The Improved SSN-688 Design

Of all the nuclear submarines designed by the United States, none has been the subject of more political infighting and controversy than the Los Angeles (SSN-688) class. The design has its roots in a series of incidents that occurred in the late 1960s, right at the time the United States was trying to decide just what kind of nuclear attack submarine (SSN) to build to replace the highly successful Sturgeon-class boats. The infighting began with the desire of then-Director of Naval Reactors (DNR) Vice Admiral Hyman G. Rickover to build a high-speed (over 35 knots)[9] submarine capable of directly supporting the fleet of aircraft carriers that represented the backbone of American seapower.

The U.S. Navy organization charged with actually developing the specifications and design for the next generation of SSN, the Naval Sea Systems Command (Navsea), favored a design called Conform that would not be as fast as Rickover's design, but would have the advantage in areas such as habitability and quieting.

In the end, the decisive event that swung the situation in Rickover's favor was something known today as the Enterprise incident, which was a shock to the U.S. Navy and intelligence communities. In early 1969 the carrier USS Enterprise (CVN-65) and her escorts left their base in California for a war cruise to Vietnam. As she left harbor, U.S. national intelligence picked up message traffic indicating that the Soviet Union was going to dispatch a November-class SSN to intercept the carrier and her group. In an attempt to establish once and for all just how capable the first-generation Soviet SSNs were, the top battle group was provided with air cover from ASW aircraft and then told to outrun the November. It did not quite work out though, as the presumably slower Russian boat was able to match speed with the Enterprise. At 30 knots the game was called off. When word reached Washington, D.C., it caused rapid reassessment of just how capable the Russian SSNs really were.

Up until that point, it was assumed that the Novembers were only capable of speeds like those of the Nautilus and the Skates, around 20 knots. Yet here was one doing 50 percent better than that and not even trying! And what did this mean about the newer generation boats, such as the Victor I and II classes? In addition, there were mounting indications that the Soviets were working on a new class of deep-diving (over 2,000 feet/700 meters), extremely high speed (over 40 knots) SSNs.

In fact, the performance of the Novembers was due to the extreme lack of radiation shielding. Much like a hot rod that has been stripped of everything that weighs it down, the Russian boat simply did not have to haul around the reactor shielding that every other civilized nation considered essential to the good health and safety of their sailors. The November's superiority was based on a misinterpretation of the information, but there was no way to know that at the time. And Rickover was not a man to let slip an opportunity that would help justify his point of view. Through his network of Navy and congressional supporters, he pressured the Navy to kill Conform and build a class of his high-speed fleet boats. In the end he won authorization for a twelve-boat class of his fleet submarines, though to help gain critical budget authorization votes in Congress, he broke with the longstanding Navy tradition of naming submarines after sea creatures and instead named them for the home cities of the twelve congressmen who swung their votes in his favor. (Rickover is alleged to have said, 'Fish don't vote!')

The first boat of the class, the Los Angeles (SSN-688), was to be the embodiment of his ideas of speed and power, but from the very start, it was a series of compromises. It is said that a camel is a horse designed by a committee, and the Los Angeles was no exception to that rule. The first problem had to do with fitting the massive S6G power plant into a hull with the dimensions needed to achieve the 35-knot speeds specified by Rickover. Quite simply, the reactor was going to come in 600 to 800 tons overweight. This meant that one or more of the key specifications of the boat-torpedo tubes/weapons load, habitability, radiated noise level, speed, sensors, or diving depth-was going to have to be reduced. The compromise was to thin the hull and limit the diving depth of the new boats to about three-fourths that of the Sturgeons and Permits (950 feet/300 meters). In addition there would be some severe compromises in habitability, forcing even more of the crew to hot bunk. As it was, there was very little reserve buoyancy (around 11 percent) and less growth potential than in any other SSN ever designed by the United States.

Once the design of the Los Angeles was finalized, there was the matter of selecting a prime contractor. The Navy chose the Electric Boat Division of General Dynamics Corp., despite their having submitted a bid that, in retrospect, was not capable of recouping even the costs of building the first group of twelve boats. Clearly, Electric Boat was 'betting on the come'-that they could recover their lost profits from construction of boats beyond the first twelve units. Unfortunately, they did this at a time of relatively high inflation and recession in the economy, and the terms of the contract began to make it impossible for Electric Boat to break even on the first boats. Then a Navy inspection of welds found that a number of the boats had either faulty or missing welds on critical parts of the pressure hulls. This meant a number of the boats had to be completely rebuilt, further increasing costs to Electric Boat. In the end the U.S. Navy had to bail out Electric Boat and pay the costs of the overruns on the Flight I boats. This bailout caused a massive scandal that wound up costing General Dynamics the sole-source contract for the subs as well as causing the indictment of the Electric Boat yard manager on bribery charges. The Navy got the boats, but at a massive cost to the taxpayers.

On the positive side, what the Navy and taxpayers did get were the fastest, quietest, most capable SSNs ever built. On trials, the new boats proved to be all that had been hoped for them. And in 1976, when the Los Angeles was commissioned and sent on patrol, she clearly marked the beginning of a new era of attack boats. Part of this came from the improved sensor suite. For the first time, an integrated sonar suite was included in the design of the boat from the very start. In addition, she was among the first boats to be able to take advantage of the new family of submarine weapons, the Mk 48 torpedo and the UGM-84 Harpoon antiship missile, that were coming on line at that time. Thus what the United States got with the Flight I Los Angeles- class boats was an extremely capable camel.

USS Miami (SSN-755) JACK RYAN ENTERPRISES, LTD. USS Miami, external layout. JACK RYAN ENTERPRISES, LTD. Logo of USS Miami. JACK RYAN ENTERPRISES, LTD.

This might have been the end of the Los Angeles story except for the sudden chill in the Cold War that occurred in the late 1970s. After the downturn in East-West relations, the Navy got an authorization for additional units of the Los Angeles class. And when Ronald Reagan won the presidency in 1980, the construction of additional submarines as part of the '600-ship Navy' clearly meant more Los Angeles-class boats. In these boats were to go some of the improvements that had been planned for the class early on. Starting with the USS Providence (SSN-719), the type designation changed to Flight II. The Flight II boats had a number of improvements, particularly in the area of weapons stowage. One of the problems with U.S. SSNs had been the limited number of weapons (around twenty-four) that could be carried in their torpedo rooms. And with the addition of Harpoon and the new family of UGM-109 Tomahawk cruise missiles (antiship and land attack versions), it was getting tougher to plan an appropriate weapons load. To get around this, a twelve-tube vertical launch system (VLS) for Tomahawk cruise missiles was added to the forward part of the boat, where room had been left for them in the original design.

Almost two dozen of the Flight II boats were built, and their cruise missile firepower proved quite useful during Operation Desert Storm in 1991. The Flight IIs were also the first major group equipped with the new anechoic/decoupling coating designed to reduce the effectiveness of active sonars, as well as to reduce the noise radiated by the boat. Eventually all of the Los Angeles-class boats would be retrofitted with this coating. Another major improvement was that beginning with the Flight II boats, the S6G reactors were fitted with a new high- output reactor core. This allowed the Flight II boats to maintain their high speed (over 35 knots) despite the additional drag imposted by the new coating.

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