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Tennessee Class, U.S. Battleships


Photograph of Tennessee-class battleship

National Archives #19-N-45071

Schematic diagram of Tennessee class battleship

ONI 222

Specifications:

Tonnage 32,600 tons standard displacement
Dimensions 624' by 97'6" by 30'2"
190.20m by 29.72m by 9.2m
Maximum speed       21.5 knots
Complement 1401
Aircraft 2 catapults
3 seaplanes
Armament 4x3 14"/50 guns
12x1 5"/51 guns
8x1 5"/25 AA guns
Protection About 9660 tons or 30% of displacement:

13.5" (343mm) belt tapering to 8" (203mm) below the waterline

2" STS + 1.75" STS + 1.75" NS = 4.2" (51mm STS + 44mm STS + 44mm NS = 107mm) armor deck

3" STS + 1.75" STS + 1.75" NS = 5.3" (76mm STS + 44mm STS + 44mm NS = 134mm) armor deck over magazines

4.5" STS + 1.75" MS = 5.5" (114mm STS + 44mm MS = 158mm) over steering spaces

1" STS + 0.5" MS =1.3" (25mm STS + 13mm MS = 33mm) splinter deck

13" (330mm) bulkheads tapering to 8" (203mm) below waterline

18"/7"STS/10"/9" (457mm/178mm STS/254mm/229mm) turret

13" (330mm) barbettes

Splinter protection for 5"/25 guns

16"/6" (406mm/152mm) conning tower

9" (229mm) uptakes

17'3" (5.3m) underwater protection consisting an outer void compartment, two liquid compartments, and an inner void compartment with a holding bulkhead.  This was designed to withstand a 400 lb (181 kg) explosive charge.
Machinery
4-shaft turbo-electric (26,800 shp)
8 Babcock & Wilcox boilers
Bunkerage 1903 tons fuel oil
Range 5240 nautical miles (9700 km) at 12 knots
8000 nautical miles (14,800 km) at 10 knots
Sensors
CXAM1 air search radar
Modifications

Tennessee:

Early 1942: Added 4x4 1.1" antiaircraft guns and 16x1 20mm Oerlikon antiaircraft guns. Two 5"/51 guns removed and FC and SC radar added.

1942-6: 2x4 1.1" guns added.

1942-9: Began major modernization. Beam increased to 114' (34.7m) with torpedo blisters. All 5"/51 guns removed. 4x2 5"/38 dual-purpose guns added.  Light antiaircraft consisted of 10x4 40mm guns and 43x1 20mm guns. Conning tower replaced with 5" (127mm) tower. Internal subdivision improved. Splinter deck and turret roof armor increased to 7" (178mm). Final displacement 39,500 tons and speed reduced to 20.6 knots.

California:

Resembled the modernized Tennessee following repairs from 1942-6 to 1944-1. However, light antiaircraft was 14x4 40mm guns, 40x2 20mm guns.


The Tennessees were completed in 1920-1921. The Navy initially considered a radical design with armor sloped by as much as 45 degrees ("Ironsides"), but abandoned this due to stability concerns and chose a conventional design based closely on the New Mexicos. They were good ships, with turboelectric drive that improved subdivision. They were surprisingly maneuverable, being able to reach full speed in just three minutes and with a tactical diameter of 700 yards.

The most significant new feature of the ships was a novel underwater protection system, based on extensive caisson experiments. The system consisted of four compartments separated by thin bulkheads. The outermost and innermost compartments were void while the middle compartments were liquid-filled, and the bulkheads were designed to resist deformation as much as possible and then tear with as little fragmentation as possible. The effect was that most of the force of a torpedo explosion would be expended in the void spaces while the liquid layers absorbed fragments, leaving the inntermost holding bulkhead intact to prevent flooding of the spaces beyond. The system was judged capable of resisting a 400 lb (181kg) explosive charge. It was the best engineered system in the world at the time, and its principles were duplicated on all subsequent U.S. battleships as well as many foreign battleships.

Another improvement was the use of turrets that could elevate their guns to 30 degrees, which increased their range by about 40% over earlier ship classes (which could only elevate their guns to 15 degrees). This was judged valuable enough that the older ships were eventually modified to elevate their guns to 30 degrees as well.

Tennessee was lightly damaged in the Pearl Harbor attack, taking just two bomb hits, though her aft section was badly damaged by flaming oil from the Arizona. While under repair, Tennessee added considerable antiaircraft armament and radar. Once new battleships began arriving in the Pacific, she was taken in hand for a major modernization that left her with a superstructure resembling South Dakota

The two torpedoes that hit California at Pearl Harbor failed to penetrate her torpedo defense system. However, she had ten or twelve access hatches to her torpedo defense voids opened for inspection, which allowed water to flood freely into the ship. She was later raised and repaired, undergoing her own extensive modernization, and participated in the final offensives of the war.

Photo Gallery

Tennessee class in profile as constructed

NARA

Tennessee class in profile after modernization

NARA

Tennessee after Pearl Harbor attack.

U.S. Navy

Forward turrets and superstructure of
                Tennessee-class battleship

U.S. Navy

References

DANFS

Friedman (1985)

Whitley (1988)

Worth (2001)

Zimm (2011)


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