IN THE MILITARY
GREGG K. KAKESAKO / GKAKESAKO@STARBULLETIN.COM
Petty Officer Trang Snell uses long-range binoculars while standing watch on the bridge of the Pearl Harbor-based destroyer USS Chung Hoon.
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Navy attuned to whale songs
RIMPAC ships will avoid sea mammals by listening for their acoustic signature
With 14 years of experience, Petty Officer Charles Paul is confident that he can quickly recognize the sounds made by whales and other marine mammals and avoid any unnecessary sonar contact.
"There are certain characteristics that biologics send out," said Paul, 33, a sonar technician aboard the Pearl Harbor-based destroyer USS Chung Hoon. "There are certain high pitch frequencies and certain rhythms that marine mammals are known for.
"We usually hear the noise first and depending on the conditions of the sea sometimes we can get a good broadband display."
For the first time in the 35-year history of the Rim of the Pacific naval war games, all of the 35 U.S. and allied ships in the exercise will be required to reduce the level of the power of their sonar by 6 decibels if a marine mammal is within 3,300 feet, and a 10 decibel reduction within 1,650 feet. All sonar operations are stopped if the marine mammal is within 660 feet.
There also are geographical restrictions under the first permit ever issued by the National Oceanic and Atmospheric Administration to protect marine mammals from possible sonar damage.
Active sonar cannot be used for this RIMPAC exercise within 14 miles of where the seabed is 660 feet deep or less.
Unless the 509-foot destroyer Chung Hoon is on tactical alert and actively seeking sonar targets, it would only be Paul and another technician who would be sitting before their consoles -- their faces painted in an eerie green glow as they listen to noises in the ocean around them.
The Chung Hoon is equipped with a towed array sonar with microphones that are dragged a mile behind the destroyer. Sonar technicians also periodically measure the temperature, pressure and salinity of the water with a deep water probe, since these factors affect how far an object can be detected.
Paul said his job would be to immediately notify his supervisors that he had "a sonar bearing." The two technicians would then evaluate what "they see on the screen."
That information also is relayed to Chung Hoon's combat information center, located a deck above the destroyer's sonar operations, and to Lt. Tim Fox, the ship's weapons and tactical action officer, to determine if it already has been identified.
One of the tools Fox would use in identifying the sonar contact would be Petty Officer Trang Snell, whose duties include standing watch on the bridge of the Chung Hoon, making sure there are no obstructions in the way of the destroyer.
Using the bridge's high-powered binoculars, Snell, 33, said she is able to identify a whale as far away as 10 miles.
"As soon as I see something like the spray from a whale," Snell said," I report it to the officer of the deck."
Cmdr. Dave Welch, skipper of the two-year-old destroyer, said such sightings are routinely reported to him. It is only on his orders that active sonar can be turned on the Chung Hoon.
Unlike passive sonar operations, active sonar sends out pings that help the ship's technicians determine the location and distance from the object they bounce off.
Welch said his destroyer "always takes any action to avoid them (marine mammals)."
The Navy acknowledges that the geographical restrictions will have an impact on RIMPAC, since one of its key objectives is training Pacific Fleet warships to operate in shallow, offshore waters where diesel submarines now operate.
Cmdr. Bruce Shaw, Pacific Fleet's anti-submarine warfare director, said there are more than 140 diesel submarines operated by Asian nations, like North Korea.
"Diesel submarines, which is the coming trend," Shaw said, "are even more difficult to find because they are very, very quiet. Once a diesel submerges, he's got batteries that are powering him. Batteries don't make a lot of noise. We can't hear him, but they are vulnerable because they have to come to surface periodically to recharge their batteries."
Shaw said these diesel submarines operate close to shore and in vital shipping lane "choke points" like the Strait of Malacca. "These are areas where commercial shipping need to go," Shaw said, "areas where we as a Navy need to go to support other missions."
Capt. Matt Brown, Pacific Fleet spokesman, said shutting down the Strait of Malacca would have worldwide economic impact.
"Japan, Korea, China get most of their oil from the Middle East through the Strait of Malacca and the South China Sea. ... Even the thought that those straits could be shut down would result in a crumbling effect."
There are no diesel submarines in the U.S. fleet. All of them are nuclear powered. Three diesel subs from Japan, South Korea and Australia will join Pacific Fleet's nuclear subs USS Los Angeles, USS Chicago and USS Key West for RIMPAC.
Brown added "the importance of anti-submarine is learning to operate in environments where these subs are located."