At approximately 1000 meters under the surface of the ocean lies a channel of 'water density' called the 'SOFAR' channel. It is a density of water that allows the transmission of sound globally at the same depth. The Navy is aware of this water layer as during WWII they used "Sofar Bombs" to deploy distress messages to other vessels in order to be rescued.
SOFAR (click here) - Acoustic pulses travel great distances in the ocean because they are trapped in an acoustic "wave guide". This means that as acoustic pulses approach the surface they are turned back towards the bottom, and as they approach the ocean bottom they are turned back towards the surface. The ocean conducts sound very efficiently, particularly sound at low frequencies, i.e., less than a few hundred Hz.
The novel The Hunt for Red October describes the use of the SOFAR channel in submarine detection.
In the case of whales, it isn't about 'distance' it's about 'frequency' and allowing the Navy a frequency that won't hurt or destroy the marine mammals that are already endangered. There is no such 'thing' as a safe distance to marine mammals, there is only operating sonar outside the frequency that damages them. When will the Navy get out of it's own way and develop sonar that protects and defends endangered marine mammals as well as the nation.
IT'S NOT ROCKET SCIENCE !!!!
Federal court rejects Bush stance over Navy sonar use
5 days ago
LOS ANGELES (AFP) — A federal court has ruled against President George W. Bush's bid to exempt the Navy from environmental laws when it uses sonar equipment considered potentially harmful to whales and other marine life, according to court documents.
The three-judge panel in the federal appeals court upheld a lower court decision requiring the Navy to take safety precautions to reduce possible harm to whales and other marine mammals when it employs sonar for training exercises off the coast of California.
The court, which handed down its ruling late on Friday, gave the Navy 30 days to appeal the case to the Supreme Court.
Environmental groups that took the Bush administration to court over the matter welcomed the ruling as an important precedent.
"The court is saying that neither the President nor the US Navy is above the law," said Joel Reynolds, director of the Marine Mammal Protection Project at the Natural Resources Defense Council (NRDC).
http://afp.google.com/article/ALeqM5goz_Z25ZPQRrtMIiy8YP0RX5FGsg
Navy Sonar Restricted Off Hawaii Coast
By SUDHIN THANAWALA – 6 days ago
HONOLULU (AP) — A federal judge has ordered the Navy to take additional precautions when conducting sonar exercises off Hawaii that environmentalists say can seriously injure or kill marine mammals.
U.S. District Judge David Ezra said Friday the Navy cannot conduct exercises within 12 nautical miles, or 13.8 miles, of the shoreline, where species that are particularly sensitive to sonar, such as the beaked whale, are found.
Among other requirements, the Navy must look for marine mammals for one hour each day before using sonar, employ three lookouts exclusively to spot the animals during sonar use and stop sonar transmission altogether when one of the mammals is within 500 feet.
It must also gradually increase its sonar power before beginning any exercise to allow animals to leave the area before they can be harmed.
The Navy faces a similar order in California, where a U.S. District Court judge in January issued an injunction that created a 12 nautical-mile no-sonar zone off Southern California.
http://ap.google.com/article/ALeqM5jLbXdcs-qiXUTGC3kWW8Atb7v_mwD8V4FE9O0
Navy Sonar Ban in Southern Calif. Upheld
By ROBERT JABLON – 5 days ago
LOS ANGELES (AP) — The Navy must abide by limits on its sonar training off the Southern California because the exercises could harm dozens of species of whales and dolphins, a federal appeals court ruled.
The 9th U.S. Circuit Court of Appeals on Friday night rejected the Navy's appeal of restrictions that banned high-powered sonar within 12 nautical miles of the coast and set other limits that could affect Navy training exercises to begin this month.
Also on Friday, a federal judge in Hawaii issued a similar ban for that state's coastline.
In the California case, the appellate judges let stand most of a lower court injunction that set the limits, but altered two restrictions that the Navy argued could harm the readiness of its ships for combat.
Conservation groups that had sued to block the Navy's use of high-powered sonar said the decision was a victory for their side.
"The court is saying that neither the president nor the U.S. Navy is above the law," Joel Reynolds, director of the Marine Mammal Protection Project at the Natural Resources Defense Council, said in a statement Saturday.
http://ap.google.com/article/ALeqM5jLbXdcs-qiXUTGC3kWW8Atb7v_mwD8V55AO00
Navy makes case for Atlantic sonar training
07:09 AM EST on Wednesday, March 5, 2008
Associated Press & 13News
VIRGINIA BEACH (AP) -- The Navy tonight will hold the first of several public hearings on the environmental impact of its Atlantic Fleet sonar training.
Click to watch video
The use of sonar has became a concern to many environmentalists, who worry about its effect on whales and other marine mammals.
The hearing comes days after the discovery of three dolphins on the shores of the Back Bay National Wildlife Refuge.
To weak to be saved, they were euthanized.
A U.S. Fleet Forces Command spokesman said the Navy hasn't conducted sonar tests within 200 nautical miles of the Virginia coast for more than a week.
http://www.wvec.com/news/military/stories/wvec_local_030408_navy_sonar_hearing_.1f36aeb3.html
