The Challenge
In the recently completed Bottom-Up Review, Secretary of Defense Asp in made the decision to build the third SEAWOLF at General Dynamics Electric Boat Division, to maintain two private nuclear capable shipyards, and to develop and build the new attack submarine (NAS). The construction of SSN 23 helps to solve the near term issue for the submarine industrial base; however, the long term issue of designing and building an affordable NAS needs to be addressed.
Barring a change in the world political situation, there is no mission requirement to build another submarine until early in the 21st century. Accordingly, low rate production will be the means to maintain submarine design and construction capability for at least the next decade. This situation presents two challenges to submarine designers and manufacturers. First and foremost: future submarines must be affordable. Second, the NAS design must facilitate the evaluation of emerging technologies in anticipa-tion of resumed production due to changes in the threat environ-ment and the eventual obsolescence of the current Submarine Force. The challenge therefore is: How to affordably introduce new technologies in a low rate submarine production environment.
A Winning Strategy
An answer to the challenge can be found by revisiting the historical development of today’s nuclear submarine. The post-World War II approach to submarine acquisition included the building of singular or essentially one-of-a-kind submarines without commitment to long term follow on production. This philosophy produced ALBACORE, NAUTILUS and HALIBUT, to name a few.
- ALBACORE convincingly demonstrated the concept of the tear drop shaped hull to maximize submerged speed. A radically new streamlined hull and a number of innovative ship systems were introduced in this diesel electric submarine that were later incorporated in the SKIPJACK class nuclear submarine.
- NAUTILUS proved the feasibility of a nuclear powered submarine and then served for 25 years as a fully operational attack submarine.
- HALIBUT introduced the concept of a dedicated nuclear powered missile submarine. Equipped with sophisticated navigational equipment and capable of extended deployments, it was a precursor to the Polaris program.
Each of these submarines tested new technologies at sea. Opera-tors provided meaningful feedback for consideration in subsequent designs. This approach fostered conceptual innovation so that when the time came for series production, proven technologies could be affordable integrated into new designs with low technical risks.
To achieve an affordable NAS, the notion of singular submarines should be considered. It is suggested that the NAS be a baseline design that possesses the key attributes of a nuclear submarine: stealth, speed and endurance. This baseline submarine would emphasize modularity and reconfigurability and be receptive to being economically upgraded with new technology.
Modular/Reconfigurable Designs
The notion of modular design is different from the modular construction process used in the TRIDENT and SEAWOLF pro-grams. Submarine modular construction implies that the vessel is constructed from a series of hull cylinder modules that are fabricated and outfitted in a more efficient environment than the traditional method of building submarines on the ways. These modules are then integrated in the shipyard, where system assembly and test are completed.
Modular design differs in that the ship comprises a series of independent system modules. The ship system module package concept allows for the cost effective upgrading of a design since the impact of changing one system does not significantly influence other modules of the submarine.
System upgrades are not new to submarines. However, the cost effectiveness of these upgrades can be improved by advanced planning. The 688 LOS ANGELES class is a classic example of a submarine that could have been most cost effective had modular-ity in design been incorporated in its initial design. The 688 combat system evolved from an analog Mark 113 Mod 10 to the totally digitized AN/BSY-1 system. The upgrades to the combat system significantly altered the internal arrangements of the submarine and affected many other support systems such as ventilation and air conditioning. For current and foreseeable submarines, improvements such as state-of-the-art combat systems and evolving weapons like the Tomahawk vertical launch system (VLS) will continue to be a fact of life. However, we cannot afford a submarine design that requires extensive redesign to support new ideas. Designing future submarines with the provision to support affordable integration of new technologies and mission enhancements is mandatory.
Technologies that maximize the ability to upgrade a submarine cost effectively must be emphasized. Distributed systems that minimize air and hydraulic piping and rely on electrical interfaces will facilitate inexpensive upgrades. Systems should be designed that are self sufficient and do not require extensive modifications to other existing systems to function.
Submarine designers can learn some important lessons from successful programs that demonstrated the baseline design and economic upgrade concept such as the Lockheed C-130 Hercules aircraft. Although it is unlikely that the designers of the C-130 anticipated the current 54 configurations of this airframe, the basic modularity of the C-130 enables tremendous reconfigurability. The original concept of the C-130 was to provide a baseline heavy lift aircraft capable of transporting a variety of cargo. Over the years, operators and designers have found a host of uses for this plane-from U.S. Coast Guard Search and Rescue to U.S. Air Force gunship configurations. The C-130 has also gone through a series of upgrades over the years, incorporating advanced technologies that have increased its endurance, speed, payload and power. The success of this simple, spacious, affordable design is attested by the fact that over 2000 aircraft have been delivered to 63 countries around the world since 1954, and upgrades are still under way!
Breaking the Cycle
In order affordably to integrate advanced technologies into new submarines and test them at sea, the historic and lengthening cycle time to design and build submarines must be reduced. Currently, the cycle time to design and build a new submarine is approximately 12-14 years. The key to compressing this span is to reduce the activity level associated with changes to the design after construction has begun. Minimizing changes and their associated activity-through the incorporation of concurrent engineering and integrated product development-will simplify material procurement, reduce support and retest requirements, and improve labor productivity. However, it is naive to assume that, as construction progresses, changes to the design will not be required. Minor corrections or changes to the design will be incorporated in the particular submarine; major design changes will be incorporated into the design cycle for the next submarine. These major changes will typically be included in a major technology upgrade to the baseline platform.
Strategy for Success
NAS will provide the opportunity to demonstrate new afford-ability and multi mission concepts where it really counts-at sea. Submarine operators will supply feedback to the designers to improve the baseline design. Modifications to baseline submarines will be incorporated in subsequent construction units. These essentially one-of-a-kind submarines will be built at a rate to maintain the critical mass of the submarine industrial base. When serial production is required, proven technologies will be available for incorporation into a new class design.
This strategy alone will not assure an affordable Submarine Force. Cultures must be changed . Government and industry must join together and challenge all aspects of the submarine acquisition system. For example: ·
- Contractual procedures must be revised to reflect the Administration’s decision to build nuclear submarines in one nuclear shipyard, and aircraft carriers in the other.
- Traditional submarine performance criteria must be rigorously examined to reduce cost.
- The entire bureaucratic administrative process must be streamlined to eliminate unnecessary procedures and activities.
- The philosophies of concurrent engineering and integrated product development must be embraced and their principles reflected in the acquisition process.
These cultural changes, coupled with the philosophy of integrating new technologies into a baseline design, represent an affordable approach to maintaining the submarine industrial base into the next century.
