USS HARRY S. TRUMAN At Sea (NNS) -- Sailors from Harry S. Truman Carrier Strike Group (HST CSG) used active sonar to hunt submarines during the strike group's composite training unit exercise (COMPTUEX) June 9-July 3.
COMPTUEX is an intermediate-level exercise required of each carrier strike group before it deploys. The exercise brings ships and aircraft together to prepare to project force as a strike group in the interest of global maritime security and to protect the nation's homeland security.
Although sonar operators receive various types of synthetic antisubmarine warfare (ASW) training, nothing compares to using active sonar at-sea to hunt actual submarines.
"The ability to run silently on battery power makes modern diesel submarines a significant threat against U.S. forces patrolling the oceans. An undetected submarine can quickly cripple a high value target such as an aircraft carrier before the ships accompanying it can effectively respond," said Capt. Robert C. Barwis, commander, Destroyer Squadron (DESRON) 26,
According to Lt. Christopher W. Clevenger, DESRON 26 submarine operations officer, detecting these threats is the duty of all Sailors within the ASW community, requiring simultaneous training at-sea by ships, submarines, planes and helicopters. Through the use of helicopters and towed sonar arrays, ASW teams can detect most sub-surface threats, but the only way to detect an ultra-quiet threat before it comes within striking range is with of active sonar.
"ASW training, including the use of active sonar in at-sea training scenarios during COMPTUEX, is vital to training sonar operators and ensuring the Navy stays competent in its ability to combat sub-surface threats," Clevenger said.
Because ASW skills are perishable and deteriorate rapidly, repeated training is required.
"The proficiency goes away if you don't maintain and keep up with it," said Sonar Technician (Surface) 2nd Class Alex Szlamas, a sonar operator with DESRON 26's ASW team. "That goes for the ability of an operator working on a destroyer platform to evaluate accurate types of contacts on their sensors, all the way to the command and control staffs, like the DESRON."
Sailors have opportunities to hone their ASW skills during COMPTUEX.
"There are a lot of elements that make background noise when using sonar - whales, background shipping freighters, even shrimp. All these create a situation that can easily mask a diesel submarine, which can sound like a shipping freighter," said Clevenger. "It's very hard to mimic all those sounds in a simulation, which is why we need real-time training in a real environment.
"Unfortunately these diesel submarines don't have a lot of tonal frequencies that we can pick up when they're running on battery. They can be very difficult to locate if we're just using passive sonar until, unfortunately, they get too close. Worse, they become even harder to locate in littoral waters where background noise is both higher and more diverse, providing a larger protective sound shield for the subs."
Although some concern has been raised lately over the adverse effect of active sonar and marine wildlife, the Navy is one of the leading sponsors of marine mammal research, spending $26 million in fiscal year 2008, including efforts to understand the relationship between sound and marine mammals.
"We follow a lot of precautions to ensure the safety of marine mammals," said Clevenger. "One of the common practices we use is to have sonar operators trained specifically to identify and locate marine mammals and we'll limit, or cut off, the power of our active sonar as they get within a certain range."
With more countries fielding more submarines, it is very important for strike groups to continue to practice ASW so they are better prepared for sub-surface threats and able to maintain safe and effective fleet operations. The Navy recently completed a comprehensive Environmental Impact Statement for Atlantic Fleet Active Sonar Training (AFAST), which evaluated the environmental effects of the Navy's training activities on all of its training areas. As a result of this study, the Navy will continue with the present level of training along the East Coast of the United States and within the Gulf of Mexico as authorized by federal regulators. As part of this authorization, Navy continues to implement protective measures set forth by the National Marine Fisheries Service.
Carrier Strike Group 10 (CSG-10) is made up of the aircraft carrier USS Harry S. Truman (CVN 75), with its embarked air wing, Carrier Air Wing Three (CVW-3) and embarked Destroyer Squadron 26 (CDS-26), guided missile cruiser USS Hue City (CG 66); guided-missile destroyers USS Carney (DDG 64), USS Oscar Austin (DDG 79) and USS Winston S. Churchill (DDG 81); attack submarine USS Norfolk (SSN 714); and independently participating frigates USS Stephen S. Groves (FFG 29) and USS McInerney (FFG 8).
CVW-3 consists of Strike Fighter Squadrons (VFA) 32, 37 and 105; Marine Fighter Attack Squadron 312; Electronic Attack Squadron 130; Airborne Early Warning Squadron 126; Carrier Logistics Support Squadron 40; and Helicopter Anti-Submarine Squadron 7.
For more news from USS Harry S. Truman (CVN 75), visit www.navy.mil/local/cvn75/.