What is the state of the Navy’s program to develop a follow-on to the current Trident strategic missile submarines—the SSBN(X)? There appears to be two answers: “very good” and “very bad.”1 The Navy is planning to build 12 SSBN(X) submarines to replace the 14 strategic missile submarines of the Ohio class that are scheduled to be retired at the rate of one per year between Fiscal Years 2027 and 2040. The planned follow-on SSBN(X) submarines would become operational at the same rate beginning about 2029. Thus, from about 2029 to 2041 the projected SSBN force would drop below the goal of 12 submarines.
Twelve new missile submarines are planned because the SSBN(X) design calls for a nuclear-fuel core that would last the service life of the submarine, i.e., some 50 years. Thus, unlike the Ohio-class SSBNs, which are planned for a 40-year service life, the new missile submarines would not have to be taken off-line for two years for refueling.
The major issue facing the SSBN(X) program—according to those who feel that the program’s status is “very good”—is cost. Eric Labs of the Congressional Budget Office has provided a valuable analysis of the cost situation: The Navy’s 2007 and 2008 shipbuilding plans assumed that the first SSBN(X) would cost $4.8 billion (in 2012 dollars) and that follow-on ships would cost $3.6 billion each; the 2011 plan estimated the SSBN(X) average cost to be $7.7 billion each, which was reduced in the 2012 plan to $6.5 billion per ship. Labs astutely observed:
That cost history highlights the uncertainty that remains in determining how much a future class of SSBNs will cost. Those figures also highlight the great expense of replacing the current ballistic missile submarines and the effect that doing so could have on other shipbuilding programs or on programs other than shipbuilding.2
Navy officials in October cited a cost of $4.9 billion per follow-on ship, a 25 percent reduction over the Navy’s plan put forward a few months earlier.3 These cost reductions were to be achieved by:
• reducing the number of missiles from 20 to 16 (compared with 24 in the Ohio-class SSBNs)
• reducing missile-tube diameter from 97 to 87 inches (compared with the 83-inch Trident D-5 missile in the Ohio class)
• deleting the “chin” sonar array
• reducing the sail/mast requirements
• reducing torpedo capacity
• adopting various features from the Ohio- and Virginia-class designs.
The basic characteristics of the submarine planned as a result of these cost reduction efforts are shown in the accompanying chart.
The proposed SSBN(X) thus would be larger than the Ohio design, but with one-third fewer missiles. This appears incongruous as “things” are becoming smaller and more powerful—today’s handheld smart phones have more computing capability than was used to land a man on the moon in 1969. In the past a rationale for larger submarines was their quieting features; now advanced acoustic quieting features should require less space.
Of more concern to some observers is the non-acoustic quieting of the SSBN(X). For example, instead of the retracting bow planes of the later Virginia-class submarines, the SSBN(X) is planned to have sail-mounted (fairwater) planes. Sail-mounted planes without special mitigating features create vortexes that can be detected by above-surface sensors.
Of great concern to those observers who feel the SSBN(X) program is doing “very badly” is the conventional design of the new submarine and the adoption of major components of the Ohio and Virginia classes. The Ohio concept design began in the late 1960s with the STRAT-X study into future U.S. strategic systems; the Virginia design dates to the mid-1990s, when it was initiated as a lower-cost, less capable alternative to the Seawolf (SSN-21) attack submarine.
To employ the design concepts and components of these submarines ignores the probable developments in antisubmarine warfare (ASW) between now and 2080—the estimated service life of the SSBN(X), i.e., almost 70 years into the future. If one looks back 70 years to the early 1940s and the “fleet boats” then being constructed by the Navy, one can begin to understand the potential change in the naval environment in the coming decades. For example, the past 70 years have seen the development of the German Type XXI submarine, the closed-cycle systems that were the progenitor of today’s air-independent submarines, nuclear propulsion, the revolutionary German GHG array sonar, satellite detection of submarines, underwater-launched missiles, and so on.
Further, the United States was continually surprised by Soviet developments in submarines/ASW during the Cold War. Among these were submarine speeds and operating depths, reactor power density, the SS-NX-13 antiship missile, 26-inch-diameter torpedoes, the Shkval torpedo, the high degree of automation, the use of polymers, and, especially, non-acoustic submarine detection.
Thus, when one considers the pace of technological development—especially in computers, sensors, and satellites—the current approach to the SSBN(X) design that has cost reduction as a primary goal becomes questionable. Despite strategic deterrence being a high national priority, and the strategic missile submarine having great advantages, especially in survivability, over land-based strategic weapons (missiles and manned bombers), the current U.S. financial situation argues against building the best missile submarine possible at this time. This is especially true if the congressionally mandated sequestration comes into effect, further cutting defense budgets.
Because the 14 Trident submarines will have to be retired beginning in the late 2020s, an alternative approach to the future SSBN force must be considered. A proposed alternative that is gaining momentum among some members of Congress is to delay construction of the “proper” Ohio replacement, i.e., a fully capable, low-signature, 20-missile submarine, for several years until the U.S. financial situation improves or is at least stabilized. The alternative is to expand the ongoing Virginia SSN program to provide a near-term, lower-cost SSBN(X). For example, General Dynamics/Electric Boat has proposed the construction of a “stretched” Virginia-class submarine to carry up to 194 Tomahawk cruise missiles. This proposal provides for a 94-foot “plug” to be inserted amidships. It would add some $500 million (FY 2011 dollars), increasing the cost of the submarine by some 20 percent. (Use of a missile compartment “plug” was the manner in which the Skipjack [SSN-585] design was adopted for the Navy’s first Polaris strategic missile submarines.4)
The proposed Virginia-derived SSBN would carry a Trident C-4 size missile. As no C-4 missiles are available, the production line would have to be restarted or a new missile developed based on the C-4/D-5 missiles and technology available since the D-5 entered service in 1990.
The Virginia SSGN proposal provides four 87-inch diameter tubes for a total of 28 Tomahawk missiles (plus 12 missiles in two bow tubes). A Virginia SSBN probably would have 12 tubes, possibly 71 inches in diameter (i.e., C-4 missile size).
While such a missile program would have costs, it would be offset by the lesser cost of adopting the Virginia design instead of developing the completely new, much larger SSBN(X) design. Also, spare parts and maintenance as well as personnel training and assignment costs would be far less if the Virginia program were expanded. The Virginia-class submarines are being produced on (or ahead of) schedule and at planned cost, in contrast the oscillating cost estimates of the current SSBN(X).
Further, should the international strategic situation deteriorate in the near future, the production of Virginia-derived SSBNs could easily be accelerated by shifting Virginia SSN resources to the missile submarine program, with the current U.S. shipbuilding capacity capable of producing four Virginia SSN/SSBNs per year.
Perhaps the greatest danger in adopting the Virginia design to the strategic role is that these missile submarines could be a major success and thus delay the construction of advanced-design SSBN(X)s. But that risk is small considering the U.S. financial situation that has already caused a two-year delay in the Ohio replacement program and is forcing the construction of what may be a less-than-optimal strategic missile submarine. The United States should not use 20th-century submarine concepts to move toward the 22nd century.
1. Some Navy officials contend that “the Ohio replacement,” not “SSBN(X),” is the proper terminology. Both are used by the Navy—and in this column.
2. Eric J. Labs, An Analysis of the Navy’s Fiscal Year 2013 Shipbuilding Plan (Washington, DC: Congressional Budget Office, July 2012), 16–17.
3. CAPT William Brougham, Ohio Class Replacement Program Manager, Naval Submarine League Symposium, Arlington, VA, 18 October 2012.
4. Existing Skipjack-class submarines under construction were not “cut in half” and the Polaris missile compartment inserted, as popular myth contends; the “cutting” was done on blueprints.