Just as project NOBSKA in 1956 "steered" the U.S. Navy to a new generation of smaller solid-propellant POLARIS-type FBMs, so too STRAT-X/ULMS-I steered" the Navy to the next generation SSBN/FBM system. SECDEF Robert McNamara, on 1 November 1966, initiated a comprehensive study on U.S. ballistic missile performance characteristics required to counter potential Soviet strategic offensive forces and anti-ballistic missile proliferation in the time frame 1975 to 1985 - 90.
The study was conducted under the auspices of the Research and Engineering Support Division of IDA. The study was known as STRAT-X (for Strategic eXperimental). Based on a previous study done by the IDA earlier that year called PEN-X (for "penetration of enemy missiles, experimental"), the deliberately-nebulous title was concocted to prevent bias in the study toward any land-, sea-, or air-based system. Posting the likelihood that the Russians would deploy, in the future, extremely-powerful and highly-accurate ICBMs as well as an effective anti-ballistic missile system, McNamara's study requested appropriate countermeasures. The STRAT-X study was headed by General Maxwell Taylor, President of IDA. The "working" study group was headed by Fred Payne of IDA.
The "working" panel included executives from several major defense contractors and independent corporations. The Advisory Committee were mostly military men. RADM George H. Miller (OPNAV) and RADM Levering Smith, (SP-00)the Navy contingent on the STRAT-X panel, "representing both the [Naval Operations] staff and the 'hardware' side of the Navy"- participated, but Naval Reactors Branch, which furnished the nuclear power plans for all nuclear-powered Navy vessels, did not.
Candidate STRAT-X system concepts were evaluated for: (Primary) the ability to retaliate against a Soviet urban-industrial target and (Secondary) flexibility to perform selected counterforce and controlled-response missions.
STRAT-X investigated and reviewed over 125 different missile-basing systems for the purpose of finding the most efficient and survivable option, the only prerequisite being that the candidate system had to be unique in comparison with previous or existing platforms. Going into the study, the Air Force had lobbied for a replacement for the Minuteman ICBM, and it appeared initially as though the Air Force missile might be chosen, but the requirement for new ideas also worked in the Navy's favor.
Other than submitting an improved POSEIDON, the Navy STRAT-X study teams under Dr. Willie Fiedler of Lockheed proposed a different submarine concept called ULMS. After examining these and other alternatives that ranged from the sublime to the ridiculous (such as missile-firing submersibles, ICBMs carried on trucks, surface ships or barges, new bombers, seabed platforms (perhaps located in Hudson Bay)), the STRAT-X panel concluded in 1968 that the Navy's ULMS represented the least costly and most survivable alternative. Miller claimed the panel envisioned a "rather austere" ship with little speed and, consequently, a small nuclear power plant. The Navy supported the view that ULMS was to incorporate very-long-range missiles into submarines of rather conservative design, based on existing submarine technology. The proposed submarine would not necessarily be deep-diving.
The STRAT-X study proposed a slow, quiet, austere new submarine that did not necessarily have deep diving capabilities. Its slow speed and quiet signature would reinforce its strong survivability characteristics and lower the probability that it would be detected. Stealth was a higher priority than speed, and the study concluded that its top speed should be no higher than 13 knots. Additionally, the study members suggested that the new missile carried by the platform would have a range of around 6,000 nautical miles (nm) and that each boat would have no fewer than 16 missile tubes.
The submarine would have a central watch station that would require a smaller crew, thereby placing fewer demands on life support systems than those on previous submarines. Finally, it would employ new modular construction to build the hull and interior systems in sections, which would increase construction efficiency and hopefully shorten the production schedule.
Upon completion of the DoD's STRAT-X Study, the Navy (SPO) continued its own studies of advanced undersea system concepts. Lockheed, General Electric, MIT, Sperry, and Westinghouse were all involved. Electric Boat was funded by Navships for interfacing submarine studies.
Subsequent to STRAT-X, the ULMS effort was continued by SSP at DDRE direction. The cost of concurrently developing a new submarine and missile was judged to be inconsistent with DoD funding and dedication. Since the submarine is the long lead item (seven years from funding to IOC), minimum subsystem changes were dictated for the new submarine.
Submarine design work subsequent to STRAT-X was directed along the encapsulated missile concept as opposed to the FBM concept of bare vertical launch from a fixed mount tube. RADM Levering Smith, PM-1, stated that the encapsulated missile would be retained only if real merit could be established. Electric Boat was requested by CAPT Gooding (SP-20) to do a submarine feasibility study for both bare vertical and encapsulated stowage and launch of the LRC3 missile. Missile length and first stage diameter are dependent variables. Each concept was allowed to consider dimensions best suited to the stowage mode. The trend for vertical stowage was to make the missile short, and the trend for horizontal encapsulated stowage was to make it long until it hurts. The tradeoffs between launch mode concepts were conducted during CY 1968.
In January 1969, the contractors involved in the stowage mode studies presented their data -- while the ship people favored bare vertical, the missile people favored, and SSPO would recommend the traditional FBM bare vertical launch and stowage used on previous Polaris submarines.
Both Electric Boat (Groton, Connecticut) and San Francisco Bay Naval Shipyard (Mare Island (Vallejo), California) were requested to provide ULMS SSBN concepts. By December 1969, the ULMS team at Mare Island had developed three basic hull forms, concentrating their efforts on developing an external launch tube hull.
Two of the Mare Island designs, the "FISHBONE" and "D Frame" concepts, involved advanced pressure hull construction techniques. The FISHBONE concept, in the missile section, is configured to present a non-circular pressure hull. It was conceived to use the inboard half of the missile tube as the primary pressure hull in the missile tube section of the boat. The "D Frame" achieved a similar non-circular missile tube section by using a flat plate technique outboard of the missile tube as one portion of the hydrostatic hull.
The third concept, "TWIN TUBE", was Mare Island's preferred configuration. In this hull form, the missile tubes (located in the water) have port and starboard access tubes running fore and aft that provide access to the fore and aft part of the boat, as well as access to the missile tubes.
Four FBM hull configurations were offered by Electric Boat, one "external" (wet) tube design and three "internal" tube design: single hull, double hull, and oval hull. The three tube abreast oval hull design had a variant configuration, two tube abreast.
There were also studies made of tilting the launch tubes athwartship and/or fore/aft attitude. The athwartship angle was limited to something less than +10 deg from the vertical. The fore and aft angle could be varied quite a bit more (e.g. +90 deg possible but not practical). A 50 deg fore/aft tilt was studied. However there was a general disbelief in any merits of loading and launching on any line that was not in line with gravity (e.g., vertical).
These studies were evaluated and Lockheed issued a report on 9 January 1970. It stated that the FBM Weapon System has always accepted the classic, POLARIS-POSEIDON 2 x 8 columnar, vertically-tubed, missile zero pointing center, battery arrangement. The data indicated no significant advantages, insurmountable problems or even significant sensitivity to various arrangements. This points to the practical position of "why change," when we might, with some assurance, find the unk-unks [unknown unknowns] hidden within some other arrangement. It is these unk-unks that can react with negative synergism to create significant problems.
The report concluded then that the classic FBM battery arrangement should be maintained. Vice Admiral Hyman Rickover, head of the Navy’s Nuclear Propulsion Directorate, argued that the new submarine needed to reach a speed of at least 24 knots to keep up with Soviet submarines. Although Soviet submarines at this time could reach speeds of up to 30 knots, Rickover asserted that the submarine’s performance would be hindered above 24 knots. Twenty knots was the maximum speed at which active sonar could still function effectively.
Rear Admiral Levering Smith, head of the Navy’s Strategic Systems Projects Office, was a big advocate of low risks and of relying on existing technology for the hull design. However, he was also a proponent of larger missiles to attain greater ranges, which in turn would require larger missile tubes than on previous classes.
During this period of evolution, the TRIDENT program attracted the attention of Vice Admiral Hyman G. Rickover, who challenged Smith's conception of TRIDENT. Rickover, then approaching seventy years of age, was another of the Navy's remarkable, even legendary figures and perhaps the only one who could match Admiral Smith's technical reputation. If Smith had helped develop POLARIS, Rickover had developed the more fundamental technology of nuclear propulsion.
The nuclear submarine constituted a revolution of sorts within the traditional Navy that had come only with the exercise of great technical, managerial, and political skill-and with the display of enormous will. Smith's great achievement depended on Rickover's before him. Thus when the two admirals locked horns, it was a major event for the Navy.
The issue between Rickover and Smith was joined in technical terms over the size of the reactors. During the late 1960's, Rickover had successfully developed the natural circulation reactor (NCR) which, by operating without the use of noisy pumps at low speeds and requiring less use of pumps at higher speeds, provided a significant improvement in quietness. Rickover had even deployed one in the experimental attack submarine Nanuhal, which was commissioned in 1969.
Recognizing the importance of quietness, Smith wanted access to data on the NCR as a candidate for TRIDENT and thought that the 17,000 shp Nanuhal design provided adequate power. Rickover, however, proposed to develop a far larger natural circulation reactor which would offer not only the increased quietness, but also greater top speed. The analytic trade-off was that a boat using Rickover's reactor would have to be far larger-and more expensive-than the SPO design.
It is always better to go faster, Rickover argued, even if the systems analysts could not imagine why. The commanders of operational submarines, always reliable advocates of speed, agreed. Behind the argument, however, lay a critical fact: if the new reactor were used, Rickover would have substantial authority in the TRIDENT program. On the other hand, if an existing reactor design like the Nanuhal's were used, SPO would have maximum control over the entire boat, including the engine room, as it had in the POLARIS program.
In 1969 the Defense Department Appropriations Subcommittee of the Senate made the first conscious Congressional cut ever in the SSBN program and thereby disrupted extensive scheduling plans. With the great authority and prestige of the Special Projects Office already being sapped by struggles with Congress over the POSEIDON program, Smith could not afford a major fight with a coalition of Rickover and the submarine commanders.
By 1970 he deferred to Rickover; the result was a TRIDENT submarine design of massive proportions. The projected boat would have a 30,000 ton displacement and would be powered by two 30,000 shp reactors, which would be over three times the size of the POSEIDON boat, with four times the power and a top speed of about twenty-five to twenty-seven knots, making it still slower than modern attack submarines. Rickover and Smith reached an agreement that the new submarine would have missile tubes 3.5 times larger in volume than the Poseidon tubes, haing a 50-foot hull.
These specifications were ultimately rejected by the Deputy Secretary of Defense. Even informal discussion of the behemoth design was sufficient to inspire outrage in Deputy Secretary of Defense David Packard in late 1970. Perceiving such signals of trouble, then Undersecretary of the Navy John Warner and Chief of Naval Operations Admiral Elmo Zumwalt knew that they would have to force a redesign, and they began to probe for options.
Warner's and Zumwalt's intervention produced a classic compromise rather than a range of options. Some Navy analysts recognized that, given the absence of a known threat to POSEIDON survivability, the construction of a new submarine could wait and that procurement of a longer-range missile for the POSEIDON boats would provide an ample margin of safety.' This option (labeled the EXPO option, for "expanded POSEIDON") would have restored sole control to Smith, however, and would have suspended missile submarine construction indefinitely.
In other words it did not solve the Navy problems, and thus its appeal in terms of strategic logic only served to make it dangerous. Considerable efforts were made subsequently to constrain the fortunes of the EXPO option. When the top admirals held a critical meeting in January of 1971, the unacceptability of EXPO was the only point of major agreement. Needing some constructive solution, Admiral Zumwalt settled on a fallback position which Rickover's office had prepared, a submarine design of 14,000-ton displacement with a single 30,000 shp reactor. The missiles associated with this design were smaller but, through the use of technical advances, still would have extended range.
Under Admiral Elmo Zumwalt, then–Chief of Naval Operations, the new project was renamed “Super 640” and new specifications were proposed. The proposed platform was similar to the original requirements set by STRAT-X but would only have one reactor and a smaller hull than originally anticipated. The most significant change from the STRAT-X was a 10 percent larger missile tube size. Under the supervision of RAdm Lyon, at least loosely a Rickover protege, both the submarine and the missile grew incrementally in size to their current dimensions-the missile by six inches in diameter and four to five feet in length; the submarine by 5,000 shp in reactor output and 4,700 tons in displacement.
While the growth occurred without any change in the perceived threat or in the goals of the system, its significance is very clear. Whereas the missile design in the Zumwalt compromise was very close to the EXPO missile in size and hence vulnerable to suggestions that it be deployed in the POSEIDON submarine, the latest version (now called the TRIDENT 11) is decisively larger and unequivocably requires a larger submarine. Likewise, the larger reactor stilled internal suggestions that the TRIDENT use the existing 30,000 shp reactor then being deployed on the latest nuclear attack submarines.
In April 1971, EB was awarded a $35 million contract to start a submarine design that would adhere to these requirements - the Ohio class.
|Join the GlobalSecurity.org mailing list|