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Editor’s Note: As the U.S. Navy has come to grips with the reality of greatly reduced defense budgets, it has become obvious that the total cost of a ship over its entire life is of more importance than its cost of acquisition. A major portion of life-cycle cost is the expense involved in manning each ship. Naturally, reductions in crew size can result in very significant savings when calculated over a ship’s thirty year service life with a full crew embarked. The Navy’s Surface Force recently has been experimenting with reduced manning of USS YORKTOWN (CG 48) in what they term the Smart Ship project. The nominal complement of that class is about 385, and over the past year or so they have made some good progress in cutting down their manning numbers. All of the attention given to that project, and to crew size reduction in general, has however prompted questions from those outside the submarine community about manning and cost reduction efforts in the Submarine Force. The following article by two submariners on active duty in the Pentagon is in answer to those specific questions.

The end of the Cold War sparked a reevaluation of U.S. defense needs which ultimately triggered budget cuts and a major downsizing. Over the past several years, the Submarine Force has undergone budget cuts at a rate higher than most other warfare areas. The attack Submarine Force is being reduced from a Cold War high of almost 100 SSNs to a force of at most 50 SSNs by the year 2003. Like others, the Submarine Force is renewing its efforts to accomplish its mission with increased efficiency. However, even at the height of the Cold War, with larger ship construction and operational budgets, the Submarine Force strove for efficiency, continuously searching for improvements in the way it designed, built, operated and maintained its ships. As a result of those efforts, today’s nuclear powered submarines provide the United States with a cost effective undersea warfare capability that is second to none. While they represent nearly 30 percent of the Navy’s combatant ships, submarines are manned by only 9 percent of the Navy’s people and use about 12 percent of the Navy’s budget. Throughout its history the Submarine Force built a tradition of innovation, carefully adapting emerging technologies to maximize its undersea warfare capability. Building on that tradition, ongoing efforts to streamline manning, minimize the cost of ship design and modernization and decrease life-cycle costs, promise to keep the Submarine Force stealthy, combat capable and affordable into the next century.

Manning Efficiencies

Submarine crews, by necessity, have always been small. However, even as hull size increased to accommodate greater combat capability, the crews did not grow proportionally. World War II fleet boats displaced about 1500 tons and were manned by approximately 80 men. Today, a 688 class SSN displaces 6900 tons and is manned by 141 men; a 3(i() percent increase in displacement but only a 70 percent increase in manpower requirements. Submarine displacement and crew size peaked with the commissioning of the first Trident submarine, USS OHIO. Large by comparison to other classes, the 18, 750 ton Ohio class submarine goes to sea combat ready with a crew of only 143. Pan of this manning efficiency comes from submariners performing double duty. Almost everyone onboard a submarine is a watchstander; there are no special damage control personnel, no master-at-arms force, barbers, postal clerks or the like. Submariners have always performed these functions as collateral duties.

Today, even as the complexity of our submarines and their missions increases, the concept of minimal manning is supported by exponential advances in the commercial information technology sector. In addition to the automation of some specific skills, major improvements are being made in the ability of personnel to access, process and move the large amounts of information they need to do their jobs. Local Area Networks or LANs, have been installed in about 50 percent of our commissioned submarines and have been designed into the newer Seawolf and NSSN classes. These systems link the ship’s fixed computer systems with portable lap-top type computers which are in wide use throughout the ship. This use of LANs has helped minimize watch station manning requirements and reduce the crew’s administrative burden, in addition to providing excellent training and logistics resources.

As the Submarine Force welcomes the recently commissioned USS SEAWOLF, first of a new class of attack submarine, it continues its tradition of manning efficiency. Although SEA WOLF displaces more than a Los Angeles class submarine, it has fewer watch stations. Similarly, SEAWOLF’s successor, the New Attack Submarine (NSSN), is being designed with further watch station reductions. The application of technology and automation through- out the NSSN will enable a reduction of 15 additional watch stations over SEA WOLF. Some examples of NSSN reductions include:

  • Ship Control Station: The NSSN digital fly-by-wire advanced ship control station will be operated by a Pilot, Copilot and a Relief Pilot. These three watch standers replace the traditional Diving Officer, Chief of the Watch, Helmsman, Planesman and Messenger used on previous submarine classes.
  • Navigation-Quartermaster Watch Station: The increased use of automation such as electronic charts, allows combining the Navigation Electronics Technician and the Quatermaster of the Watch into a single Navigation Watch.
  • Throttleman-Reactor Operator Watchstation: Increased use of technology and automation allows the Reactor Operator to perform the duties of the Throttleman as well as his traditional duties.
  • Auxiliaryman AR Watch station: The relative simplicity and innovative automation of the NSSN engineroom will allow engineroom personnel to monitor installed auxiliary equipment, eliminating the Auxiliaryman Aft watch station.
  • Torpedo Room Watch: Automated systems and tours by other watch standers allow the elimination of the Torpedo Room watch stander.

In general, submarines have had, and are maintaining, a history of manning efficiency. They traditionally have lower manning per thousand tons of displacement than other combatant types. Although this comparison does not measure a ship’s contribution to the national military strategy, it does exemplify the submarine’s low manpower requirements. Continued reductions in required watch standers for new submarine designs demonstrates a commitment to operational affordability by applying technology and automation when it makes sense, when it does not compromise combat capability and when it is consistent with the Force’s high standards of safety and reliability.

Modeling And Simulation: Rapid Prototyping with Large Scale vehicles

From the conception of USS NAUTILUS, the Navy designed and built eighteen classes of nuclear powered submarines. In some cases, these were single ship classes serving as both fleet combatants and as test platforms for various technologies. In today’s fiscal environment however. the cost associated with the design and construction of a modern submarine, as well as a 16 year acquisition cycle, renders the full scale prototyping of submarines fiscally untenable. Accordingly, the Submarine Force has aggressively pursued various methods of modeling and simulation as an alternative to full scale prototyping.

In one of its most successful modeling efforts, the Navy’s Acoustic ‘Research Detachment in Bayview, Idaho uses that state’s largest natural body of water, Lake Pend Oreille, as a test environment for large scale models. Hundreds of miles from the nearest ocean, this 43 mile long lake combines deep depth, low ambient noise, large unobstructed operating areas and still waters to provide an environment conducive to the development of advanced sensors and submarine stealth improvements.

Starting in 1967, a quarter scale model of the Sturgeon class nuclear attack submarine was introduced to test acoustic silencing capabilities. The success of that effort Jed to the development and construction of a specialized, quarter scale, Large Scale Vehicle (LSV) designed to support propulsor development for the super-stealthy Seawolf class. It took approximately four years of LSV testing to evaluate Seawolfs propulsor design at a cost of about $158 million, which includes the acquisition cost of the LSV. Had the same testing been performed on an actual ship, the estimated cost in time and money would have been about eight years and $863 million. Overall, the Acoustic Research Detachment’s large scale modeling capability has saved the Navy approximately $1 billion in development costs. From the Fleet Commander’s perspective, the savings achieved are actually higher, since submarines not assigned to test and evaluation roles are available to perform forward presence and combat missions.

While the LSV is currently being used to develop the propulsor for the NSSN. the Naval Sea Systems Command (NAVSEA) is designing an improved Large Scale Vehicle. LSV-2. Larger than the original LSV, its scale factors will provide designers with even greater prototyping capability since it will have the volume to accommodate a wider variety of test components. The LSV based “Rapid Prototyping” of submarine control surfaces and propulsors. as well as evaluating internal components, acoustic signatures and wakes will allow the Submarine Force to continually improve stealth and combat capability in a more affordable manner.

Maintenance Efficiencies and Operational Availability

As the Cold War competition increased in the early 1960s. U.S. leaders placed more emphasis on nuclear powered submarines when they recognized that submarine stealth. speed and firepower were required to counter the Soviet threat. Unfortunately, the mounting cost of submarine maintenance began to jeopardize the Navy’s ability to maintain a force structure adequate to meet expanding operational commitments. While existing maintenance practices were effective in ensuring safe and reliable submarine operations. they were far from efficient. Accordingly, submarines spent more than 25 percent of their life cycle time in major depot availabilities. Several factors contributed to this undesirable situation:

  • Early reactor core designs had relatively short lives, necessitating major refueling overhauls after only 43 months of reactor plant operation.
  • A standard baseline overhaul work package did not exist.
  • Technical guidance available to shipyard planners was inadequate and promoted the thought that submarine maintenance was intended to restore all ship’s systems to a like new condition rather than meeting specific operational specifications.
  • Maintenance at the depot, intermediate and ship levels was not integrated.

In response to the protracted duration and high cost of submarine overhauls, in March 1967 NAVSEA began to develop an array of innovative programs to cope with the complex business of overhauling nuclear submarines. The first order of business was to instill greater order, uniformity and control in shipyard avail-abilities to reduce the cost and length of submarine overhauls. This was done by developing complete and integrated Ship Overhaul Work Packages for all non-nuclear work. The packages included all detailed plans, procedures and long lead time materials required to overhaul a nuclear submarine. Costs were reduced by improved work planning that reduced escalating work packages.

In the 1970s, NAVSEA developed a formal life cycle Class Maintenance Plan (CMP) for all SSNs. The CMP identified all the preventive maintenance to be done throughout a submarine’s life, specified its periodicity and assigned its accomplishment to the appropriate maintenance activity. Ship alteration packages and corrective maintenance could be added to the CMP-required preventive maintenance, to produce a consolidated work package for any given submarine availability. The CMP was initially based on conservative engineering judgment rather than detailed historical data. To refine the plan, procedures were developed to collect material condition data on submarine components disassembled for preventive maintenance during the operating cycle. NAVSEA successfully used CMP implementation to:

  • Create a comprehensive maintenance program.
  • Develop a process to formulate detailed availability work packages.
  • Use the rigorous analysis of material condition databases to update both maintenance programs and baseline availability work packages.

The next step in improving submarine maintenance efficiency was to capitalize on these new systems while preserving submarine safety and reliability.

Following four years of detailed data collection, engineering analysis and component maintenance extensions, the Chief of Naval Operations approved the first Submarine Engineered Operating Cycle (SEOC) for Permit and Sturgeon class SSNs. The operating cycle (the time.between shipyard overhauls), increased from 43 to 70 months. NAVSEA’s system was now paying dividends. Submarine time in shipyard overhauls dropped to 22 percent representing an increase of 18 months of operating time over a submarine’s life cycle. These operating cycle extensions have continued, the most recent being implemented in 1995 for Los Angeles class SSNs that now have a 120 month operating cycle. Using the SEOC process, NAVSEA nearly tripled the original SSN operating cycle, reducing submarine time in shipyard overhauls to an impressive 11 percent.

While these maintenance improvements evolved, Naval Reactors (NAVSEA 08) worked continuously to increase the life of reactor cores. Their efforts were so successful that New Attack Submarine class ships will be built with reactor cores that will power these ships throughout their lives. Not only is the cost of refueling NSSNs avoided, but naval architects also have greater design flexibility since the ship design does not need to be optimized for refueling operations. These improvements in maintenance and reactor core life have significantly improved attack submarine operational availability.

Ballistic Missile Submarines (SSBN)

Although previous classes of SSBNs duplicated the SSN’s maintenance successes, the Ohio class Incremental Overhaul represents a new breakthrough in maintenance efficiency. The Ohio’s revolutionary life cycle maintenance strategy accomplishes overhauls progressively during refit periods between patrols, thus reducing required shipyard availabilities. Additionally, the ship’s design played an equally important role in improving maintenance efficiency. Specifically, ample equipment accessibility inside the ship, equipment quick-disconnect and fit-up provisions, well- planned removal and installation pathways all facilitate internal maintenance operations. Further, large diameter logistics hatches which are removed during in-port maintenance periods, provide ease of equipment movement into and out of the ship. On ship classes without these logistics hatches, time consuming hull cuts may be required to remove major components.

The Ohio CMP has been improved using the same material feedback system found in the SSN program. In 1993 the Ohio CMP was revised to reflect periodicity extensions of 518 maintenance items and the deletion of 170 overhaul requirements. Between 1986 and 1995, the number of depot level maintenance items underwent a staggering reduction from 350 to 111 Accordingly, because of the small number of remaining depot maintenance items, Ohio class ships have significant flexibility in scheduling shipyard availabilities, now known as Extended Refit Periods (ERP). ERPs are performed at the 14 year point in the OHIO class life cycle to accomplish shipyard level maintenance that cannot be performed during the normal 35 day refit periods between each 70 day patrol. The results of the CMP strategy are remarkable. Ohio class submarines have reached 92.2 percent operational availability.

Nuclear submarine maintenance is an unprecedented success story that continues to evolve. The successes of the submarine maintenance system have been incorporated into the NSSN design. In addition to reductions in depot maintenance time and a reduced maintenance burden, significant financial savings have been achieved as well. To date, a total of $3.9 billion in shipyard level material and labor costs have been avoided because of the SEOC. This translates to $20.1 billion in savings over the anticipated life cycle of the entire Los Angeles class. Ohio class ships have seen proportional savings with $275 million in maintenance and modernization costs avoided to date translating to $2.9 billion in savings over the life cycle of the entire Ohio class. These savings do not include the effective increase in fleet size resulting from the increase in operational availability. The men and women of NAVSEA, their supporting agencies and submariners in the fleet have made nuclear submarine maintenance a streamlined, cost effective program without adversely affecting safety, reliability or material readiness.


President Truman once noted that “The United States is preeminent among nations in the development of industrial and scientific techniques … our imponderable resources in knowledge are constantly growing and are inexhaustible.” By designing and building the world’s first nuclear powered submarine, and by developing the innumerable technologies necessary to build SEAWOLF and design the NSSN, the Submarine Force has confirmed President Truman’s assertion. It continues to be a leader in adapting emerging industrial and scientific techniques to improve submarine stealth and combat capability while improving efficiency and maintaining affordability. Despite contradictory claims that submarines are expensive platforms with high acquisition costs, a careful life cycle analysis reveals that submarines are among the most cost effective platforms in the Navy. Moreover, a submarine’s inherent stealth provides force protection without necessitating the construction, manning, operation and maintenance of escort vessels, missile systems or aircraft.

As proud as the Submarine Force is of its record of innovation and efficiency, there is still work to be done. Research continues across a broad spectrum of technologies necessary to improve open system architectures and methods to reconfigure a submarine’s internal spaces to accommodate advances we have not yet envisioned. New operational concepts are also being developed which leverage these improvements and also maximize the effectiveness of existing platforms. Submariners are carefully watching the efforts of other Navy, military and private sector groups for innovations which may lend themselves to improved undersea warfare capabilities.

As its first centenary approaches, we find a Submarine Force composed of minimally manned, efficiently designed and modernized ships with reduced life cycle costs. By any measure, it is a Smart Force that is well positioned to provide the United States with a stealthy, combat capable and affordable undersea warfare capability well into the 21st century.


Please note that USS SILVERSIDES (SS 236) was inadvertently omitted from the list of submarine memorials on page 114 in the April SUBMARINE REVIEW. She is located in Muskegon, Michigan.

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