Navy underwater devices go on test missions in Narragansett Bay
Boaters in Narragansett Bay often contemplate what kind of marine life might be swimming right below them in the water. They may be surprised to learn that not every denizen of the bay is a living, breathing entity. For a number of years the bay’s fish population has been joined by strange creatures called UUVs.
The unmanned underwater vehicles are part of a program being run under the direction of the Naval Undersea Warfare Center in Newport. The ultimate goal is to produce a fleet of the self-driven vehicles that will be put to use for things like mine detection, ocean floor mapping, and eventually intelligence gathering and antisubmarine warfare.
According to Dan French, who has been at the warfare center for 27 years and the head of the autonomous undersea vehicles division for the last nine, the thought of undersea vehicles doing missions is nothing new. The Navy has been testing UUV systems since the 1970s, but in the last seven or eight years the focus has been on advanced autonomous behavior and advanced navigation methods.
“Over the last few years,” said French, “we’ve been testing some algorithms that we’ve either developed ourselves or helped to develop to do those types of behaviors with the vehicles. We’ve been testing those at sea.”
According to French, the underwater vehicles have circumnavigated Conanicut Island as part of their missions on several occasions. He said that while it doesn’t happen on a regular basis, there have been times when the testing took the vehicles beyond Block Island, and they returned via the West Passage, rounded the northern tip of Conanicut Island, and headed home to Newport.
Although the vehicles will eventually be launched from submarines, during the testing phase they are deployed from surface ships that also retrieve them at the end of the mission. The most common unmanned underwater vehicle, known as MARV, is cylindrical in shape. It is 12 3/4 inches in diameter, and ranges from 11 to 15 long. It can weigh anywhere from 500 to 700 pounds.
The biggest obstacle in the development process so far has been energy. There is not yet a battery in existence that will allow the vehicles to undertake the kind of extended mission of up to 70 days that the Navy is hoping to be able to accomplish within five years.
“Energy is a significant technical challenge for UUVs,” French said. “We’re looking for substantial endurance in the water and we’re limited with the batteries that we use typically now.”
French said that if the type of energy source that is required for extended missions was available today, the vehicles could support such missions. But he added that there are other factors at play as well.
“Reliability and robustness is a challenge. We would have to step things up in terms of our vehicle reliability for a long run of that magnitude.”
While military research is leading the way, industry is following suit with UUV development of its own. Nonmilitary uses for the technology already include the inspection of oil rigs in the Gulf of Mexico. There are also UUV ap- plications for measuring oceanographic data and recording it to a database.
French said that from his perspective, the objective is to support naval missions with the vehicles and to have them be more integral to the fleet than they are right now. At present there are not a large number of the systems in development or actually in the Navy.
“We would like to see that change,” he said, “and to have these things be a little bit more indigenous to the fleet.”
Newport is not the only place where the military is researching these systems. Other warfare centers and naval facilities are also doing UUV-related research, and having demonstrations of their own.
One problem that the UUV team has encountered on previous missions involves over-eager boaters who spot the vehicles in the water and think it might be a good idea to grab a souvenir of their time on the bay. To help discourage this kind of activity, the Navy uses a charted range and puts out a notice to mariners about their operations and intentions. There are also chase boats that keep the range clear and head off interested boaters.
“We’ve had people look at them and follow them,” French said. “A few other strange occurrences have happened. It’s a curiosity I’m sure.”
In addition to MARV, French’s team is working on a lighter, more portable vehicle called Razor. Razor is an ellipsoidal-shaped device weighing less than 200 pounds. It is being developed based on interest from the Department of Homeland Security, which hopes to use it to intercept divers. It is still in the research and development stage, and not yet in production.
“We pursued nontraditionalshaped vehicles in the past,” French said. “We’ve built big vehicles with wings, and smaller vehicles. Some are wider and flatter in shape. NUWC has put a lot of effort into different hydrodynamic designs and that adds to energy efficiency. You don’t want a high drag shape in the water. It’s something we’ve been researching for years.”