Tuesday, February 24, 2015

Soviet Delta-class submarine threat!

When the Soviet Delta-class submarine entered stage right in December 1972, the U.S. Navy shuddered. With a quiver of twelve R-29 ballistic missiles, each capable of delivering megatons of destruction from almost 5,000 miles away, the Delta made U.S. ASW techniques all but obsolete. Prior to the Delta’s arrival, Soviet ‘boomers’ with shorter-range missiles, in order to get close enough to the United States to launch, needed to transit from Murmansk, curve around Norway, and drop down through the Greenland/Iceland/U.K. gap. A swarm of American ships and planes greeted them there, as well as several fast-attack boats ready to latch on like trained bulldogs. With the advent of the Delta class, the Soviets could employ a new strategy: slip under the Arctic ice north of Murmansk and hide for months on end. When and if the order came to fire, they could sneak from under the ice cap, come shallow, and launch. By the time a U.S. submarine found them, it would be too late.

The Delta class rivaled America’s Benjamin Franklin’class boomers in every way. In fact, the United States had actually fallen behind in this area, having not launched a new ballistic missile submarine since the USS Will Rogers (SSBN-659) hit the water in April 1967. Fortunately, U.S. attack submarines were a bit more advanced, but these capable work horses were ill equipped to find Delta submarines hiding under an Arctic ice floe, and no acoustic or signals intelligence yet existed on the Soviet’s new boat. Without that intelligence, finding a Delta in open waters posed a problem.

The issue of locating these ‘ice boats’ consumed the navy and the NSA, but they were not completely caught by surprise. Anticipating such an advancement from the Soviets, the navy had launched a new ASW program in 1964 that gave the Classic Bulls Eye program some stiff competition for funding. Under the direction of Vice Admiral Charles B. Martell, the Long Range Acoustic Propagation Project (LRAPP) sought to bring heretofore scattered ASW technologies and efforts, including SOSUS, under a single roof. Employing only a few scientists and requiring modest funds in comparison to other programs, LRAPP conducted scientific experiments and exercises that teamed top ASW civilian minds with navy counterparts. Unfortunately, all of the initial experiments failed. The brass threatened to cancel LRAPP until Dr. Marvin Lasky at the Office of Naval Research saved the day.

Lasky helped deploy a miles-long string of acoustic hydrophones towed by a ship or submarine. He called this invention the Interim Towed Array Surveillance System (ITASS), which was, essentially, a movable SOSUS sonar array. The experiments with ITASS that followed proved critical in finding a way to detect Soviet submarines in northern waters near Murmansk. During the height of the program, two opposing scientific camps stood their ground. The LRAPP scientists believed that sound in the ocean traveled in a straight line, or directionally. This meant that sound characteristics would differ depending on where they originated, and submarines could be detected from very far away. Others, including a team of AT&T scientists, argued that noise didn’t travel in straight lines, and subs could only be heard if they were not too distant.

Current SOSUS arrays in the Atlantic could not detect Deltas in the Arctic. The navy wanted to extend SOSUS into the North Atlantic to fix this problem. AT&T scientists, convinced that their ‘omnidirectional’ sound viewpoint was correct, insisted that this move would be a waste of money. SOSUS arrays wouldn’t be close enough to the Arctic to do the job. The LRAPP engineers thought otherwise and challenged AT&T to a duel, with the stakes being the demise of the $180 million SOSUS expansion. If the AT&T scientists were right, the project was doomed. If the LRAPP scientists were correct, SOSUS lived. Moreover, future ASW capabilities could be dramatically improved, tipping the scale back in America’s direction.

After a two-week experiment in which ships towed the new ITASS arrays, the LRAPP team took home the gold. They proved that sound propagated directionally. This led to the permanent installation of SOSUS in the North Atlantic and the development of ITASS arrays that could be towed by attack submarines. Soviet vessels could now be detected from far greater distances than ever before. The navy also ordered operational and procedural changes in the world of antisubmarine warfare and increased funding for ICEX Arctic experiments conducted on a tiny ice floe north of Alaska.

Sonar, weapons, and other systems on submarines operate differently in Arctic conditions versus open ocean areas. To better understand these dynamics, every two years, the navy sent two fast-attack submarines to a moving ice floe in the Arctic, a few hundred miles north of Prudhoe Bay, Alaska. Over a two-week span in the warmer month of March, a team of more than sixty naval personnel, along with civilians from the Arctic Submarine Laboratory and Applied Physics Laboratory, teamed with support personnel and a few cooks to build a temporary base camp for Operation ICEX. Two attack boats spent two weeks conducting experiments on new sonar and communications systems designed for Arctic conditions and firing practice torpedoes at each other. Scientists monitored results and used these findings to improve system and weapon designs for Arctic use.

These improved designs found their way into a new class of U.S submarines originally launched on March 3, 1967.

These Sturgeon-class attack subs boasted vast improvements in quieting technology, coupled with the latest espionage gear. The Soviets had nothing in their attack submarine deck that compared. By 1973, after the success of the LRAPP experiments, the navy expanded SOSUS to twenty-two installations in the Atlantic and Pacific.

American engineers leveraged ITASS and HFDF technologies to design towed sonar arrays and miniaturized versions of Boresight/Bulls Eye detection and DF technologies that could be installed on U.S. ships under the Classic Outboard program. These smaller HFDF systems also found their way onto Permit (formerly Thresher) and Sturgeon-class submarines as integral parts of BRD-6 and-7 ESM systems. Now when Ivan transmitted a burst signal, lit off a radar, turned a screw, or farted into the wind, an American T-Brancher or sonar tech could catch the scent.

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