The Chief of Naval Operations, Admiral Mia Boorda, on 21 March 1996, asked Norman Polmar for his opinions on the concept of a submarine arsenal ship. The following is from Mr. Polmar’s memorandum to Admiral Boorda, dated 3 April 1996, which was made available to THE SUBMARINE REVIEW after Admiral Boorda ‘s death. Mr. Polmar served on the ARPA study panel that led to the current Navy-ARPA project for developing such an arsenal ship.
Memorandum for Admiral Boorda
Subject: Submarine Strike Ship (CSSGN)
Further to our discussion of modifying SSN 688s to an arsenal or strike ship configuration, I would submit the following:
l. Concept. The highly promising arsenal or strike ship project should consider the value of a submarine variant-in essence an underwater cruiser (CSSGN).
There appear to be six advantages in pursuing the CSSGN concept:
(1) stealth features of a nuclear-propelled submarine, i.e., low visibility-permitting unobserved deployment if desired-and high survivability.
(2) self-contained platform, requiring no escort or support functions from other ships.
(3) rapid response time O.e., high submerged SOA regardless of surface weather conditions).
(4) use of existing Loa Angeles (SSN 688) hulls that have 10+ years of service remaining.
(5) employ existing systems and technologies with high demonstrated reliability, i.e., low risk.
(6) provide additional work for both submarine construction yards (Electric Boat and Newport News Shipbuilding) and, if desired, a submarine overhaul yard (Portsmouth Naval Shipyard).
2. Proposal. The Navy should undertake an objective analysis of the CSSGN concept.
3. Background. The basis of the CSSGN concept is to insert a hull section containing Vertical Launching Systems (VLS) in an SSN 688 submarine. The concept of converting submarines to different roles through the insertion of major bull sections has been used by the U.S. Navy for more than a half-century.
For example, at the end of World War II several diesel-electric submarines were converted to the radar picket (SSR) role by the insertion of 30 foot hull sections and other changes. The best known U.S. submarine conversions were the construction of the SKIPJACK (SSN 58S) design with the addition of a 130 foot section to produce the first U.S. ballistic missile submarines of the GEORGE WASHINGTON (SSN 598) class. More recently, the attack submarine PARCHE (SSN 683) was converted in 1987- 1991 to a deep sea search/recovery submarine with the addition of a 100 foot section.
The Soviet-Russian Navy also made major modifications to nuclear-propelled submarines. For example, three of their early Polaris-type submarines of the Yankee (Project 667 A) class have been reconfigured as cruise missile submarines with a new, elongated midships section inserted. These submarines can each carry some 40 of the SS-N-21 land-attack missile, similar to the U.S. Tomahawk (the Russian designation is RKV-500 Granat).
The SSN 688 design is capable of accommodating the conversion because of its large size and powerful nuclear propulsion plant. For example, compared to the Skipjack design that was converted to the Polaris configuration, the SSN 688 has twice the shaft horsepower available.
From a technical viewpoint, the conversion of the SSN 688 to a cruise missile configuration would involve no technical risk; the only performance degradation would be the loss of a couple of knots in speed. (Note that the SSN 688 is the fastest U.S. submarine now in service with an underwater speed of 30+ knots.)
4. Discussion. The U.S. submarine community has proposed the conversion of some or all of the four Trident SSBNs that will be retired from the strategic role to an arsenal ship configuration. This proposal is not recommended because of the large size of the Trident submarines and hence higher conversion costs, the need to remove Trident fire control systems, etc.
Also, the relatively small support base for maintaining 10 to 14 Trident SSBNs after the year 2000 in comparison to the support base for some 40 (or more) SSN 6881 make it more efficient to support strike ships hued on the attack submarine.
The proposed CSSGN would consist of a basic SSN 688 submarine with the following modifications:
- reconfigure the front end of the SSN 688 to provide for 12 VLS (as in Improved SSN 688a)
- insert a midships section of approximately 100 feet fitted with approximately 100 to 120 VLS tubes
- provide appropriate fire control equipment
The SSN 688 would retain four torpedo tubes (amidships Mk 67), and full sonar and torpedo fire control capability. The current stowage of 20+ torpedoes, however, may be reduced in favor of additional Tomahawk missiles (torpedo tube launched) or some stowage space may have to be reconfigured for fire control equipment. (In addition, four torpedoes/missiles can be kept in the tubes.)
There would be few if any additional personnel required in the reconfiguration of an SSN 688 to the CSSGN role.
It is envisioned that the VLS sections (bow and amidships) would be fabricated at Electric Boat or Newport News Shipbuilding (both yards having built SSN 688s); installation could be undertaken at those yards or at the Portsmouth Naval Shipyard, which currently overhauls SSN 688s.