Navy Explosive Ordnance Disposal Mobile Unit (EODMU) 1, tested new unmanned underwater vehicles (UUVs), July 15 in the waters off Oahu during Rim of the Pacific 2010 (RIMPAC).

EODMU 1 is using the waters off Oahu to test new UUVs to replace some of the tasks marine mammals currently perform to provide mine countermeasure operations for the Navy.

EODMU 1 has already replaced some dolphin and sea lion tasks up to 100 meters in depth by using the REMUS 100, a Remote Environmental Measuring Unit by Hydroid Corporation in partnership with the Navy's Space and Naval Warfare Systems Command (SPAWAR).

SPAWAR is testing the upgraded REMUS 600. The UUV can operate in depths of up to 600 meters for up to 70 hours with plenty of areas to apply a wide array of sensors for today's technology and new, future arrays.

If the REMUS 100 has been the sedan of the UUV community, the larger 600 is its pick-up truck.

"On these bigger vehicles, there are sensors in development with the Office of Naval Research that could fit on the [REMUS 600] but could not fit on the smaller vehicles," said Todd Webber, a SPAWAR Systems Center representative working with Navy EOD.

"Some of those new, advanced sensors are going to give us better resolution, and also do sensor penetration of buried targets that we currently don't have a way to get to - other than the marine mammals," said Webber.

UUVs are in use at Marine Corps Base Hawaii during RIMPAC because the warm, clear waters off Hawaii provide the perfect combination to test and document how far the 600 can go to replace diver and mammal missions.

"We're getting some good video documentation by putting the UUV in an autonomous mode between set points," said Mineman 1st Class (EXW/SW) Lindsey Wohlgemuth, of EOD-1. "We're also doing what we call a 'loiter mode', where the 600 goes in a circle. We can actually get good, visual documentation of the vehicle here."

The UUV looks like a mini-submarine. Its body is just over 10 feet long and glides with silent precision through the water, all the while using advanced SONAR to map the ocean floor and look for anomalies in the surrounding waters.

During RIMPAC, divers lay training mines to test the UUVs ability to locate the devices. EOD technicians pour over the sensor data that comes back both in raw data and visual recordings in trailers at a forward operating base.

From here, the crews have access to the many training areas on Oahu's windward side taking their 11-meter Rigid Hull Inflatable Boats (RHIBs) either into the bay to perform shallow water operations, or out into the ocean for deep-water testing.

EOD technicians drop the REMUS 600 from the side of the RHIB, set it on its way then control and monitor the silent vehicle as it submerges to collect its valuable data. The EOD techs can control the vehicle from the RHIB and get real-time updates while the UUV is submerged.

If in hostile waters, the upgraded REMUS 600 provides EOD techs the ability to get their missions done faster and better.

"The REMUS 600 has more capability than the 100 does, and we've been using the 100s for a while," said Wohlgemuth. "It's a faster vehicle and has a larger sonar range, so we can go in and do a mission faster than the 100s can."

While SPAWAR and the Navy are looking to greatly decrease the number of missions they use dolphins and sea lions for, it may be some time before the mine countermeasure community can completely remove them from service.

"Dolphins have had their sonar capability evolve over millions of years," said Webber, "and we've only been at it for less than 100 [years]. There are things they can do that we're not even close to yet with unmanned vehicles, but by using UUVs we can at least keep our human divers and their [marine] mammal counterparts out of some dangerous situations."