The Seawolf class was the last cold war fast attack submarines (SSN) design for the United States Navy, intended successor to the Los Angeles class. Design work began indeed began in 1983 and initially 29 were planned to be built over ten years. This was right at the start of the Reagan government. However rising program costs saw the initial batch reduced to 12, and after the end of the Cold War, further budget constraints led to the full cancellation of the program in 1995 and just three Seawolf-class built.

Spiralling costs of a model that was seen perhaps as over-ambitious led to design the smaller and cheaper Virginia class. At $3 billion in the 2000s per boat, the Seawolf class remains the most expensive USN attack submarine ever built. They were also subject of many changes, generating two sub-classes, USS Seawolf and Connecticut on one side, and on the other hand, USS Jimmy Carter which was “jumboised”. They found their place in the USN, being reconverted as “special purpose” submarines.
USS Seawolf (SSN-21) was built at General Dynamics Electric Boat, Groton, started 25 October 1989, launched 24 June 1995, comp. 19 July 1997.
USS Connecticut (SSN-22) was started at the same on 14 September 1992, launched 1 September 1997, comp. 11 December 1998.
Jimmy Carter (SSN-23) also, started 5 December 1998, launched 13 May 2004 and completed in 19 February 2005.
Initially classed as Cold War subs since their development program went back to 1983 with the lead boat was laid down in 1989, i decided to relocated them where they should belong, the modern days.

A Cold War Development

Early development

New advanced submarine, early concept in 1984 (not yet called seawolf), artist’s impression. src Polmar’s Ships and Aircraft of the US Fleet: 13th Edition

The early days of the Los Angeles replacement concept started well before the end of the cold war, back in 1982. At the time, the Reagan adminstration was just in place since January 20, 1981 and there were plans for a revival of the Navy after a decade of underfunding. The CIA knew full well about the latest, wome worrying development of USSR in submarines, starting with the Alfa class. On the other hand, Elmo Russell “Bud” Zumwalt Jr., admiral and CNO since April 1970 was butting heads with Admiral Hyman Rickover of the “sub faction” over his policy of “high-low mix” applied to ships that he wanted to apply also to submarines. That is a cheap type easy to built in wartime, close in concept to early conventional designs such as the 1950 Barracuda class.

Rickover, the ‘Father of the Nuclear Navy’, preferred buying a few major ships to buying many ordinary ones, a considerable difference in attitude privileging quality over quantity. However under Carter and Ford, post-Vietnam budget restrictions favored Zumwalt’s views. But in 1981, to reach the quantity of ships Reagan wanted, his planned relatively modular and large Spruance class destroyer, put also the basis for the future Ticonderoga class cruisers, as well as the Oliver Hazard Perry class Frigates. Zumwalt even milited for a 100+ strong class of Pegasus class missile hydrofoils. He retired from the Navy in 1974 at the same time of his post as CNO. His successor, Admiral James L. Holloway III (1974–2078) did little to start a new submarine program, the real deal happened under Admiral James D. Watkins, CNO under Reagan in 1982-1986. He was also a former submariner.

Many criticized the Los Angeles class as being slower than the Sturgeons, especially when compared to the latest Soviet submarines. A successor to the Los Angeles was thus studied from 1982, and according to Friedman, the “new advanced submarine” was much more toned down compared to what the USN (and especially Rickover’s faction) actually wanted. The first design showed a soviet-style sail, Y-plane arrangement for both the rudders and dive planes, and bow-mounted torpedo tubes with a conformal rather than spherical array, plus an automated torpedo reloading system to reduce the crew, as well as many other automation systems, recalling the concept behind the Alfa class. One rationale was to reduce costs, another to reduce size and weight, making the best of existing reactors to reach better speeds. However automation has a cost, and computers at the time were just not able to perform what was expected from them, that is automated target tracking and target motion analysis. Construction also called for the rather conservative HY-130 steel. Speed was not a factor as much as quietness to keep an edge on Soviet submarines, still very noisy.

Fat Albert

The F/A (variously Fast Attack, Fleet Attack, and “Fat Albert”) were much smaller alternatives, roughly 5,000 tons, low length to beam ratio, performance like a Sturgeon. This CNO Elmo Zumwalt late 1970s program was the equivalent of his surface high/low mix approach. The lower cost also authorize mass production in case of war. A return to some 1950s concepts.

AHPNAS

Rickover (the father of US nuclear sub program for those who don’t know) however savaged the program. His preferred alternative was the Advanced High-Performance Nuclear Attack Submarine (AHPNAS). More ambitious than a Seawolf it was twice the size of an Los Angeles and integrated a bank of vertical cruise missile launch tubes amidships, so in essence a SSGN. NASA also played its role shaping the hull of the Seawolf and its alternatives hulls, with trials made at the National Transonic Facility on Oct. 3, 1986.

The concept is approved (1982)

This new submarine had to operate under ice, hunting down the latest SSBNs, dive deeper, with strenghtened sail and retractable planes moved to the bow, the HY-130 enabled to achive this wiyhout weight penalty. The new planned towed array was to be a key asset in detection. The study was approved by secretary Lehman, funding studies FY1989 progral for 1.6 billion at 1 billion per ship from the 5th as planned. By December 1983, CNO Watkins approved the summary characteristics of the new submarine. At the same time, NAVSEA made a large enquiry of submariners about internal arrangements and general desired qualities for the new submarine. The first sketches showed the “soviet-style” boat concept showed above.

The new bow conformal array was called ACSAS and data was processes by a beam-forming computer and helped by extra slencing of the boat itself. The bow mounted planes again met heavy criticism from the USN. As the Y shaped tail for less resistance. The hull was defined as beamier but no longer than a Los Angeles, but with improved hydrodynamic performances. The new S6W reactor was to be lighter and more compact, yet more powerful. The pump-jet was agreed from the start, based on British experimentations. Again, this was a bold choice as it was considered less efficient than a traditional propeller, but compensated greatly by increased cavitation speed and removed blade-rate issues.

Design Modifications (1983-84)

The ambitious new sail, partly profiled from NASA studies, proved however too complex and the design went back to a more traditional sail, except a small wedge at its base which became the new design’s trademark. The sail was also much reduced in size, compact, compared to the Los Angeles and compared to the hull. Also, the Y tail reverted to a classic X one. The ambitious initial conformal array was undone by the computer’s capacity at the time, and instead, the torpedo tubes were moved to the hull’s sides, beyond the forward bulkhead (and now fully manned), while a spherical bow array was back in place, this time the BQS-6 that descended from the BQR-7 for a BSY-2 integrated system and SUBACS. The Y tail unit though survived through two stubs carrying two towed arrays, one TB-29, long ang thin, and the shorter, fatter TB-16E to give options.

Also, since computers of the time were just not able to simulate the complex water flow at all regimes to optimize water reistance and noise reduction it was decided to create a prototype hull, the miniature sub called LSV Kokanee. The results were encouraging as it matched or surpassed the Los Angeles hull for 2/3 of the intended displacement. At the time the program was called after the led boat, called SSN-21 to mark the fact it was to be the first “twenty-first century submarine”. However by 1983-84 as this proceeded, the Soviets were not idle either:

The challenge of 3rd gen Soviet subs

The Seawolf class were the result of concerns about the relevance of the Los Angeles class, a successful, but ageing design that went back to the mid-1960s, to counter the later advanced Soviet ballistic missile submarines such as the Typhoon class, or more recent attack submarines such as the Akula class in a deep-ocean environment. The latter in particular reached noise levels that were now comparable to western standards, and in 1983 the USN staff realized even the latter batch of the Los Angeles class, was not going to cut it. Indeed, a year before in 1982, Flight III, the last of the Los Angeles, was started, with a production from 1982 to 1989 of SSNs 751–773. They were a net improvement, already, called “688i” (for Improved, in reference to the lead boat SSN-688). They ought to be quieter, having an advanced BSY-1 sonar suite, and the ability to lay mines as well configured for under-ice operations.

New Soviet Titanium Subs

Yet, their hull was the same as SSN-688, enabling a diving capability of 450 m (1,480 ft), and it was judged not enough. The Soviet Navy tried to achieve greater depths, notably with the Alfa class in the 1960s at 400m tested, albeit many believed in the West they were capable of 700 and even 900 meters. The more recent prototype we saw K-278 Komsomolets of Project-685 Plavnik (NATO Mike) was also made in Titanium and believed capable of below 1,000 metres operational depths, in fact K-278 reached in August 1984 a record-beating 1,020m (3,350 feet). It should be said that the widespread Mark 46 acoustic torpedo with the Mod 5 launched in 1979 was unable to reach below 1,200 ft (370 m). The Sierra class (Project 945) on its own was also a powerful motivation for design. With their titanium hull they were also capable of diving below 550 meters (1,800 feet) if needed, and also could escape the Mark 46. In short, the Soviets were visibly on the path of out-diving and out-run US torpedoes in the 1980s, even if these subs were not the the majority. The Victors and Charlie were still the standard.

New Soviet Titanium Subs

In reaction, the Mark 50 Advanced Lightweight Torpedo was designed by the USN, instead of following the Soviet Union in titanium submarines construction, which seemed a daunting prospect. The Mark 50 torpedo was designed indeed as a 3th generation, advanced lightweight torpedo precisely for these very deep, very fast new soviet submarines. It was designed with the same versatilityy in mind, to be dropped by patrol aircraft, and surface torpedo tubes to replace the Mk 46. The key was sulfur hexafluoride gas sprayed over a block of solid lithium, as a heater to generate steam, and propulsion using a closed Rankine cycle to a pump-jet. There was a new resistant hull to boot and reach below 1500 meters of needed but also the combustion products occupied less volume than the reactants so no issues against increasing water pressure. But as it evolved, the program also targeted the Soviet submarines of the Typhoon class SSBN and new “standard” attack submarines of the Akula class and successors, keeping some margin of advance. Indeed the Akula boasted significantly reduced acoustic noise profiles due to advanced propeller technology acquired controversially (Toshiba precision machining tools).

As for submarines, the current arsenal of Mark 45 of the 1960s provided as standard to the Los Angeles was no longer sufficient and the USN worked a 3rd generation submarine torpedo as well in the 1970s, called the Mark 48. It too, was designed to combat fast, deep-diving nuclear submarines or high performance surface ships. In the 1980s it was superseded by the Mark-48 ADCAP (for ADvanced CAPabilities) dispensed to the Ohio class (SSBN-726) SSBN. The Mark 48 replaced the Mark 37 and antiquated Mark 14 in priority, but substantial stocks of Mark 45 remains for classic anti-surface hunting. The price of the mark 48 was also way above a Mark 45 so it remains an exceptional asset rather than the norm. The Mark 48 and Mark 48 ADCAP had optional wire guidance plus active/passive homing, and were autonomous, capable of multiple reattacks if they miss the target while being able to reach for the Mod 0 55 knots for 35,000 yards (32,000 m) and reach as deep as 2,500 feet (760 m) with an acoustic homing system having an acquisition range of 4,000 yards (3,640 m), four times that of the Mark 37. A pure gem as torpedoes went, but a very costly one indeed at $4 million dollars apiece for a MK-48 ADCAP MOD 7.

SUBACS Program

The SUBACS (Submarine Advanced Combat System) program. In the November 1985 report NAVY ACQUISITION: SUBACS Problems may Adversely Affect Navy Attack Submarine Programs to Congress, is as follows:

We recently reviewed the Navy’s three-phased Submarine Advanced Combat System (SUBACS) program. SUBACS was designed to provide Los Angeles class nuclear attack submarines (SSN 688 class) authorized for fiscal year 1983 and beyond with new and upgraded sonar and combat control systems and advanced data processing capabilities. A modification of SUBACS was also planned as the combat system design for the proposed new attack submarine class, SSN 21, scheduled for authorization in fiscal year 1989. We performed this review to determine the cost, schedule, and performance risks associated with implementing the SLJBACSprogram and its impact on attack submarine programs.

We found that since the Secretary of Defense approved the program in October 1983, SUBACS has experienced significant cost, schedule, and performance problems. To address these problems, the Navy has made several programmatic decisions, resulting in a restructure of the program. As a result, the program is no longer being implemented as approved. Because of the risks and uncertainties identified with implementing the latest program plan, we believe that the restructured program needs to be evaluated and implemented only with the approval of the Secretary of Defense.

On October 25, 1985, the Department of Defense provided comments on a draft of this report which have been incorporated in this final report. The Defense-Approved The Navy initiated SUBACS in 1980 to meet expanded SSN 688 class mis SUBACS Program sions and to counter the Soviet antisubmarine warfare threat through the 1990s. SUBACS was originally planned as a single-phase program for SSN 688 class submarines authorized in fiscal year 1989. However, in October 1983, the Secretary of Defense approved the Navy’s plan to introduce SUBACS as a Pre-Planned Product Improvement1 program in
three phases.

SUBACS Basic, the first phase, was to upgrade existing sonars, add new sonar subsystems, and provide for processing of acoustic information by a distributed system data bus2 It was scheduled to be installed on the SSN 688 class submarines authorized in fiscal years 1983, 1984, and 1985. The nine SuBA equipped submarines authorized in those fiscal years are currently under construction by two shipbuilders. Five are under construction at the Electric Boat Division of General Dynamics Corporation and four are under construction at Newport News Shipbuilding Company. SUBACSA, the second phase, was to integrate acoustic and combat control processing by using new and upgraded software. SWAGSA was for SSN 688 class submarines scheduled to be authorized in fiscal years 1986 through 1988.

SUBACS B, the third phase, was to introduce sonar improvements into the integrated combat system. This phase was for SSN 688 class submarines scheduled to be authorized in fiscal year 1989 and beyond. A modification of SUBACSwas also the combat system design for the proposed new attack submarine class, SSN 21 (The Seawolf class). This LA Batch III and Seawolf common program was to gain time and save money and ended all the contrary.

See the full report here. In short, SUBACS was decounced as “having experienced significant cost, schedule, and technical performance problems”. This was blamed on the navy decision of:
1 introduce innovative technology into new construction attack submarines through a concurrent development and production program
2 install the initial SUBACS on a FY1983 submarine rather than on one scheduled for authorization in FY 1989 (Seawlf class), as originally planned
3 approve the shipbuilder’s accelerated delivery schedules for initial SuBACS-equipped submarines.

It was concluded these decisions for the program success became highly dependent upon receiving sufficient funding, maintaining tight cost control, and meeting crucial schedule dates in each of the phases. By April 1983, a Naval Material Command audit indicated the SUBACS Basic phase would cost $762 million, $105 million more than the Navy’s initial estimate. By FY1985 $853 million more in R&D Test and Evaluation funding. Seems familiar ? This was not in the 2010s but the 1980s… It’s deep long term effect was the cancellation of the Seawolf program, in addition to the end of the cold war.

Alternative: The Centurion Program

Surprisingly enough, the Seawolf class was not the only successor to the Los Angeles studied from 1982. The low-range alternative to the Seawolfs were originally called the “Centurion” and the initial program later became the Virginia class, considered at the time planning for the SSN-21 class, but reconsidered due to cost. More on the 15th edition of the Naval Institute Guide to the Ships and Aircraft of the US Fleet.

SSN-21 Program meets the end of the cold war

Whatever the choices made, in 1984 it was generally believed this 3th generation SSN needed to happen of the US would lost its acoustic advantage. In 1984 the SSN-21 program was named “seawolf” to remind the sescond SSN after USS nautilus back in the 1950s, which was so instrumental to go from a nuclear experiment to a proper military submarine. It was also because since Nautilus, development was to stretch the life of the reactor, so to reduce the life cycle cost of the submarine. A one-shot reactor was the main challenge they had to face, but it was part of the package for the Seawolf class. It would be worth on the long run it even when paying a greater cost up front. The Congress was perhaps more impressed by the concept than all other perks of the new submarine and approved extra funding for 1986, 1987 and 1988. The new submarine was bought as FY 1989 arrived, and two more FY 1991. Thirty Seawolf class SSNs were planned, with two built every year up to the 2010s.

But in 1990 the USSR collapsed. This changed everything. Suddenly the Seawolf class appeared as specialized cold war relics. Degence cuts was the immedate follow-up and the Seawolf class appeared as a costly program to face basically the rapidely collapsing submarine fleet of a former adversary now having an uncertain attitude but no budget either. As the years went, it was clear that the Soviet immense submarine park was now stranded and rusting. Without adversary it was just impossible to maintain the Seawolf program as it was and it was terminated by Richard Cheney in 1992. However the Congress asked to maintain expertise in submarine construction so the two FY 1991 boats were confirmed, after a suspension, which was accepted by Cheney. The third boat was conformed again by Clinton during the presidential elections to keep Electric Boat busy. On the other hand, the Los Angeles class would simply be continued for the same reasons.

Los Angeles Flight III

USS Cheyenne, SSN-773, last Flight III (commissioned 1996)
The Flight III or 688i (Improved) was a sub-class, the last, of the Los Angeles class nuclear attack submarines, the last “classic” SSNs derived from the early 1960 Sturgeon. The lead boat was USS San Juan (SSN-751) laid down at General Dynamics (Electric Boat) in Groton in November 1982. It was part of an order for 23 Flight III, no more ere ordered as the cold war ended and a replacement type was on its way. The very last was USS Cheyenne, SSN-773, laid down in November 1989 and completed in 1996. Apart two, all Flight III are still active today.

The Flight III adopted the innovation brought by the Flight II boats, 12 new vertical launch tubes firing the Tomahawk missiles so these last 23 were SSGNs, but benefited of a significant upgrade, made much quieter (level classified), with more advanced electronics as well as new sensors, and other noise-reduction technology, in and out, plus some active cancelling systems. The diving planes were also relocated at the bow rather than on the sail, made retractable. A further four were proposed by the Navy but cancelled as the cold war ended. These were also and “insurance” as the new SSN-X program went on, in case of delays. The latter started at the same time the Flight III were initiated, and it was believed delays in its development would be compensated by the construction of extra Los Angeles, notably to keep the shipyard’s workers and their precious associated skills.

Building the Seawolf: A new Steel

Seawolf-class hulls are constructed from HY-100 steel, the second part of the solution. This was studied as an alternative to titanium, and was more alloy than reinforced or special steel. It is stronger than the HY-80 steel of previous classes and capable of withstanding water pressure at much greater depths. Its Tensile Strength, Ultimate was between 792–930 MPa in metric, or 115 – 135 ksi in imperial measures and its Tensile Strength, Yield was 690–897 MPa and 100–120 ksi with an elongation of 18 so even more flexible to withstand a gruelling cycle of deeper dives and rapid surfacing many times during the long life cycle of the submarine. Each dive was indeed a great stress on the pressure hull. The outer hull did not change much however and remained thin, albeit reinfirced somewhat at the bow.

Outside the pressure hull, the rest of the submarine was to be also redesigned to integrate new materials:

March 1986: SUBMITTED BY DEPT. ABARIS NAVY, 125 CATRON DR RENO, NV 89512. CONTRACT NUMBER: WILLIAM L MURPHY. ASSESSMENT OF FIBER REINFORCED PLASTICS FOR COMBATANT SUBMARINE STRUCTURES
TOPIC# 50 OFFICE: NAVSEA
THE PRESSURE HULL OF A COMBATANT SUBMARINE WOULD BENEFIT FROM THE CHARACTERISTICS OF COMPOSITES, AND THUS IS A GOOD CANDIDATE FOR THE APPLICATION OF THESE MATERIALS. THE TWO CANDIDATE MATERIAL SYSTEMS. ARE THERMOSETS AND THERMOPLASTICS. THE PROJECT IS TO CONDUCT PRELIMINARY DESIGN STUDIES OF THE PRIMARY HULL STRUCTURE, FRAMES, JOINTS, PENETRATIONS, AND ATTACHMENTS USING GRAPHITE FIBERS AND
POLYETHERETHERKETON (PEEK) RESIN. DESIGNS WILL BE ANALYZED FOR STRUCTURAL PERFORMANCE. A SCALE CANDIDATE HULL SECTION WILL BE SELECTED, A DETAIL DESIGN CONDUCTED, AND TEST HULL SCALE SECTIONS WILL BE BUILT.
A TEST PLAN WILL BE DEVELOPED, AND A TEST FIXTURE BUILT AND INSTRUMENTED. TESTS WILL BE CONDUCTED AND RESULTS DOCUMENTED. PLAN FOR THE WORK OF A DEMONSTRATION AND VALIDATION PHASE LEADING TO A MILESTONE II AND FULL SCALE ENGINEERING DEVELOPMENT IS OFFERED AS AN OPTIONAL TASK.

So we can guess composites were used in large quantities both for someparts of the outer hull with theior a-magnetic properties and internal arrangement as well, now to avoid both magnetic signature, structural noise when in contact with the pressure hull, and buffetting of all human and mechanical noises in general.

The most badass US submarine ever

While studied in the 1980s with a new steel and new torpedo coming from different departments and companies, the USN always wanted the Seawolf-class to be faster and significantly quieter as well than previous Los Angeles-class submarines and to carry more weapons with twice as many torpedo tubes, even if this means having a larger boat overall. One armament planned from the start was the new UGM-109 Tomahawk cruise missile for covert strike missions, and the SSN-21 were designed to carry up to 50 of them to deal with land and sea surface targets. That was indeed unprecedented. They were also designed with the more extensive equipment possible for shallow water operations. In short, they were to integrate natively all the bells and whistles provided to specialized versions of previous submarines in these field.

Another major new asset was the more advanced ARCI Modified AN/BSY-2 combat system including a larger spherical sonar array in the bow with a wide aperture array (WAA), and new towed-array sonar, longer and several more resecptive at very large distance passively. Propulsion-wise they needed to be fitted with a new generation reactor, the single S6W nuclear reactor, still a classic PWR (presurized water reactor) able to deliver 45,000 hp (34 MW), with extra silencing measures taken, coupled to a low-noise pump-jet to further reduce noise. That sum of novelties in design rapidly reched a staggering global cost even without adding the total R&D: The projected cost for 12 submarines in 1987 when the program was practically complete for this class was $33.6 billion. As the Cold War ended however, the axe fell. Two were completed, a third was suspended, completely redesigned, and became its own class. This was the start of a long serie of one-offes and limited, very costly series in the post-cold war (now unfortunately inter cold war) era.

Design of the class

Hull and general design

HY-100 steel

The stress strain behaviour of HY-100 steel. The number arrows indicate nominal strain (research gate)

The HY-100 as said above was a game changer. It was designed and manufactired by Broken Hill Proprietary Steel International, Slab and Plate Products Division and heat treated by Bunge Industrial Steels Pty Ltd. It satisfied the requirements laid down by US Naval Sea Systems Command for first article qualification (Military Specification MIL-S-16216J (SH)) following a procedure in which explosion bulge testing is waived, but where HY-80 steel from the same source is already qualified under NAVSEA approval. The baseline was a 690 MPa yield strength over a 50.8 mm (1.96 in) thick plate. This gives an idea of the full thickness of the submarine hull. To put thing in perspective it is ten times thinner than an Iowa class turret faces, reaching back in 1940 19.5 inches or 495 mm. The final thickness for construction was established at 2-inches or 51 mm, close to the sample tested, albeit the true thickness might be classified. The latter is from open sources.
The outer hull remains around 0.5 inches, the exact figure is difficult to find. In any case, the HY-100 steel is reputedly 20 percent stronger than the HY-80. This enabled dives in theories 20% below that of a Los Angeles, so officially 800 feet (244 meters) compared to 650 feet. Construction relied on a new welding material to join the steel into plates, hull subsections and large cylindrical sections.

Larger Dimensions

For the first time, a SSN became larger than earlier SSBNs: The new Seawolf class was estimated when constructed in its final form as having a surfaced displacement of 8,600 tons and submerged displacement of 9,138 tons. For the later redesigned USS Jimmy Carter this even reached 12,139 tons full. To compare a Lafayette class SSBN was 7,310 tons/8,260 tons. They were 353 ft (108 m) long (again 452.8 ft (138.0 m) for USS Jimmy Carter) for a beam of 40 ft (12 m) versus 360 ft (109.8 m) long, 33 ft (10.01 m) wide (disp. 6,900 tons) for a Los Angeles Batch III. So despite being much heavier (partly due to the new stell) they ended not longer than their predecessor but 7 ft wider (2 meters) which made a massive difference in internal arrangements. Part was taken by a larger ballast area, to dive deeper, making the pressure hull only moderately larger (exact beam unknown so far in open sources).

Powerplant

Propulsion of this beamier submarine relies on a single, larger S6W PWR rated for 220 MW (300,000 hp) with an HEU of 93.5%. To compare, a Los Angeles class has a S6G nuclear reactor only capable of 165 MW in the Batch III, and its steam turbines produced 33,500 shp, whereas a Seawolf class had a secondary propulsion submerged motor and its two steam turbines were rated for 57,000 shp (43 MW) total combined, also on a single shaft. The great novelty was their pump-jet propeller installed from the start to reduce noise. The Seawolf ended twice as powerful, due to a heavier hull and the need for better speeds. Still, its silent speed was about the same, at 20 knots (23 mph; 37 km/h) and a max speed to escape potential attacks at 35 knots (40 mph; 65 km/h). It was 33 knots reported for a Los Angeles, but 25 kts official. The exact speed of a Seawolf is classified, 35 kts is the official figure. Some analysts estimated it could be as fast as 38 knots. They could also reache as seen above a greater test depth of 1,600 ft (490 m), with a considerable margin for the theoretical crush depth, twice as much. Range is of course, being nuclear-powered, unlimited.

Crew and internal arrangements

The endurance is down to the human factor, and only limited by food supplies. The more generous pressure hull enabled extra food to be carried (measure unknown) for a crew of 132 up to 140, compared to 129 for a Los Angeles. It’s a paradox as this new generation SSN was supposed to be greatly automated compared to the 1970s Los Angeles (30 years of automation advances) but the explanation is rather simple: More systems, more weaponry, and everything more advanced. The new combat control room for example has twice as much operators compared to a Los Angeles class, and in theory the Seawolf class could be compared as “command submarines” even if it’s not their official role, nor designation. The extra space up to 140 berthing space is for exceptional guests and VIPs.

Overall globally, internal arrangements follows the overall design of the Los Angeles in principle, but there were many changes. The design conception of the Seawolf class for the first time called for advanced computer modelling, still in its infancy back in the late 1980s. The new Columbia/Virginia however were partly designed using virtual reality and a more dynamic process. The S6W reactor is a naval reactor had its designation stands for S, Submarine platform, 6, Sixth generation core designed by the contractor and W, Westinghouse was the contracted designer. This pressurized water reactor was prototyped in the land-based S8G plant at Knolls Atomic Power Laboratory’s Kesselring Site in West Milton, NY starting in March 1994. The three ships of the Seawolf-class submarine USS Seawolf (SSN-21), USS Connecticut (SSN-22), and USS Jimmy Carter (SSN-23) were the only ones using the S6W reactors ever. It had a thermal power output of 220 MW (300,000 hp) and a shaft power output of 43 MW (57,000 shp) through 2 steam turbines. It is believed to be able to utilize natural circulation at a large fraction of its full power without coolant pumps, greatly reducing noise.

Silencing Measures

A New Hull Shape

In addition to the natural circulation, which exact details are of course classifed, the Seawolf class depended on many other technologies. As seen above, hydrodynamic studies with the LSV Kokanee preceded by NASA studies allowed to alleviate computer limitations to calculate the ideal shape. The hull was indeed much beamier than a Los Angeles, but the nose curve and long sloped tail both were more optimized for better water ciculation, water scoops shapes and location were also refined, and of course, the new sail was boith a bit smaller than the Los Angeles, was plane-less, since they were now retractable in the bow, and had a small “transition” at its feet to improved also seaworthiness as the sail’s base, the point where it meets the hull, always was a “trap” causing a lot of turbulences underwater. This was definitivey the aspect that most stands out. This aspect was passed onto next generation SSNs and SSBNs as well.

Outer Hull Anechoic Paint and Tiles

As for the outer hull, it was coated by a sonar-absorbent paint AND had anechoic tiles system developed both by the Soviet and British subs. It was still designed to absorb and scatter sonar signals, and this rubber-based acoustic tiles were designed to both outer absorb active sonar pulses and dampen internal noise radiated from the submarine to reduce detectability. Paint was secondary, used over or around the tiles, and on areas where tiles are impractical like edges, fittings, and some control surfaces. The paint provides corrosion protection, hydrodynamic smoothness, and antifouling, but not significant acoustic stealth. The cladding seemed to have been more extensive than earlier Los Angeles–class boats, not only due to the larger hull, so more area to cover, but also by making the tiles smaller, thus avoiding water turbulences in case of peeling off. Rare close ups of the Seawolf shows integration work for these numerous, small tiles was a work of art.
The Los Angeles class in comparison had fewer and earlier-generation tiles. The Virginia class was also heavily tiled, but with newer materials and modular construction.

Inner Hull Rafting

Back to the engine room, the other elephant in the room was the suspension of the new S6W nuclear powerplant, but also all transmission systems and in general anything that could produce vibration at any level. The “rafting” scheme is of course ultra confidential and classified, but in essence, improved compared to the Los Angeles, notably thanks to a much beamier hull, enabling more space between the outer and pressure hull AND inside the pressure hull’s own walls. The thicker HY-100 was to play a role in that, by working on steel resonance compared to all attachement points to the decks. Cancelling any resonance was paramount. It is likely also progress was made in the opening and closing of the forward side torpedo tube doors to avoid a rush in water or any radiating mechanical noise.

Pump Jet

There was also the pump jet: Its noise-reducing qualities are well know, and the Seawolf class ditched the previous bronze 7-bladed hooked propeller design for an inside combo of a longer propeller cowl and shorter one with a succession of a stator and rotor blades, then a new set of blades ina three stage arrangement. The 8-bladed free stator, then 6-bladed fixed ring propeller and 8-bladed end cone were designed to break any possible water turbulence emitted by the propeller’s blades, all hooked to some degree and at some different angles (potentially contrarotative). This was all computer calculated as the ships were in contruction. It seems also the latter Jimmy Carter had a modified pump jet propulsor design, still classified. There are some models around based on rare photos that shows some clued by all real photos of the boat in construction or refit had a tarp covering the pump jet rear opening, making all the rest pure speculation. But this made the Seawolf class a pioneer in this tech, repeated and improved upon for the next Virginia/Columbia.

Active Noise Reduction (ANR)

As for any active noise reduction system (ANR), there is only speculations as well. Active noise cvancellation systems for submarines are used since the cold war old Prairie Masker. One trick was for example to emit bubbles along the facing side of the blades. Ships also used various noise cancellation systems. But for the late Los Angeles and Seawolf, this is all of course highly classied. Water transmits sound extremely well and noise sources are distributed (machinery, flow, structure) so cancellation must work over multiple frequencies and directions and used only in very specific, controlled contexts.

The base method is that sensors (accelerometers) detect vibrations from machinery and actuators apply counter-forces. Here is a list of systems on which these cancellation measures applies: The Turbines and reduction gears if present with ultra precision machining, the residual Pumps and HVAC systems (natural circulation unconfirmed, yet very likely). The end result works at low frequencies where passive mounts are less effective. Interesting active measures could be expected on active raft mounts (cancellation of any nascent vibration by a counter-vibration at low harmonics level), active magnetic or hydraulic isolation systems and in general, an active control of internal acoustic fields to reduce not only crew fatigue but also internal resonance on the hull mass coupling sub all-sub-elements, using sets of microphones + speakers in confined compartments and using narrow-band cancellation on specific frequencies. Active noise reduction of hull radiation is however extremely complex and works only over limited frequency bands, must be used selectively.

The end result of all this makes the Seawolf allegedly ten times quieter over the full range of operating speeds than the improved Los Angeles and even seventy times quieter than the original Los Angeles class, running quiet at twice the speed of previous boats. This made it still much quieter than the Akulas and their successors presumably, even quieter albeit this is disputed, than European nuclear subs of the last generation.

Protection

This chapter concerns the survival of the submarine in operation, as well as internal material protection systems and survival of the crew.

Underwater Decoys

Another classified, albeit better known topic. Based on small torpedo-like sytems for their body and working for a short time, less complex as they are consumables, they are still infintely more costly and complex than air-burst surface decoys, that are glorified rockets. The base principle is that they have to confuse or seduce torpedoes, break sonar lock, create false targets and in the end, buy time to maneuver or escape. Legacy systems such as the ADC/AN/SLQ-25-derived decoys are simple acoustic noise generators mimicking broadband submarine signatures, and they were replaced by new systems which are right now classified. These are modern Expendable Mobile Decoys which in public sources are confirmed to be smaller, smarter expendable decoys compared to these legacy systems (and common to the Batch III Los Angeles and Seawolf, Virginia/Columbia). They could be launched depending on the type from countermeasure launchers built in teh hull or sometimes torpedo tubes and has programmable acoustic profiles, time-varying signatures but still limited mobility or drift control.

Countering a torpedo with another torpedo is another chapter altogether but another active protection form. Torpedo-intercepting torpedoes (hard-kill) or underwater interception is extremely difficult to perform, whereras a soft-kill works against a wider range of threats at a lower cost and risk. The base issue is the very short notice before a torpedo is detected before the kill. The interception must occur in a goldilock zone before the detonation wave could be harmful for the submarine, about 500 meters from the ship, still about 24 seconds till impact. Isareli company Rafael for example markets its Torbuster system which is a combo of hard-kill/soft-kill as a clue of what the USN uses currently and was impossible back in 1995. In any cases, Mk46/50/54 lightweight torpedoes are a good contender as interceptors, less costly than a Mark 48 for that job.

Pop Mech 1998 issue, cutaway showcasing the Seawolf src. Note the odd 12-bladed propeller…

Internal Safety

NBC protection is not an issue for a submarine unless it’s using its emergency snorkel mast. In that case it’s likely joint with a NBC detector. As for fire protection it is the result of a combination:
-Sprinklers with automatic detectors in the most critical areas (CC, galley, batteries, armament bay, engine compartment)
-Easily accessible halon fire extinguishers for the crew at regular intervals
-Hoses and water pumps in various area locations
-Trained crews in fire protection (often crews with dual roles)
-Fire-resitant materials, doubling or with also noise-cancelling properties.

Saving the Crew

Like any former submarine, crew-saving measures starts with the boat itself and its well known eight compartments bulkheads. The outer ones has hemispheric shaped ulkheads tobetter resist pressure at both ends of the internal hull, starting from just behind the bow spheric array (submerged) and ending short of the shaft base in the tail. Heavy, flat-face bulkheads are then located in the pressure hull but sub-divided into a forward and rear areas and in,termediate stronger bulkhead aft of the sail.

The other is of course the two external sas systems, with clear markings over the black hull paint over the riles, one aft of the sail, at the very end of the forward main survival area and another aft, about mid-ship of the aft engine compartment. Both are designed for a DSRV rescue submarine to fit and save as many men as possible. But given the depths in which the Seawolf operates, there are few alternative for individual survival, but using the same systems to escape, one man after another equipped with a breething apparatus. Training is procured to use this system, but the price to pay, if it’s survivable at all, is an internal ears burst and other pressure-related damage.

Armament

The Seawolf had twice as many torpedo tubes with a 30% increase in magazine size coppared to the Los Angeles-class in order to establishi and maintain “battlespace dominance”. Their greater stealth is also an asset for special operations, using combat swimmers into denied areas. But the great novelty of the Seawolf design was its array of eight side torpedo tubes. As the previous Los Angeles class, the need for a spherical array had the tubes relocated to the forward sides of the hull inside the bulkheaded forward compartment, behind the sonar and forward ballast compartments. The advantage was to enable a larger weapons room, and more space for manual handling. The initial idea of a fully, remotelly automated weapons room was dropped as seen above, so the Seawolf ended with a larger crew. The other iinitial idea of vertical launch tubes (VLS) for cruise missiles was also dropped due to design complications, albeit it was done for the Los Angeles class Flight II/III.

Instead, engineers proposed a new idea, provided the weapons room was taller: Using instead 26.5-inch (760 mm) torpedo tubes, sleeved for 21-inch (533 mm) weapons. This enabled larger diameter encapuslated missile, in that case the large BGM-109 Tomahawk, which base diameter is compatible with previous tubes (20.4 in (0.52 m)) however not inside their full encapsulated canister. This also gave some margin for future larger weapons.

UGM-109 Tomahawk

The Seawolf likely after commission were tested to operate the BGM-109C Tomahawk Land Attack Missile. It has a conventional warhead (TLAM-C Block II), the WDU-25/B unitary warhead, 992 pounds (450 kg) filled with 378 pounds (171 kg) of Picratol plus H-6 HI mix. From May 1993, the WDU-25/B warhead was replaced by the lighter WDU-36/B warhead of 690 pounds (310 kg) with 265 pounds (120 kg) of PBXN-107 HE, more effective. The smaller warhead allowed for a larger fuel tank and better range as the TLAM-C Block III.

---

Mass: 2,900 lb (1,300 kg), 3,500 lb (1,600 kg) with booster.
Dimensions: 18 ft 3 in (5.56 m) without/20 ft 6 in (6.25 m) with booster, diameter 20.4 in (0.52 m), wingspan 8 ft 9 in (2.67 m)
Warhead: WDU-36/B 690 pounds unitary, see above. The BGM-109D could use a submunitions Bomblets dispenser to target tanks concentrations or airfields.
Detonation mechanism: FMU-148 since TLAM Block III.

UGM-84A Harpoon

The Seawolf class also operates likely the encapsulated Harpoon Block 1D anti-ship missile. This version has a larger fuel tank, re-attack capability by searching in a clover-leaf pattern. This late cold war model had its manufacturing cust short after the fall of the Soviet Union. Range 150 miles (240 km), other designation U/RGM-84F.
The Seawolf were likely later upgraded with the SLAM-ER (Block 1H) which entered service in 1999, also with re-attack capability, image comparison capability for autonomous priorities during the terminal phase target acquisition and lock on. Redesignated UGM-84H (2000-2002) and later UGM-84K (2002 onwards).

---

Mass: 1,523 lb (691 kg) including booster for 15 ft (4.6 m)x 13.5 in (34 cm), wp 3 ft (0.91 m)
Warhead 488 pounds (221 kg). Impact fuze.
Engine: Teledyne CAE J402 turbojet/solid propellant booster 600 lbf (2,700 N) thrust
Operational range Greater than 67 nmi (124 km) Block II, Sea-skimming
Maximum speed: 537 mph (864 km/h; 240 m/s; Mach 0.71) Block II
Guidance system: Monitored by radar altimeter, active radar terminal homing.

Mark 48 ADCAP

The Mk-48 Mod 5 (ADCAP) was extensively tested with a production starting in 1985, operational in 1988. Upgrades follwoed as in 2012 the Mod 6 entered service, a Mod 7 tested in 2008. By 2017 Lockheed’s production was 50 per year.

---

Mass: 3,695 lb (1,676 kg)
Length 19 ft (5.8 m), diameter 21 in (530 mm).
Effective range 24 mi (38 km; 21 nmi) at 55 knots (102 km/h; 63 mph) or 31 mi (50 km; 27 nmi) at 40 kn (74 km/h; 46 mph)
Warhead HE+ unused fuel 647 lb (293 kg), proximity fuze
Engine: Swash-plate piston engine Otto fuel II +pump jet
Maxi depth 500 fathoms/800 m (2,600 ft) est.
Guidance: common Broadband Advanced Sonar System

Sensors

AN/BSY-2 combat system

The AN/BSY-2 Submarine Combat System developed from 1986 after the cancelled 1981 Submarine Advanced Combat System program, was designed for the SSN 21 class to enhance combat operations, like a submarine verison of the shi-based AEGIS, to track multiple targets, manage in real time platforms, and weapons with a subsystem providing setting and control of weapons and mines, targeting, and all combat systems management while corrinating navigation. The CC houses a vertical large screen display, and mutiple stations and data displays for up to 20 operators.

The BSY-2, operational by March 1988 combines data from sonar tracking, monitoring, launch of all weapons, Mk 48 ADCAP, Tomahawk, Harpoons and mines. Key assets includes:
-The hull-mounted Wide Aperture Array (WAA) for rapid localization of targets (92-processor flexible architecture FLEXNET using fiber-optic
-The fully integrated Interactive Electronic Technical Manual (IETM) for on-board/shore-based maintenance, operations, and training.
However this program had issue resulting in late delivery and increased cost, in two phases bewteen the hardware and software, still partial operation by November 1993 until late 1994. Final delivery was from July 1995, second phase in October 1996. Since the,, Block 2 and Block 3 system upgrades had been implemented for better integration with the CCS MK2. The system was initially tested on Seawolf by the summer 1996, delivered the next summer 1997. The third system was installed on Jimmy Carter (SSN-23) with modificatons to better integrate spec-ops operations.

Spherical bow array

This system is part of the AN/BSY-2 combat system, containing thousands of hydrophones (underwater microphones) to detect, track, and classify undersea targets like enemy submarines and torpedoes. Its spherical shape maximizes directional sensitivity in all directions (360° coverage) to passively detect sounds underwater with extreme precision, with active and passive sonar arrays hundreds of hydrophone elements. Image

⚙ Seawolf specifications
Displacement	8,600 tons surfaced, 9,138 tons submerged
Dimensions	353 ft x 40 ft (108 x 12 m)
Propulsion	S6W PWR 220 MW (300,000 hp), 2 steam turbines 57,000 shp, pump-jet prop.
Speed	20 knots (23 mph; 37 km/h) silent or 35 knots (40 mph; 65 km/h)
Range	Unlimited, 60 days food supply
Test Depth	1,600 ft (490 m)
Armament	8× 26.5-in TTs: 50 weapons: Tomahawk/Harpoon/Mk 48 ASCAP
Protection	See notes: Decoys, EW
Sensors	See notes
Crew	140 max, 14 officers; 126 enlisted

Career of the Seawolf class

USS Seawolf was laid down on 25 October 1989, launched on 24 June 1995 and commissioned on 19 July 1997 at Electric Boat Division of General Dynamics. Contract was awarded on 9 January 1989. Her keel was laid down as the Berlin wall was about to fell and she was launched well after the end of the cold war and gulf war, sponsored by Mrs. Margaret Dalton. After her commission two years later in July, her construction time of 7-year 9-month broke the record for any submarine in the U.S. Navy, testifying of the utter complexity of the whole project, yet still, it was not that long. To compare, a Flight III Los Angeles like USS Cheyenne, took also seven years, from November 1989 to commission in September 1996.

She started sea trials with her EB yard’s support personnel and her partly rookie crew of 140 personnel. This was the largest crew for any SSN so far, only equivalent to SSBNs. In 1998, as she proceeded with her shakedown cruise, she was featured in an episode of the documentary “Super Structures of the World” following both her construction and sea trials. For this initil phase, in fact between 1995 and 1997, her crew and base personal received the Secretary of the Navy Letter of Commendation.

Her deployments from the east coast remains classified to this day, so details are lacking albeit they were some sticking points. She also routinely operated from New London base and possibly from the forward base in Scotland in Holy Loch. In 2001 she won her first Battle Efficiency “E” Ribbon. In 2002 she was deployed for the first time in the Middle East, and was awarded years later the Global War on Terrorism Expeditionary Medal for her global campaign 2002–2011. In 2004 she won a second Battle Efficiency “E” Ribbon.

On 22 July 2007, she was transferred from her normal homeport at the Naval Submarine Base New London in Groton, not far from Electric Boat, to Naval Base Kitsap, Washington, Westy Coat, reflecting on a change of policy towards the east and in particular the rapid rise of Chinese naval ambitions. She made her first WestPac (Western Pacific Deployment) and probable covert missions, earning that year a first record of awards, with Tactical White “T”, a third Battle Efficiency “E” Ribbon, the Marjorie Sterrett Battleship Fund Award for excellence in combat drills (highest score in the fleet’s annual competitions for Battle Effectiveness Awards) and a second Meritorious Unit Commendation for that campaign.

In 2009 for this year’s WestPac she won a second Navy Unit Commendation. Nothign of note for 2010-2013 but probably a major overhaul. In 2014 she made another marking WestPac, earning the Battle Efficiency “E” Ribbon, the Weapons “W”, Navigation Red and Green “N”, Supply Blue “E” and Personnel “P” awards. In 2015, she was deployed to the Arctic for six months, her first major deployment under the ice. For this campaign she won the Battle Efficiency “E” Ribbon, second Weapons “W”, Navigation Red and Green “N”, Supply Blue “E” and a first Engineering Red “E” award. Nothing of note for 2016-2019 (likely another refit).

In July 2020 Seawolf made a second Arctic campaign, and concluded a cycle of special operations, transiting to the Artlantic and visiting multiple European ports such as HMNB Clyde in Faslane (Scotland), Gibraltar, and Tromsø (Norway), and that year was partucular as this the was the first US Navy deployment during the coronavirus pandemic. That year was also the most fruvtuous so far i terms of awards, with yet another Battle Efficiency “E”, a third Weapons “W”, third Navigation Red and Green “N”, third Supply Blue “E”, a second Navy Expeditionary Medal, first Arctic Service Ribbon as well as the Navy and Marine Corps Sea Service Deployment Ribbon, a third Navy Meritorious Unit Commendation and a first Arleigh Burke Trophy, which is presented annually by sraff to the squadron demonstrating the greatest improvement in battle efficiency from the previous year, West Coast. This was a crowning achievement for her and her sisters.

As for 2022-2025, she made another 7-month WestPac making her first arrival at the brand new Olympic pier, inaugurated at the Naval Base Kitsap-Bangor on December 14, 2022. In April 12, 2023 she departed Kitsap-Bangor, stopped off Naval Base Point Loma for personnel transfer, Mike Pier in April 20-24 and May 4-6 and back home on May 11. On the 16th, Cmdr. Douglas G. Hagenbuch relieved Cmdr. Jeffrey C. Fassbender as CO and she departed on the 22 via Dungeness Spit for personnel transfer. She made a brief 2.5 month deployment and was back on August 5, at Olympic Pier Kitsap-Bangor for the 3rd and 7th Fleet Aera of Operations (AoR). She had a maintenance availability period in between, in June-July.

She was in Japan in September-October notably taking part in Fleet Activities Yokosuka for a 16-day port call. In December she was back at the Olympic Pier after that second 4-month deployment.
Until January 18, 2025 she had five-day underway routine operation and also until Jan. 21, with personal transfer at Dungeness Spit. By February 16, she stopped underway at Pearl Harbor for personnel transfer and again on the 18th., then unloaded weapons at the Ammunition Pier on Naval Magazine Indian Island on Feb. 24- March 1 and back at Olympic Pier on March 1. By September she departed Kitsap for sea trials after her six-month Selected Restricted Availability (SRA). She had a shakedown via Pearl Harbor on October and by December she is back like each year, but moored that year at Berth 13S on Fleet Activities Yokosuka, with the cres on Xmas and New Year’s leave.

USS Connecticut was laid down at General Dynamics Electric Boat, Groton on 14 September 1992, launched on 1 September 1997 and commissioned on 11 December 1998. She is the 5th active United States Ship to be named for the U.S. state of Connecticut all the way back to 1776. She is the only one in class to be named after a state in class, making naming these boats an odd job: One was named after the second US SSN, a goundbreaking step back in the 1950s, and another named after a president, something usually reserved to aircraft carriers. The naming convention would have normally be of cities though. States are usually reserved to SSBNs.

Anyway, the contract to build her was awarded to the Electric Boat Division, General Dynamics Corp. in Groton in her namesake state of Connecticut like her sister. The cold war on 3 May 1991 was not yet over (historians still debates this). Her keel however was laid down on 14 September 1992, almost a year after the collapse of USSR. She was launched and sponsored by Patricia L. Rowland, wife of the Governor of Connecticut. After her commission in December 1998 the crew had some rest at the New year’s eve before undergoing a gruelling six months shakedown operations and a cycle of evaluations of her weapons systems, sensors, and engineering departments. She broke this routine to Joint Task Force Exercise 2-99 in, the “red team”, the opposing force, while completing acoustic trials and a shallow water exercise as well as an ASW (anti-submarine warfare) exercise, probably not found by her designated adversaries as designed.

In September the same year, she started her Post-Shakedown Availability (PSA) at Electric Boat, ironing out all her defects. The amount of PSA work grew quite a lot, and this submarine broke records as the entire submarine force’s most demanding PSA, albeit this was all completed ahead of schedule and claimed as the safest in the century long history of Electric Boat.

2000, 2001 and 2002 saw her in classified missions. In April 2003 for the first time she surfaced through the Arctic ice close to the site of the University of Washington’s Applied Physics Laboratory Ice Station (APLIS). Her IR camera found a polar bear intrigued by her rudder, and gnawing on it for a while before parting away. On 31 March 2004 she was officially taedk to participate on the war on terror, joining USS Wasp Expeditionary Strike Group (ESG). Whzen done, after patrols and strikes, she proceeded home and arroved on the east coast sub base of New London on 2 September. Here, she was greeted by a pierside band blasting Thin Lizzy’s “The Boys Are Back in Town”. From 2005 to 2007 she mostly remained in port for a prolonged maintenance cycle (and probably some cost saving measures along the way).

In early 2007, it was announced she would be transferred to Naval Base Kitsap-Bremerton, Washington’s Puget Sound on the west coast after a last six-month deployment from 25 July 2007 onwards. This was the last of her sisters all transferred from New London to Kitsap. This major realignment saw 60% of the US submarine fleet to the Pacific given the intense buildup of the Chinese PLAN and radical diminution of the threat posed by Russia. She entered Kitsap on 30 January 2008 and joined her sisters at Submarine Development Squadron 5. Classified missions in 2009 and 2010.
By early 2011, she took part in her first in ICEX 2011, a whole realistic warfare scenario in an Arctic environment, honing navigation and protocols of submarine warfare under ice.

USS Connecticut then had a whole serie of extensive overhauls from 2012 to 2017. Back in action by early 2018 she took part in the next Arctic ICEX 2018 as a major arctic readiness exercise. Later that same year she made her third WestPac (western Pacific depoloyment) before sailing back on 30 January 2019. From 26 March to 19 August 2019 she was again in maintenance and modernization, in Puget Sound Naval Shipyard’s drydock for a budget of US$17 million committing 30,000 worker days. For the first time she used hull-climbing robot inspecting her hull, searching for cracks and defects in her acoustic tiles layer. IO,ce out of the drydock she sailed to Bangor and remained moored at the pier alongside USS Seawolf and USS Jimmy Carter at this new Naval Submarine Base.

On 14 April 2021 as she proceeded to her pre-deployment training, she hit a pier in Point Loma (California), which prompted a separate command investigation and navigation safety stand down for inspection. On 2 October the same year she was again damaged after a collision underway underwater with a seamount while in the South China Sea. Eleven sailors were injuried but there were no fatality. USS Connecticut’s propulsion, helped by the extyensive rafting presumably preserved it from the schock and it continued operating normally. The investigation found the commanding officer, his executive officer, and boat’s chief guilty of negligence and relieved of duty. Repair work started in drydock at Puget Sound in 2023 with a scheduled time frame of 43 months. For the moment she is planned to return to the South China Sea by September 2026. More to come in the future.

USS Jimmy Carter is the third and last boat in class, also the only one named after a president, something generally unheard of for a submarine. A special status on par with aicraft carrier, a choice that underlined hger very special status as a submarine. This was the reflection of how much she was modified to her new role. In any case, USS Jimmy Carter, president between 1971 and 1975 in a post-Vietnam context of defense cuts (also under CNO Zumwalt) received the identifier SSN-23. Carter was also a former submariner and nuclear specialist. Only submarine to have been ever named for a living president, she is the third of the US Navy, to have been named for a living person.

Technical Details

Former President and Navy submariner Jimmy Carter (left) hoists a replica of the USS Jimmy Carter (SSN 23) given to him by Secretary of the Navy John H. Dalton (right) at a naming ceremony in the Pentagon on April 28, 1998. The USS Jimmy Carter is the last of the Seawolf class submarines to be built for the U.S. Navy.

She was to be initially awarded to General Dynamics Electric Boat, Groton, in 1991, like her sister Connecticut as planned by the Congress back in the 1980s. However the construction was suspended for reassessment in the new post-cold war/peace dividends context, until she was formally awarded on 29 June 1996 when the design was approved, and laid down two years later on 5 December 1998. She was launched on 13 May 2004 and commissioned on 19 February 2005 as the largerst SSN ever built in US History and certainly the longest nuclear attack submarine (no SSGN), longer and heavier that the famous “40 for freedom”, SSBN in cold war service.

However her construction was truly special and took delays: Original schedules were a commissioned in late 2001 or early 2002. However Electric Boat was awarded an $887 million extension of contract on 10 December 1999. The object was to modify the newly built hull for testing new submarine systems for classified missions and replaced the old USS Parche, a 1970s Sturgeon class in these missions. During these extensive modifications, her hull was extended 100 feet (30 m), helped by the modular approach of submarine construction adopted at the time. This supplementary 2,500-ton amidship section hosted the entirety of the Multi-Mission Platform (MMP). This addition comprised the follwojg assets (for those known publicly):
-An ocean interface for divers
-A Reconfigurable Cargo Area
-Modular stowage of SOF supplies
-Remotely operated vehicles (ROVs)
-Command Center Suite for mission planning
-Pressure-resistant passage for the crew
-Accommodation the module’s crew, berth up to 50 SOF personnel.
-Special operation equipment:

• ROV heavy duty handling system (several ROVs, margin for up-scale)
• Dry Deck Shelter
• Advanced SEAL Delivery System for Special Operations Forces (SOF)
• Storage paces and all the gizmos to lift and carry these to their exit bays
• Dedicated deployment space for mission systems
• Gear to retrieve and deploy weapons, countermeasures and sensors

This of course, changed many metrics like a length now of 128.5 m (421.6 ft) at the waterline and displacement of 12,139 tons fully submerged, albeit core features remained the same. Armaments wise, she kept her eight 26.5 inch torpedo tubes sleeved for 21 inch weapons with up to 50 Tomahawk land attack missile or Harpoon anti-ship missile as well as the standard Mk 48 guided torpedo. Another difference was her maneuvering devices (shrouded props) fore and aft to keep station over selected targets in shallow waters an strong currents for sea bottom operations. Intel analysts speculate it’s for having an underwater splicing chamber for optical fiber cables and just tap on underwater communication cables. Most of the details about the whole new structure is of course classified, specs ops obliges.

As Seawolf

⚙ J.Carter specifications
Displacement	7,568 tons light, 12,139 tons full, 1,569 tons dead
Dimensions	138 x 12.1 x 10.9m (452.8 oa x 39.7 x 35.8 ft)
Propulsion
Speed	As Seawolf
Armament	As Seawolf
Sensors	As Seawolf
Crew	15 officers, 126 enlisted

Career

With all this, Jimmy Carter was christened on 5 June 2004, sponsored by former First Lady Rosalynn Carter (The president passed out however in December 2024, just a year ago). She was indeed commissioned more than six years after USS Connecticut, four months after USS Virginia, first of the next-gen Virginia-class SSNs.

On January 24, 2004 Cmdr. David Bartholomew, Jr., first CO for the Pre-Commissioning Unit (PCU) was relieved of command due to a “loss of confidence” by Capt. Robert D. Kelso, deputy chief of staff of Submarine Development Squadron 12 in New London, as a temporary command and by June 5, she was christened in a new ceremony at GD’s floating dry-dock as said above. By November 19, she returned at EB shipyard after a very first three-day underway test, the Builder’s (Alpha “A”) trials.

On February 19, 2005 she was officially commissioned at a ceremony at Pier 17S, New London base in Groton. On August 12, she was sent to Naval Submarine Base Kings Bay after a brief VIP cruise from Port Canaveral, with Jimmy Carter and his wife on board. On November 9, she arrived after a Panama transit at her homeport of Naval Base Kitsap at Bangor, Washington, West Coast. There, she replaced the USS Parche (SSN 683), decommissioned in October 2004. On August 16, 2006 her new CO was Cmdr. David A. Honabach, after she had a “deperm” at the Magnetic Silencing Facility at Naval Base Kitsap-Bangor. On November 11, she was back to Bangor after a 4-month deployment. She then entered the Puget Sound Naval Shipyard for an routine overhaul.

On March 2, 2012 Cmdr. Brian P. Elkowitz relieved CO Brian L. Davies with a ceremony held at the Naval Undersea Museum in Keyport. So far she had completed two deployments, of course highly classified. By January 20, 2013 she departed Kitsap for a new western Pacific deployment and by March 5, she transited by Pearl Harbor-Hickam (six-day port call) for emergent repairs and personnel transfer on April 27. Two days later she made a liberty port visit and was back home on May 9. On June 3, she was at Puget Sound for a Drydocking Phased Maintenance Availability (DPMA) from June 6 to August 2014 and post-refit trials in September.

On October 30, USS Jimmy Carter stopped at Naval Base Point Loma (San Diego) for personnel transfer and also on Nov. 6. On January 23, 2015 she departed Kitsap for routine training via Point Loma and back in March. On May 29, CO Melvin R. Smith, Jr., relieved Elkowitz at Kitsap. On September 19, she stopped at Kilo Pier Naval Air Station North Island, San Diego for a 12-day port call and back home on October 13. By December 13, she was moored at Kilo Pier, NAS North Island. On February 11, 2016 she stopped at Point Loma (again for personnel transfer), March 9 and March 14. On October 8 she left Kitsap, stopped at Point Loma and joined USS Carl Vinson (CVN 70) CSG’s Composite Training Unit Exercise (COMPTUEX) as part of the “red forces”. She was Moored at Sierra Pier in NB Point Loma between October 31- Nov. 3 and on November 22, then back to Bangor on Nov. 26.

On April 14, 2017 she returned at Kitsap after a deployment but back again in June, via Point Loma in June-July. She then proceeded to a three-month patrol. On October 6, Cmdr. Edward K. Floyd relieved Smith Jr. as CO at the Naval Undersea Museum in Keyport. On January 13, 2018 she stopped at Point Loma and by December was at Puget Sound for an Extended Drydocking Selected Restricted Availability (E-DSRA). On July 10, 2019 she returned to Delta Pier, Naval Base Kitsap-Bremerton after her post-refit sea trials. She made more in August. On September 9 she stopped underway in deployment for personal transfer at Pearl Harbor and again on the 13th. Likely in december she was in Dry Dock #5 on Puget Sound Naval Shipyard. By June 2, 2020 she undocked just after midnight at the Service Pier at Kitsap-Bangor while departing for post-refit sea trials in October and November. On November 29, she was transferred to the and stopped at Dungeness Spit, Juan de Fuca for personnel transfer and probably back home in December, when Cmdr. Benjamin P. Grant relieved Cmdr. Edward K. Floyd as CO on the 18th.

By January 28, 2021 USS Jimmy Carter left Kitsap for routine operations via Dungeness Spit, Port Ludlow, Dungeness Spit again in March and back home on March 17, then at sea on May 24, stopping in June at Point Loma, Sierra Pier several times, and back to Kitsap on July 10, then at sea on August 31. On September 6, she stopped at Point Loma, also on the 9th and 16th and back to Kitsap, then at sea on September 25, and back on October 13-17. On January 2022 she stopped at Dungeness Spit for personnel transfer, Jan. 8 and 14th and back home in April 10 after a three-month deployment for the 3rd Fleet AoR and in May. She was back home on June 14, then underway on August and September, stopping off Dungeness Spit in October for another WestPac. On January-February 2023 and May she made another short deployment. In June she was back at Kitsap, but departed on June 15-19, June 26 to July 2, July 6-8 and July 15, with a stop at Dungeness Spit and back home on July 26, thena way on August 4 and back in November after a new three-month deployment.

On January 11 2024 she was back at sea, on the 16th, she stopped off Naval Base Point Loma (also April 23, 25, May 1, 3rd) and back home on May 7, after an unconfirmed 4-month deployment. In July she was back at Kitsap after routine operations and Dry Docked at the #6, Puget Sound Naval Shipyard for her DCMAV from Aug. 21. After completion by February 4, 2025 she had sea trials from March 11-15, March 26 to April 3 and April 8-17, then April 25. On the 29th she stopped at Dungeness Spit, also on May 7 and 12th, back home on May 19 and at sea on July 3. On the 8th she stopped at Point Loma as on July 15, 21, 25, August 1 and the 6th, back home 4 dats later at Kistap, underway on the 24th, and by December 11, moored at Kitsap-Bangor after her three-and-a-half month classified deployment. More to come in future updates.

Read More/Src

Links

On man.fas.org
secretprojects.co.uk
nationalinterest.org
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Validation of the Use of Low Enriched Uranium as a replacement for Highly Enriched Uranium in US Submarine Reactors, MIT
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