 small arms munitions, clearing most of the area, the Associated Press reported.

The device seems to be a modified Comanche ROV manufactured by Sub-Atlantic.

The recovered ordnance was treated in the energetic-hazards demilitarization system (EHDS), a heavy-duty oven that cooks the explosives until they degrade to non-hazardous materials. The resulting scrap metal, if deemed safe, can be recycled.

It has been decades since it was considered acceptable to dispose of unwanted ordnance in the sea, and some of the explosives could not be moved from the seabed due to heavy coral encrustation.

"Because we are concerned with damaging both the coral and the robotic equipment being used, we decided that if the robotics could not free the munitions after a few minutes, without risking damage to the coral, we would leave them in place," J.C. King of the Office of the Deputy Assistant Secretary of the Army for Environment, Safety and Occupational Health was quoted as saying by the Army.

The Army had previously tried to use divers to clear the reef. The experimental ROV effort was the first of its kind and brought together the National Oceanic and Atmospheric Administration, the University of Hawaii Department of Oceanography, and contractors such as Oceaneering International.