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[Editor’s Note: More than 10 years ago the Navy began concept definition for an attack submarine follow-on to the SEA WOLF class. In the early 1990s, the process matured to the point of requesting formal approval for the new attack submarine. After several delays, the NSSN Defense Acquisition Board (DAB) was held on 12 January 994.

Dr. Deutch’s DAB decision memorandum requested an outside panel of experts is assembled to review the NSSN’s baseline design’s ability to perform its military missions from the viewpoint of its major characteristics. In response to that request, Ms. Slatkin, the Assistant Secretary of the Navy (Research, Development, and Acquisitions) established the New SSN Independent Review Group (INRG). The panel members. chosen by Dr. Deutch and Ms. Slatkin were: Stephanie Coulter, Frank Fernandez, David Heebner, Benjamin Huberman, Reuven Leopold, Chester Long, Peter Palermo, and William Wegner. The panel was chaired by Vice Admiral J. Guy Reynolds, USN(Ret.).

The findings of that Group resulted in a report to Dr. Deutch, DAB principals, and Navy leadership. The following article provides unclassified highlights of that secret report. Material presented in frames are INRG briefing slides ·with comments by Guy Reynolds.]


At the 12 January 1994 New Attack Submarine (NSSN) Defense Acquisition Board, Dr. John Deutch acknowledged that a nuclear attack submarine program is vital to our nation’s security. He subsequently stated that “it is essential that we have the strongest possible rationale for proposed modernization programs if we are to be successful”. In a 24 January 1994 memorandum, Dr. Deutch requested that the Secretary of the Navy undertake three actions to support the NSSN program milestone.

As one of the actions, Dr. Deutch sought the Secretary’s assistance in assembling an independent review group to examine the ability of the NSSN design to perform its required military missions. Additionally, the review was to “to provide an independent check that we have asked all the right questions”.

Ms. Nora Slatkin, ASN(RDA), appointed an outside group of technical experts to review the NSSN baseline design. That group met for several months starting on 1 March 1994. The group received briefings on every aspect of the NSSN design, including the threat the submarine will likely face and the missions considered appropriate for a nuclear attack submarine. The requirement for affordability caused the group to explore timing and industrial base issues.

In the early stages of the process, the group developed a set of “hard questions” to respond the Dr. Deutch’s charge. Those questions first considered the acceptability of the baseline speed and in tum examined the justification for SEA WOLF acoustic quieting across the NSSN speed range. Additionally, the questions were framed to stimulate “fresh thinking, with respect to traditional versus emerging submarine roles and missions. As a result, vulnerabilities and requirements associated with extended operations in the littoral battlespace were specifically examined. Cost-saving trade-offs in speed, payload, and combat systems were brought under close scrutiny. Lastly, the review group sought to identify those characteristics that must be established before the Milestone decision in contrast to the parameters that are more suited for definition during preliminary design.

In preparation for the Group’s deliberations, I drafted an approach to provide a logical progression through the large volume of information necessary to review the New SSN’s characteristics. The approach structured an examination of the projected missions, threat environments, and the appropriate portions of the Department’s Bottom-Up Review.

With the foundation in place, the panel set about examining the specific characteristics as defined for the DAB by the Operational Requirements Document.

Since affordability was the driving motivation behind design tradeoffs, a clear understanding of cost factors and Industrial Base issues was fundamental to panel deliberations.

The briefing to Dr. Deutch focused on the conclusions and recommendations with a significant amount of backup to support the panel’s findings including the answers to questions raised about the New SSN program during pre-briefs to the DAB membership.

Conclusions -Top Level

  • NSSN program is consistent with Department of Defense objectives (Bottom Up Review)
    • Preserves the Industrial Base
    • Addresses New Mission Requirements
    • Maintains Force Level Options
    • Reduces Cost
  • There are no Emerging Technologies on the horizon that warrant delay of NSSN

The panel unanimously found that the New SSN program supports expected missions against the projected threat of the 21st century.

The panel devoted a significant amount of time reviewing Emerging Technologies. Two and a half days were spent in round table discussions with representatives from ARPA. the Office of Naval Research, and Naval Reactors.

Briefers were requested to categorize their efforts by the level of maturity and potential for meaningful contribution to submarine performance. They were asked to specify during which time period (Present to 1998, 1998 to 2005, and 2005 to 2015) each technology would potentially be available for transition to the start of Engineering and Manufacturing Development.

Many of the technologies examined are exciting and hold promise for the future. However. it was the opinion of the scientists that with one exception, none of the· technologies were at a level of maturity that warranted consideration for inclusion in the NSSN design. That one area identified was the Light Weight Wide Aperture Array technology.

The panel concluded that NSSN program delay to accommodate emerging technology is not warranted. This is one of the key findings of the panel.


  • Conclusions
    • Top Level
    • Characteristics
      • Speed
      • Signature
      • Payload
      • Combat Systems
    • Cost Considerations
      • Lower cost submarine
      • Industrial Base
      • Timing/Force Structure
      • Innovatlive Acquisition Approach
  • Recommendations

The panel examined the trade-offs between individual characteristics and the trade-offs between characteristics and cost.

Each characteristic will be discussed individually. However, it is extremely important to recognize the synergism between the characteristics. This synergism allows performance retention while backing off on individual performance characteristics.

Synergism between speed, acoustic signature, and combat system performance is especially significant. Submarine superiority is dependent upon the establishment of “tactical control” across a wide spectrum of scenarios in varied environmental situations including high-speed transit, deep ocean search, and operations in shallow water.

NSSN characteristics were examined individually beginning with speed, then moving on to signature, payload, and then combat systems. At each step, the synergism between characteristics was reexamined.

Conclusions – Speed

  • Speed is a characteristic that is very difficult to increase once design is established.
    • Must be specified as a design requirement at Milestone.
  • Speed drivers – evasion, mobility, search
  • Evasion – most discriminating factor
  • Trading speed for lower cost emphasizes necessity for retaining tactical advantage
  • Submarine Quieting – Combat System/Sensors balance critical

Speed Trade-off Acceptable
Maximum Speed 2>=28 knots is satisfactory

The New SSN design trades speed for cost.

The strong relationship between speed and shaft horsepower dominates ship size. Conversely, for a specific shaft horsepower (determined by the maximum speed requirement), the relationship between speed and displacement provides considerable latitude in ship size. Examination of the facts shows that ship size is a function of the combination of speed, signature (quieting), and payload. It is just not possible to have a small, fast, quiet ship with a reasonable payload.

Given the relationships between shaft horsepower and size, and with an understanding that speed is one of the characteristics that must be specified at Milestone I, the review group closely examined the factors that contribute to the selection of maximum speed.

The speed drivers are mobility, search, and evasion. Of these, evasion is the most discriminating characteristic.

This curve describes the probability of counter kill during an engagement. By dividing this graph in half, two interesting facts emerge:

  • For some engagement ranges evasion speed is not dominant. Details classified.
  • For other engagement ranges evasion speed is the most important survivability. Details classified. (In all scenarios a higher evasion speed continues to improve survivability.)

The review group concluded that the trade-off of speed for cost was justified when other factors contributing to maintaining tactical advantage are considered.

An understanding of the synergism between speed, acoustic signature, and combat system performance is necessary to support the conclusion that the trade-off of speed for cost is acceptable. Specifically, by maintaining a platform with SEA WOLF level of acoustic quieting and a complementary combat system, the platform can engage the target at preferred ranges outside “W, kids, supporting the trade-off in maximum speed for cost.

Conclusions – Submarine Signature

  • Acoustic radiated signature is a characteristic that is very difficult to improve once the design is established
    • Must be specified as a design requirement at Milestone
  • Acoustic quieting is a central characteristic of mission performance and survivability
  • 6881 quieting – inadequate against the projected threat
  • “SEA WOLF quiet” acoustic signature is necessary
    • Supported by threat requirement
    • Justified across NSSN speed range

“SEAWOLF Quieting” is essential

The signature is addressed in two slides. Like speed, the acoustic signature is a characteristic that must be specified at Milestone I.

Acoustic quieting is central to total submarine system performance: search, attack, and evasion.

688 and 6881 class submarines are limited by platform noise.

U.S. submarines maintain success in encounters with Russian AKULAs because of the margin provided by sensors and onboard electronics.

Early 80s advances in enemy submarines and weapons prompted a dedicated research and development effort that culminated in “SEA WOLF quieting”. NSSN is benefiting from that research. Without the advances made in SEA WOLF, it would not be possible to build an NSSN sized submarine with SEA WOLF quieting across the speed profile.

The review group concluded that SEA WOLF quieting is an essential characteristic for the NSSN based on the current and projected threat.

The necessity for SEAWOLF guieting is another key finding.

Conclusions – Submarine Signature

  • “Stealth” means much more than acoustic quieting
  • Low frequency active acoustic (LFAA) threat emerging
  • Littoral operations increase other non-acoustic vulnerabilities
    • Electromagnetic detection; MINE THREAT
      • Degaussing capability needed (Circuit “D”)
    • Radar, Infra-red, visual detection

Active Target Strength/non-acoustic vulnerabilities
must be closely examined in preliminary design

The INRG was charged with examining the ability of the NSSN design to meet its intended missions

Much has changed since the initial round table discussions that framed NSSN attributes. Naval participation in Joint Near Land Operations has emerged as an increasingly important mission. The worldwide diesel submarine threat continues to grow and the proliferation of technology increases the risk to some combatants.

The inherent covert nature of submarines makes them especially well-suited for many close-in. hostile area missions.

With littoral operations requirements increasing, the INRG found that more attention must be focused on exploitable signature characteristics other than passive acoustic.

It is the conclusion of the Review Group that the design features associated with NSSN active acoustic and non-acoustic signature require further review during Preliminary Design.

Conclusions – Payload

  • Internal payload is a characteris_tic that is very difficult to alter once design is estab· lished
    • Must be specified as a design requirement at Milestone
  • Payload traded for tower recurring cost
    • torpedo tubes=>smaller ship diameter
    • horizontal stows=>smaller displacement
  • Payload flexibility incorporated in design
    • Reconfigurable weapons room enhances adap-tability
    • Hull design/interface facilitates incorporation of future modifications
    • VLS capacity supports expanded strike role
  • Nuclear weapons capability should be included in design

Payload Trade-off Acceptable
given vertical launcher system

The NSSN design has fewer internal weapon stows than SEA-WOLF. This characteristic coupled with a reduction to four 21 inch torpedo tubes had allowed a significant decrease in the size and cost of NSSN.

The review group examined the weapon demands needed to support the projected NSSN missions.

The panel considers the internal payload is sufficient for the full range of missions. Further, the NSSN design provides increased payload flexibility as compared to previous submarines through the reconfigurable weapons room.

During the payload review, the panel came to the conclusion that the decision to eliminate the NSSN’s capability to carry tactical nuclear weapons was overly restrictive and should be reversed.

The NSSN’s payload reduction for cost savings is acceptable given the inclusion of the reconfigurable weapons room and vertical launch cruise missile capability.

Conclusions – Combat Systems

  • Combat Systems functionality-Milestone I design requirement
  • NSSN requires combat system/sensor suite consistent with it’s signature and mission
  • Developing an open system architecture with appropriate use of COTS/NDI is necessary for affordability and technology insertion
  • Private sector involvement in determining technical approach to open system architecture is necessary
  • Wide Aperture Array fWAAJ is the optimum sensor against the littoral diesel threat

Combat System management and development
the approach requires refinement/redefinition

Speed and acoustic signature are fundamental to NSSN performance. The combat system and sensor suite are no less important to tactical advantage. The combat system design and acquisition strategy proposed for NSSN caused the panel’s greatest concern.

Unlike speed and acoustic signature, the INRG considered definitive decisions on a combat system architecture premature. The rate of the change in electronics technologies is being set by the commercial industry. This situation provides opportunity and flexibility for military application.

NSSN combat system functionality has been adequately described in most areas. The INRG felt that Preliminary design should be used to re-describe the most cost-effective approach to an open system architecture with appropriate use of COTS and NDI.

Strong private sector involvement is necessary at the system level to take advantage of the technology and cost reduction momentum in the private sector.

Additionally, the panel concluded that the Wide Aperture Array, which had been provided space and wight, is the optimum sensor against the littoral diesel threat and should be included in the baseline submarine.

At this point, I would like to comment on the panel and its deliberations.

The panel members are listed in the front of this report (see Editor’s Note). They possessed broad experience in technology, acquisition, and submarine design, construction, and operation. The diverse backgrounds of this group contributed to the intellectual integrity of panel deliberations. During the entire process there was frank, open, and sometimes, spirited discussion. Every issue was pursued to a consensus.

The panel converged to consensus in stages as the study progressed. The cartoon on this slide is a snapshot of the panel after completing the review of threats, missions, and characteristics. The deliberations to this point solidified two conclusions:

  • Advanced nuclear submarines are an essential pan of the U.S. military capability, and
  • Restart of 6881 production could not meet the nation’s future needs due to platform quieting limitations and insufficient design margin for future growth.

Emerging missions in the near-land warfare scenario made a persuasive argument for NSSN.

The case for continued SSN-21 production hinged upon near term cost avoidance of NSSN non-recurring cost.

Conclusions – Cost Considerations
  • NSSN program has responded to the direction for a capable, lower cost follow-on submarine to SEAWOLF
  • NSSN optimized JMA mission requirements at an estimated cost -30% less than the SEA WOLF program
NON-RECURRING 7,089 4,681
1ST SHIP FY89 2,676 FY98 2,237
2ST SHIP FY91 2,192 FYOO 1,843
3ST SHIP FY96 2,499 FY01 1,746
TOTAL 14,456 10,507

JMA -Joint Mission Assessment

At this point, the INRG moved from performance characteristics to cost considerations.

The department bad scrutinized the program cost and found them within estimating standards. The panel did not consider it productive to re-perform that scope of analysis. Recognizing the significant change in future submarine procurement, we decided to examine the cost implications of low rale production.

With that focus, we made a comparison of SSN 21 and NSSN non-recurring and SCN costs for the first three ships. This comparison was made with the understanding that a large portion of the SSN 21 costs as sunk costs.

The NSSN design has made acceptable trade-offs in speed and payload for cost. Those trade-offs have resulted in a smaller submarine that retains the essential level of performance. With respect to the acoustic signature, this is a considerable achievement. SEA WOLF quieting had been maintained in a smaller ship, thus reducing recurring costs.

No attempt was made to estimate the cost associated with modifying future SSN 21 class ships with the littoral warfare attributes planned for the NSSN. The cost savings evident in this comparison make a strong case for moving on to NSSN.


New SSN Design Features

  • Mission focused design improvements
  • Photonics mast
  • Advanced ESM suite
  • Lockout Chamber for SOF
  • Mine hunting sonar (AMDS)
  • Reconfigurable weapons room
  • ASDS/DDS capable
  • Improved Communications suite/antenna
  • VLS strike capability
  • Reliability with reduced redundancy

A frequently encountered criticism of NSSN was that it was nothing more than a “cheap SEA WOLF”. During the characteristic and cost reviews, it became apparent to the INRG that this was far from the case. NSSN was a very different submarine from SEA WOLF. The slide above provides some of the design features that tailor NSSN design for the missions envisioned for the next century.

A more correct characterization of the NSSN design is a flexible submarine design that retains traditional submarine capability, meets littoral warfare needs, and provides long-term flexibility while taking advantage of technology to become more affordable.

At this point in the deliberations, the INRG came to the conclusion that it was important to move on to NSSN as rapidly as possible.

The question to be resolved was one of timing, not one of whether it was in the best interest of the United States to move forward with NSSN. The combination of threat, characteristics requirements, cost and industrial base issues convinced the panel that NSSN was more than justified, it was needed.

Conclusions – Cost Related Factors
Industrial Base Observations
Uncertainty Jeopardizes Vendor Base


    • Nuclear component manufacturers – sharp decline
    • Non-nuclear component suppliers leaving market
    • Production capability threatened


Production Bridge Provides Continuity


      • SSN23 in FY96 is essential
      • CVN76 supports nuclear skills


Industrial Base transition to NSSN dependent on
SSN23 in FY96

The panel received Industrial Base inputs from Newport News, General Dynamics, four non-nuclear vendors, and government representatives. The draft RAND study (March 1994) was studied and provided valuable insight.

The conclusion of the panel was that the submarine industrial base, especially the vendor base, is extremely fragile. SSN 23 authorization in FY96 and NSSN authorization in FY98 each play an important role in the maintenance of the submarine industrial base.

SSN 23 authorization in FY96 is necessary to provide the production bridge to NSSN construction in this century or early in the next century.

NSSN authorization in FY98 is necessary to provide an indication of government commitment to continued nuclear submarine construction. The hope of low rate SEA WOLF production or the promise of restarting the 6881 production line does not provide the necessary confidence to encourage the fragile vendor base to stay the course. Without an indication of commitment, the long list of submarine unique vendors that have left the marketplace would grow to the point that reconstruction of the base necessary to remain a superior submarine nation would be prohibitively expensive, if possible at all.

Conclusions – Cost Related Factors
Timing/Force Structure Observations
  • Draft RAND study (18 March 1994):
    • “Less than a billion dollar savings given longest gaps feasible.”
    • “Further risks may jeopardize nuclear submarine program”
    • “Recommend continued submarine production”
  • FY98 Authorization needed to maintain
    minimum force structure

    • One year delay removes decision maker’s force level options
    • Delay makes “10-12 by 2012” Joint Staff objective unachievab
  • Low rate NSSN production signals long term commitment
    • Provides stability during industry restructure
    • Preserves submarine design capability

Production Gap savings do l1Qljustify the risk
– FY98 NSSN recommended

The draft RAND study encourages continued submarine production over a suspension or Gap approach. Further, RAND identifies a minimum acceptable time between consecutive submarine delivery.

The FY98 NSSN authorization accommodates this interval. The case for the FY98 start becomes more persuasive when examined from a building rate perspective.

A delay from the strategy of record increases cost and extends the production time of the lead ship by four years. First ship delivery in 2009/2010 removes long-range force planning flexibility and jeopardizes the Joint Staff objective of 10-12 submarines with SEA WOLF quieting by 2012.

SSN 23 construction provides the near Tenn bridge to the vendor and production Industrial Base. A concurrent area of concern is the white-collar knowledge base. Without both SSN 23 in FY96 and NSSN in FY98, the United States’ ability to maintain worldwide submarine superiority will be in question.

The third key finding is that a production gap is extremely high-risk not justified by projected savings.

A “Fill in the Gap” strategy has been proposed by some as a solution to the knowledge base problem. The theory is to fill in lean years with make work designs or study projects. This approach was believed to be seriously flawed by the INRG. The drawbacks are:

  • Executability is questionable:
    • Aggressive. innovative engineers are not attracted by make work projects with no end product.
    • Hiring rate of 250 per year is unachievable even with gap fill
    • Experience level of the design force is inadequate.
  • Spending $200M per year for make work effort would be extremely difficult to defend in any fiscal climate.
  • The essential characteristic for U.S. weapon systems is superiority. The make work approach will not achieve this key objective.
  • Embracing a “Fill in the gap” strategy sets a dangerous precedent for other troubled defense industries.
Conclusions – Cost Related Factors Innovative Acquisition Approach Observations

  • Low Rate Production necessitates adjustments in acquisition policy.
  • Traditional acquisition requirements/regulations are not suited for restructured submarine industry
  • Integrated Product & Process Development (IPPD) shortens design time/reduces cost
    • Concurrent Engineering: event based, product driven
    • Phasing replaced by seamless engineering process
    • Cross functional desing/build teamwork approach
    • Team players: government, shipbuilder, suppliers, operator

Integrated development approach valid for NSSN
Government participation is a key factor

The INRG came to the conclusion that the necessary transition to low-rate production provides an opportunity as well as a challenge. There has been a lot of focus on the challenge. NSSN production by a single entity provides the opportunity for an innovative acquisition approach that reduces administrative churn and cost. Strong private sector teams working together to·minimize administrative churn, optimize schedule and make engineering trade-offs provide the best chance to control change and manage cost.

An integrated development approach with the builder, combat system prime and government sitting at the same table is an opportunity too good to pass up.


1. USD(A& T) Grant Milestone I Approval to Proceed
2. Support FY98 Authorization of the NSSN following the SSN23 in FY96
3. Characteristic refinement during preliminary design:
a. Establish MS I exit criteria for active and non-acoustic signatures and information exchange capabilities
b. Conduct a review of the Combat System acquisition strategy and develop an approach that optimizes private sector expertise in planning an open system architecture.
c. Identify realignments necessary to consolidate management and funding authority of key NSSN combat systems related programs
d. Include a nuclear weapon capability in the baseline
e. Include the Wide Aperture Array in the baseline
4. Designate NSSN as an Integrated Product & Process Development (IPPDJ program

Neither emerging technology nor near term · cost savings justify the high risk of delay

And finally, the Recommendations. The panel concluded that recommendations 1 and 2 are justified by the maturity of the NSSN program and are necessary to maintain a viable submarine Industrial Base. Additionally, NSSN is a necessary follow-on to the SSN 23 in order to support force-level objectives with a more affordable platform.

Recommendation 3a will provide the incentive for the Navy to focus on those characteristics that will tailor the NSSN design to match the emerging near-land warfare missions.

Recommendation 3b seizes the opportunity to capitalize on the private sector momentum in open system architectures. The management realignments suggested in 3c will substantially reduce NSSN program risk.

Recommendations 3d and 3e will provide NSSN capability in two essential mission areas.

Recommendation 4 seizes the opportunity to take advantage of the transition to low-rate production

Since the briefings to Dr. Deutch and Navy leadership in May and June significant progress has been made. NSSN successfully completed a Milestone I DAB in I August 1994.

Editor’s Postioeue

Vice Admiral Reynolds included a Chairman’s Summary in the record of the briefing to Dr. Deutch. That summary follows:

Chairman’s Summnary

Dr. Deutch requested that an outside group of “technical experts” review the NSSN baseline design. The panel members selected for the New Attack Submarine Independent Review Group are recognized as authorities in their respective fields, possessing broad knowledge and experience in technology, acquisition, submarine design, construction, and operation. The members answered the call for an independent review with eagerness, professionalism, and impressive clarity of thinking.

Each member approached the research with enthusiasm and thorough investigative skills. During their review, they exhaustively explored numerous analytical studies, the latest all-source intelligence information at the technical and policy level, as well as detailed NSSN engineering data. They closely examined each characteristic and explored the synergism between characteristics. Each conflict was pursued to resolution. In this way, the panel was able to converge to a final set of conclusions and recommendations.

As the briefing of the panel’s work was delivered to Navy and OSD leadership, I was careful to characterize myself separately from this eminent panel of technical experts. My responsibility was to consolidate their findings while ensuring that all the right questions had been considered. Throughout the study, we pursued the common goal of developing an indisputable package of conclusions and recommendations. From my position as chairman, I observed four overarching findings. They are:

  • First and foremost, nuclear submarines remain vital to our National security. Intelligence estimates and numerous studies conducted since the end of the Cold War accentuate the enduring need for these versatile and capable platforms.
  • With the implementation of the panel’s recommendations, the NSSN design is technologically robust and reflects the correct balance between cost and state-of-the-art technology. There is nothing on the horizon that justifies the delay.
  • The industrial base is nearing the breaking point. The lack of a commercial market makes the most fragile elements the nuclear and non-nuclear vendor bases and the submarine designer workforce.
  • A long term commitment is essential to provide stability

during this unprecedented period of restructuring. Lack of government commitment will exacerbate this tenuous situation while risking the preservation of this vital national asset.

I have served with several committees and study groups. This effort stands out as an example of open, competent, professional dialogue. I feel privileged to have been associated with the “panel of experts”.

J. Guy Reynold

Naval Submarine League

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