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South Dakota Class, U.S. Battleships


Photograph of South Dakota-class battleship

Naval Historical Center #97263

Schematic diagram of South Dakota class battleship

ONI 222


Specifications:

Tonnage 37,970 tons standard displacement
Dimensions 680' by 108'2" by 36'2"
207.26m by 32.97m by 11.02m
Maximum speed       27 knots
Complement 2257
Aircraft 2 catapults
3 seaplanes
Armament 3x3 16"/45 guns (130 rounds per gun)
8x2 5"/38 dual-purpose guns (300 rounds per gun plus 50 illuminating rounds per gun)
5x4 1.1" AA guns
34 20mm Oerlikon AA guns
8 0.50 machine guns
Protection11,400 tons or 30% of displacement:

12.2" (310mm) main belt of Class A armor sloped 19 degrees and backed by 0.75" (19mm) STS

12.2" (310mm) lower belt of Class B armor tapering to 1.75" (44mm) below the waterline, sloped 19 degrees and backed by 0.75" (19mm) STS

1.25" (32mm) outer STS decapping shell

1" (25mm) STS splinter bulkhead behind main belt

5.3" to 5" + 0.75" (135mm to 127mm + 19mm) STS armor deck

0.625" STS upper hull sides

1.5" (38mm) STS weather deck

0.625" (16mm) STS splinter deck over machinery spaces

1" (25mm) STS magazine crown

1.5" STS magazine sides and machinery bulkheads

13.4" (340mm) bulkheads tapering to 1.75" (44mm)

13.5"/11.3"/4.75" (343mm/287mm/121mm) steering side/rear/crown

18"/7.2"/9.5"/12" (457mm/184mm/241mm/305mm) turret front/roof/side/rear

17.3"/14.8"/11.5" (439mm/376mm/292mm) barbette beam/front/rear

2" (51mm) STS secondary battery

15"/7.25" (381mm/184mm) conning tower sides/roof

17'11" (5.5m) 4-bulkhead void-liquid-liquid-liquid torpedo protection (0.625", lower side armor belt, 0.625", 0.875" or 16mm, lower armor belt, 16mm, 22mm bulkheads from inboard to outboard) designed to withstand a 700 lb (318 kg) explosive charge and resist underwater shell hits.

Machinery
4-shaft General Electric geared turbine (130,000 shp)
8 Babcock & Wilcox three-drum boilers
Bunkerage 5872 tons fuel oil
Range 15,020 nautical miles (27,820 km) at 15 knots
Sensors SC2 search radar
SG surface search radar
FC fire control radar
FD fire control radar (four sets)
FH fire control radar (two sets)
Modifications
All but South Dakota launched with 10x2 5" guns, 6x4 40mm Bofors AA guns in place of 1.1" guns, 35 20mm guns, and no 0.50 machine guns.

1942-11: South Dakota has a total light antiaircraft battery of 16 0.50 machine guns, 17x4 40mm guns, and 57 20mm guns. All other units have 10x4 40mm guns.

1943-2: South Dakota has all her 1.1" guns removed and has a total of 17x4 40mm guns. Other units have 12x4 40mm guns. All units upgrade radar to 2 SG sets, SK, FC, four FD Mark 12 and two FH sets.

1944: Upgrade radars to 2 SG, SK-2, SU, four FD Mark 12 and two FH sets.

1945: All units end the war with a light aircraft battery of 12x4 to 18x4 40mm guns and 52 to 72 20mm guns. Some 20mm guns had to be removed to make room for 40mm guns.

The South Dakota class was designed before North Carolina was even completed.  With war clouds gathering, it was felt that work on the two battleships for fiscal year 1938 should be started at once, even if this meant there would not be time to absorb all the lessons of the FY1937 ships.  Under the Deficiency Authorization of 25 June 1938, Congress approved another pair of 35,000 ton battleships, which resulted in four South Dakotas being built.  By that time, the Iowas were already under design, but Congress specified the actual size of the ships, ruling out another pair of Iowas.

The redesign stemmed from the belief that the North Carolina design made too many compromises.  The new design carried the same main armament, but with increased protection, especially against shells following an underwater trajectory (which had been studied too late to affect the North Carolina design, other than adding simple patches over the magazines). Another issue was that the North Carolinas did not have the space to serve as fleet flagships, so the South Dakota was designed to be a fleet flagship (which is why she had two fewer twin 5"/38 turrets than her sisters).  The other three ships of the class included division flag quarters, like the North Carolinas.

Unlike the North Carolinas, whose main armor belt was the outer surface of the ship, the South Dakotas had their main armor belt included within the hull.  This allowed for a more compact hull design. The initial concept of having a knuckle in the armor, with the top half of the belt angled in toward the ship and the bottom half also angled in toward the ship, was dropped due to weight considerations.  The tapering bottom of the armor belt was included in the torpedo protection scheme, and it was hoped that this would improve the efficiency of the system against both underwater explosions and shells following an underwater trajectory.  Unfortunately, this was not tested on a caisson until after the four ships were well along, and it turned out that this new scheme was less effective than the North Carolina design.  The design of the Iowas was also too far along and the Iowas carried the weaker torpedo protection scheme.  The Montana class would have returned to the better torpedo protection carried by the North Carolina class.

A unique feature of this class was the "tunnel" formed between the two skegs for the outboard propellers.  In order to achieve the desired speed, the cross section of the hull had to decrease, but this could not be accommodated in the beams because of the location of the magazines. Instead, the required decrease in cross section was taken from below the hull, resulting in the tunnel.  This arrangement caused less problems with vibration than in the North Carolinas, but the Navy continued to experiment throughout the war with different propeller configurations to reduce vibration.

A redesigned machinery plant boosted shaft horsepower to 130,000, allowing the South Dakotas to match the speed of the North Carolinas on a shorter hull.  Temperature and pressure were the same as the North Carolinas, 565 psi / 850 degrees F.

The main battery was three triple 16"/45 turrets, the same as on the North Carolina.  While South Dakota had only eight twin 5"/38 guns, the other three ships of the class had ten twin 5"/38.  As designed, the light antiaircraft weapons were three or four quadruple 1.1" guns, but these were quickly replaced with a forest of 20mm Oerlikon and 40mm Bofors guns.

These ships were an interesting contrast with the Yamato class.  With one of the most efficient armor schemes ever applied to a capital ship, and a solid main battery, the four South Dakotas might well have been victorious in a gun duel with the two Yamatos — a roughly equivalent weight match up. 

South Dakota herself was an unlucky ship.  Referred to as "Sodak" or "Battleship X" based on Naval press releases, her crew called her "Big Bastard."  Before seeing action, she grounded on coral at Tongatabu on 21 August 1942.  After being repaired, she provided antiaircraft defense for Enterprise, shooting down 26 attackers and suffering two hits and a near miss.  One bomb hit turret #1, doing little damage to the turret but injuring the captain and 49 other men, one of whom later perished.  The hit also damaged two 16" guns of turret #2 badly enough they were not used in the Naval Battle of Guadalcanal. One of these failed when subsequently tested at the proving grounds.

On the night of 26-27 October 1942, South Dakota collided with destroyer Mahan while trying to avoid a submarine contact.  At the Naval Battle of Guadalcanal, her electrical system shorted out at a crucial moment and the ship blundered into the Japanese line.  Her toughness, and poor Japanese shooting, allowed her to survive, but her unarmored upper works were completely shattered.  The decision to maintain ship control, fire control and flag plot in the heavy conning tower was wise as these suffered little damage.  While she was rendered unable to fight an effective night action, the ship's buoyancy was not affected, and she was able to retire independently.  The Massachusetts experienced a similar occurrence with her electrical system off North Africa, leading to changes in the electrical switchboards aboard all ten new battleships.

South Dakota was hit by a bomb at the Battle of the Philippine Sea that destroyed the captain's and admiral's quarters, and she was saved from destruction in a magazine explosion the next year only by the quick actions of her captain (the legendary "Swede" Momsen, a submarine expert destined for flag rank who was serving his obligatory tour in command of a major surface unit) and her damage control personnel.

Indiana replaced South Dakota on the battle line after South Dakota was damaged in the Naval Battle of Guadalcanal.  Her only serious damage was suffered when she turned out of formation at night and was rammed by Washington.  A torpedo bomber attacked Indiana during the Battle of the Philippine Sea, but gunfire destroyed both the plane and the torpedo moments after it was released.  A kamikaze managed to crash into the side of her hull, but inflicted no damage worse than a dent, though flying debris injured five men.  Indiana was present for the surrender in Tokyo Bay.

Massachusetts first saw action in the Atlantic, where she shelled Casablanca Harbor and the French battleship Jean Bart.  She served in the Pacific for the remainder of the war, providing escort for carrier forces. Massachusetts survived the war, evaded the scrap pile, and is now a museum ship in Massachusetts State.

Alabama first served with the British Home Fleet, then moved to the Pacific.  While screening a carrier task force during the evening of 21-22 February 1944, the aftermost 5" mount, number 59, fired into the rear of the amidships 5" mount, number 55.  One round detonated within the gun mount, killing five and injuring 11.  The Board of Inquiry found that part of the mechanism of the firing cut-out system was exposed and could be inadvertently hit, and a metal cover was installed to prevent a repeat occurrence.  After the war,  Alabama was turned into a war memorial in Mobile, Alabama.

Units in the Pacific:

South Dakota

Arrived 1942-8-21

Indiana

Arrived 1942-11-14

Massachusetts      

Arrived 1942-11-19

Alabama

Arrived 1943-9-1

Photo Gallery

Photograph of Alabama in profile
U.S. Navy
Photograph of Indiana
NARA
Photograph of main battery of Alabama
NARA
Photograph of 16" gun and radar antennas of Alabama
NARA
Photograph of flag bridge on Alabama
NARA
Photograph of boiler on Alabama
NARA
Photograph of South Dakota under construction
NARA
Photograph of skegs of South Dakota-class battleship
U.S. Navy


References

DANFS
Dullin and Garzke (1976)
Friedman (1985)

Gogin (2010)

Maas (1999)

Worth (2001)


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