U.S. SUBMARINE DESIGN IN THE 20th CENTURY

Innovation is a warfighting skill. Emergence of American submarines was made possible by the innovative genius of John P. Holland. During the 20th century. the U.S. Navy commissioned 454 conventional submersibles in 58 classes and 192 nuclear submarines in 19 classes.

In this brief review. noteworthy designs. ranging from revolutionary to failures. will be presented in order of hull number. Surface displacement (NSC) and submerged displacement (SUBD) are in long tons. Commentary will be offered. if salient. on selected characteristics. We shall concentrate on hull design and propulsion machinery. Limited space precludes coverage of sensors and most weapons. A short bibliography is appended. Design eras noted in Jackson et al (1986) provide a framework for design motivation.

Genesis: Coastal Defense Submersibles

Boats in this era all bad 17. 7 inch torpedo tubes. gasoline engines and single hulls. HOLLAND was a body of revolution (BOR) hull with a single screw designed for operation submerged. C-1 OCTOPUS had twin screws and two engines, which became the norm.

John Holland (1841-1914) was truly the Father of the Modem Submarine. His genius was underscored by the appreciation of simplicity and common sense. Two of his diving principles were:

• A submarine should dive like a porpoise and rise like one.
• A submarine should have a fixed center of gravity submerged, and its water ballast tanks should completely fill.

All modem submarines still work the same way.

Early submarine design was dominated by Electric Boat Company (EB) (John Holland resigned from EB in 1904) and, to a lesser extent, Lake Torpedo Boat Company (Lake).

Simon Lake (1866-1945) has been characterized as one of the finest examples of the Yankee inventor. Early on, he espoused trainable torpedo tube nests in the superstructure.

The Diesel Revolution

E-1 had two Vickers 275 bhp four cycle diesels built by New London Ship & Engine Company (Nelseco). With air blast injection. EB boats would have Nelseco engines until 1925. This class had the first bow planes.

G-3 was lake’s first diesel boat. It was fined with two Busch Sulzer 600 bhp two cycle engines. All subsequent Lake boats would have Busch Sulzer diesels.

K-1 and L-1 {both EB built) were provided with Nelseco-Machinenfabrik-Augsburg-Nilmberg (Nelseco-MAN) two cycle diesels which were very unreliable. During the Great War, we deployed four K-Boats and E-1 to the Azores and seven L-Boats to Bantry Bay, Ireland. Despite highly motivated crews, coastal boats with cranky engines simply were not up to the task at hand.

SCHLEY was fitted with two 17. 7 inch twin trainable external tube nests, but this was not a success and they were removed. Four Nelseco 1000 bhp diesels as built; direct drive with two in tandem on each shaft. Serious vibration problems. First double bull and endurance improved to 3000 nm @ 14 knots. Achieved 20 knots during surface trials, a fleet submarine goal. Sea-keeping difficulties. All three in class laid up by 1927.

R-1 was our first class with 21 inch torpedo tubes. All subsequent front line U.S. designs would be fitted with 21 inch tubes, until current SEA WOLF.

In 1915, Constructor Emery S. Land was assigned to the Bureau of Construction and Repair (BuC&R) preliminary design office. He favored an open ocean submarine of about 800 tons NSC, not quite a fleet submarine. A partial double hull was considered preferable to a single hull for boats larger than 800 tons NSC.

In order to challenge EB and Lake design dominance, three prototypes were ordered to general specifications. EB (S-1), Lake (S-2), and Portsmouth Naval Shipyard (PNSY) (S-3) were allowed to develop their own detailed plans. S-1 was single hull; the other two were double hull. Despite having had six superior German war prize U-Boats in our hands since 1919, their characteristics were not factored into S-Boat designs. Fifty-one were delivered between 1919 and 1925 (EB 31, PNSY 11, Lake 9).

S-10 through S-13 (PNSY) had one stem tube and a total of nine reloads. S-48 through S-51 (Lake) had the same additional tube but 11 reloads.

Lake’s Busch Sulzer engines worked well. Seven PNSY boats had Nelseco engines and four were built with U.S. licensed versions of MAN engines built at New York Navy Yard (BuMAN).

All other deficiencies were overshadowed by Nelseco problems. Vibrations at critical engine speeds caused crank shaft failures and damage to pistons, cylinders, and cylinder heads.

The Bureau of Engineering (BuENG) held EB/Nelseco responsible for a poor design. EB disagreed and stopped work on their boats in 1921. Production resumed in early 1922.

Simon Lake went out of business in 1924. EB received no U.S. construction contracts between 1925 and 1932.

Three U-Cruiser monsters were placed in service between 1928 and 1930, two at PNSY and one at Mare Island Naval Shipyard (MINSY). ARGONAUT (PNSY) was our only minelayer, carrying 60 Mk XI mines launched through two 40 inch diameter stem tubes. All three had two 6 inch deck guns. NARWHAL and NAUTILUS carried hefty torpedo loads.

Diesel Direct Drive (DDD) and Diesel Electric Drive (DED). DOD: two BuMAN 1400 bhp diesels. OED: one BuMAN aux engine driving a 300 kw generator. Two 1100 hp main motors. She was underpowered and ungainly submerged. Never used as a minelayer.

Enhancement of Surfaced Performance: The Fleet Submarine

In 1926 the Submarine Officers Conference (SOC) was established to advise on operational characteristics of submarine designs. Andrew McKee, a brilliant designer, came to BuC&R at about the same time. This combination of operator inputs and design perspicacity gave BuC&R and BuENG a refreshing outlook. It was decided to adapt selective characteristics of U-135 (a successful WWI Gennan U-Boat) to U.S. designs. Under the guidance of McKee, DOLPHIN (NSC 1718 tons) emerged.

DOLPHIN was a precursor to the fleet type submarine. Partial double hull. Max surface speed 17 knots. Surface range: 600 nm @ 10 knots. DOD and OED. ODD: two 1750 bhp BuMAN diesels. DED: two 450 bhp BuMAN diesels driving two 300 kw generators. Two 875 hp main motors and two 25 hp creep motors.

In 1932, a diesel engine competition was launched by BuENG. Three designs were accepted:

• General Motors (GM) 201A, a 12 cylinder two cycle V-type railroad engine
• Fairbanks Morse (FM) 38A 8, an eight cylinder two cycle opposed piston type
• Hooven-Owens-Rentschler-MAN (HOR), an eight cylinder two cycle double acting. (Double action means ignition both above and below the piston.)

All of the early versions of these engines had problems, but the HOR failures were devastating. Work horse replacements were GM 278A and FM 380 8 1/8. The last of the 21 HOR boats was not re-engined until mid 1944.

In the late 1930s the SOC established characteristics of an ideal all purpose fleet boat. TAMBOR keel was laid on 16 January 39. Partial double hull, welded. Max surface speed 20 knots. Range on surface 11,000 nm @ 10 knots. OED with motor to shaft reduction gears. Four GM 16-248 1535 bhp diesels driving four 1100 kw main generators. Two aux generators. Four 1375 hp main motors.

The ultimate work horse submarine of WWII was the Gato class, and its design was frozen for mass production in 1940. That same year. BuC&R and BuENG were merged to form the Bureau of Ships (BuShips). Gato characteristics were about the same as TAMBOR, except that test depth was increased to 300 feet.

The Balao class had the same general characteristics as Gato, except test depth was 400 feet. Also, in 1944, new boats of the class were provided with slow speed main motors, eliminating noisy reduction gears.

Toward the end of the war, Armand Morgan, who had been responsible for submarine design at BuC&R/BuShips since the late 1930s, observed: “[T]he leadership, direction, interest, and demands of the operating personnel were a major, if not the major, force leading to the success of our designs.”

Emphasis on Submerged Performance

DOLPHIN, our only diesel battery boat still in service, is a valuable deep-diving asset for ASW and oceanographic research.

Submerged performance of the revolutionary German Type XXI boat was impressive. She could make 17 .2 knots submerged and go 285 nm@ 6 knots on the battery. Evaluation of U-2513 and U3008 began in September 1945. Performance reports provided some guidelines for our first post-war attack boat, TANG.

The two stern tubes were for swim-out torpedoes only.

TANG and three others were equipped with four GM 16-338 high speed pancake diesels rated at 1000 bhp each at 1600 rpm. Two boats were fitted with three FM 8-38A 6 3/4 high speed opposed piston engines with revised ratings of 1335 bhp at 1335 rpm. Neither engine design had been properly proof tested before installation. The pancake engines had the most serious problems, and all six boats were eventually re-engined with three FM 8-38ND 8 1/8 engines rated at 1500 bhp at 850 rpm.

Postwar planners envisioned lots of small killer submarines in barriers across the Greenland-Iceland-United Kingdom (GIUK) gap on guard against surging Soviet submarines. K-1 grew in size and sophistication as she emerged and lacked habitability for such a role, particularly in the unforgiving North Atlantic.

ALBACORE represented a giant leap forward in submarine design and return to a BOR hull form and single screw 50 years after HOLLAND. As a research submarine. she took on many configurations for evaluation. and BuShips was given a free hand.

Highlights included:

• Phase I: Cruciform stem with control surfaces aft of the propeller. Retractable bow planes.
• Phase II: Cruciform stem with control surfaces forward of the propeller. Bow planes removed.
• Phase III: X-stem with control surfaces forward of the propeller. Superb control and maneuverability.
• Phase IV: X-stem with control surfaces forward of two contra-rotating propellers. Two lengths of shaft were installed to study effects of separation of the propellers. Closer was the best.

The influence of ALBACORE on future designs reverberated throughout the major navies of the world.

Dr. Ross Gunn of the Naval Research Laboratory (NRL) pondered the prospects of using nuclear fission as a source of energy for submarine propulsion in early 1939. He and Dr. Philip Abelson contributed to an NRL report (April 1946) on “The Atomic Energy Submarine”. In June of that year. Captain Hyman G. Rickover was assigned by BuShips to lead a small group of colleagues to study power piles at Oak Ridge. Tennessee. On 9 June 1947, Admiral Chester Nimitz, Chief of Naval Operations (CNO). approved development of nuclear propulsion for submarines.

Design and construction of NAUTILUS was an enormous task. and it is truly amazing that she made it to sea just seven and a half years after Rickover first arrived at Oak Ridge to start the process.

All U.S. nuclear pressurized water reactor (PWR) systems work basically the same way, with some differences in natural circulation plants. A submarine thermal reactor (STR) uses water as a coolant and moderator to produce slow (thermal) neutrons in the core and sustain criticality. Reactor manufacturers are identified by the last letter in a reactor designator, e.g., W (Westinghouse), G (General Electric). and C (Combustion Engineering). Most engine rooms contain geared turbines driven by saturated steam delivered from steam generators in the reactor compartment.

NAUTILUS was fitted with an S2W power plant.

X-l, our only midget so far, was an important failure. Con· ceived at PNSY as a diesel battery craft, her design was turned over to Fairchild Engine Division of Fairchild Engine and Airplane Corp., and a peroxide diesel boat emerged. Highly concentrated unstabilized hydrogen peroxide was used to produce oxygen for running a diesel engine submerged. On 20 May 1957, an explosion in the peroxide storage bag in the bow section taught us that high concentration hydrogen peroxide has no place on a fighting ship.

SEA WOLF’s reactor used sodium/potassium as coolant. Intermediate speed neutrons (SIR) were used to sustain fission. Arrangements to deliver super heated steam to the engine room failed because of metallurgy problems in the super heater. With only saturated steam available, SEA WOLF could not achieve design speed, and her S2G reactor was replaced with a PWR plant.

SKA TE, a scaled down version of NAUTILUS, was fitted with an S3W plant, the first with vertical steam generators, which became the norm. Stem tubes swim.out only. On 17 March 1959 she became the first ship in history to occupy the surf ace at the geographic North Pole.

BARBEL, a militarized version of ALBACORE, became an essential precursor to SKIPJACK.

Final Transition to Nuclear Powered BOR True Submarine

Marriage of nuclear power to the ALBACORE hull made SKIPJACK the ultimate leap forward. Powered by an SSW reactor, she was fast and highly maneuverable, but noisy.

TRITON was our only twin reactor (S4G) submarine. She was designed for radar picket duty, with emphasis on surface performance (27 knots). By the time TRITON entered service, the mission had been taken over by carrier-based aircraft. In 1960 she circumnavigated the globe submerged.

Noise reduction efforts resulted in two designs-THRESHER and TULLIBEE. Emphasis was on silence and ASW prowess.

THRESHER’s engineering spaces were carefully designed for quiet operation. Her sail was much lower and smaller than SKIPJACK’s. She was fitted with an SSW reactor, which became the norm until LOS ANGELES.

TULLIBEE, one of a kind, was equipped with an S2C reactor. She had a turbo-electric plant, which was very quiet. Her torpedo tubes were angled off the center line to accommodate a large spherical sonar array forward, an arrangement which became the norm.

GEORGE WASHINGTON was another magnificent marriage-that of a BOR nuclear powered hull with a weapons compartment of 16 vertical solid fuel ballistic missiles. A Skipjack class hull on the ways was cut in two and a missile section was inserted under the leadership of Commander Harry A. Jackson.

Conceived in 1955, fortuitous advances in technology and application of the highest possible priority under the leadership of Rear Admiral William F. Rayborn, resulted in a successful launch at sea by GEORGE WASHINGTON of two A-1 (1200 nm) missiles on 20 July 1960. This was an historic accomplishment that overshadowed introduction of any previous weapon system.

In a little over seven years and three months, 41 SSBNs had been commissioned.

JACK, a member of the Thresher class, had an innovative power train. She had contrarotating screws driven by a single turbine with contrarotating blade assemblies in the same housing. No reduction gears. Some observers have wrongly maligned the concept of contrarotating propellers. ALBACORE operated successfully with hers for eight years, and JACK’s worked well. Speed can be significantly increased with them.

LAFAYETTE was an advanced SSBN which embodied improvements over earlier designs. Machinery quieting and better interior arrangements emerged. She was built to carry A-2 (1500 run) and A-3 (2500 run) missiles. Later launching equipment conversions were to C-3 (2500 nm) and C4 (4000 run) missiles.

STURGEON was an extension and improvement of the THRESHER design. A higher and longer sail provided space for more masts and antennae, and better seakeeping at periscope depth. She was very quiet. This class became a workhorse in the Arctic.

NARWHAL, a lengthened STURGEON, was fitted with an S5G natural circulation reactor and a direct drive slow speed turbine. No reduction gears. Very quiet at speed. No main coolant pumps running, and with scoop feed of cooling water to the main condensers, no circ pumps on. Very innovative and reliable power plant throughout a long life (29 years) .

NR-1, the smallest nuclear submarine in the world, is a deepdiving highly maneuverable research and salvage craft.

GLEN ARD P. LIPSCOMB represented another effort to improve silent running with turbo-electric drive.

The Los Angeles class (62 units) is the longest peacetime submarine production run in our history. Beyond hull number SSN 719, 12 vertical launch tubes for Tomahawk missiles were installed between the sonar dome and the forward cap of the pressure hull. After SSN 751, retractable hull bow planes were provided instead of sail planes for Arctic capability. SSN 768 and later have better quieting and a few of the last units, including SSN 773, have pumpjet propulsors.

The mammoth Ohios have 24 launch tubes each. Four of the earliest units were built to handle C-4 (4000 nm) missiles and were not upgraded. SSBN 734 and beyond were built with D-5 ( > 4000 run) capability, and SSBN 730 through 733 were backfitted for D-5. SSG natural circulation reactor.

The newest SEA WOLF (SSN 21) is an expensive and powerful submarine that was designed to fight the Cold War. She is powered with a pump-jet arrangement, and her reactor core will last the life of the ship. S6W reactor. Torpedo tube diameter is 26.5 inches. The 21st century is here. There is still time to assign traditional hull numbers to this class of three.

Overview

The first 100 years of submarining has been an exciting ride. Sadly, however, we have suffered two tragic nuclear losses: THRESHER on 10 April 1963 and SCORPION on 21May1968.

Hammering away at diesel problems in the 1920s, ’30s, and ’50s was not a pleasant task.

In general, the reliability of reactor plants has been magnificent. Burnable poisons and other sophisticated design techniques have also extended core life from 26 months (NAUTILUS) to the life of the ship (SEA WOLF).

The post Cold War drawdown has forced retirement of perfectly good Los Angeles class boats with 15 years of life remaining. This seems irrational, particularly when the present number (about 56) of attack boats is not enough to meet current operational commitments. An encouraging effort is in progress (July 2000) to refuel several 688s and thereby help maintain our inventory.

Electric drive, described as significant as the change from sail to steam, is the wave of the future. In June 2000, plans to introduce it were revealed. The first unit, a modified Virginia class, to be authorized in 2010, will be delivered in 2016.

Submarines have advanced in the past century from coastal craft to indispensable, stealthy and versatile capital ships. Hopefully, future innovation will recognize the value of maneuverability and produce a smaller, simpler and less expensive class to complement the heavy payload early Virginias.