Nagato class battleship

The battleship Nagato
Class overview
Name:	Nagato
Operators:	Imperial Japanese Navy
Preceded by:	Ise-class battleship
Succeeded by:	Tosa-class battleship
In service:	– 1945
In commission:	November 15, 1920
Completed:	2
Active:	none
General characteristics
Type:	Battleship
Displacement:	32,720 tons (standard load) 42,850 tons (full load wartime)
Length:	221.03 m (725 ft 2 in) 215.79m (708 ft) at launch
Beam:	34.59 m (113 ft 6 in) 29m (95 ft) at launch
Draught:	9.50 m (31 ft 2 in)
Draft:	2.9 metres
Propulsion:	Geared turbines, 4 shafts, 80000 hp (60 MW)
Speed:	27 knots (50 km/h)
Range:	6,815 mi (5,922 nmi) at 16 kn (18 mph; 30 km/h) Fuel: 4500 tons
Complement:	1,368
Armament:	8 × 16.1 inch (410 mm) guns 20 (later 18) × 5.5 inch (140 mm) guns 8 × 5 inch (127 mm) anti-aircraft guns Up to 98 × 25 mm AA guns
Armor:	deck: 2.8+3.0 in (70+76 mm) face & side of turrets: 12 in (305 mm) ceil of turrets: 6 in (152 mm) belt: 12+inclined 3 in (305+inclined 76 mm) after refit: deck(ammo strage): 2.8+5.0+2.0 in (70+127+51 mm) deck(engine room): 2.0+2.8+1.0 in (51+70+25 mm) deck(other parts): 2.5+3.0 in (70+76 mm) face of turrets: 20 in (508 mm) side of turrets: 14 in (356 mm) ceil of turrets: 9–10 in (229–254 mm) belt(ammo strage): 12+inclined 8–14 in (305+inclined 203–356 mm) belt(other parts): 12+inclined 3 in (305+inclined 76 mm)
Aircraft carried:	3

The Nagato-class battleships (長門型戦艦, Nagato-gata senkan^?) were two battleships (Nagato and Mutsu) of the Imperial Japanese Navy. The name Nagato (Japanese: 長門) comes from the Nagato province. They were the first battleships to be built entirely in Japan. They were the first battleships in the world to mount 16 inch (410 mm) guns and were considered as the Japanese navy equivalents of the British Navy’s 'Queen Elizabeth' class battleships. At the time of their completion in 1920–21, their armament, armor, and speed made them the most powerful capital ships in the world.

The ships were extensively modified in the 1920s and 1930s after the Washington Naval Treaty of 1922 limited the battleship tonnage of the Japanese (and other) navies and allowed no new construction for several years. As a result of the treaty, they were the last battleships built by Japan until the Yamato class battleships of the late 1930s.

It was not until 1937 that the US Navy became aware that their actual speed was considerably higher than the 23 knots they had previously assumed, which resulted in a redesign of the 'South Dakota' battleship class to provide them with a higher speed.^[1]

Design

Overview

Right elevation and deck plan as depicted in Brassey's naval annual 1923

Right elevation and deck plan, c. 1936

Authorised in 1917, and allocated the design number A-102^[1], the class was designed by Captain Yuzuru Hiraga. The design was completed in the spring of 1916. The Nagato class was based on the hull design of the Ise-class with a main armament of eight 16-inch guns instead of twelve 14-inch while retaining a similar broadside weight.

Armament

The decision in favour of 16-inch guns was made by the Naval Minister Admiral Tomosaburo Kato.^[1] The 16-inch guns had an actual bore diameter of 16.14-inch (41 cm) and were originally designated as 41 cm/45 3rd Year Type. In March 1922 they were redesignated as 40 cm/45 3rd Year Type. The guns were designed for use in not only the Nagato class but also the later cancelled Kaga, Amagi and Kii classes of the early 1920s.^[2]The main armament was located in four twin superimposed turrets aligned along the centreline. In general arrangement and in most details, the turrets were similar to the British 15-inch turrets, but with a number of improvements including better flash tightness in the turrets. They also featured longitudinal flash-tight bulkheads between the guns, and between the gun loading hoists in the area where shells and charges were transferred from lower to upper hoists. The principal secondary armament of twenty 5.5 inch (140 mm) guns was located in casemates along the side. They also had eight 533 mm torpedo tubes, four of which were underwater.

Mast

The Nagato class was equipped with the heptapodal (7-legged) mast, unique to Japanese ships, designed to maximize rigidity for range finding purposes and survivability under shellfire. These masts consisted of one thick vertical leg in the centre with two legs which sloped forward, two sloping backwards and one to either side. The central vertical leg was large enough to accommodate an electric lift running between the foretop and main deck.^[3]

Armor

The armour arrangement resembled the American "All or Nothing" where the construction was designed to ensure the vital components of the ship were surrounded by thick armour while non-vital parts of the ship were unprotected. Previous Japanese practice was not to use side armour above the main armour belt. Compared with American "All or Nothing" practice the Nagato class included considerable armour on the lower deck, which in American practice was only a light splinter deck. The upper end of the torpedo bulkhead was sloped upwards to meet the downward sloping armour deck, to completely enclose the vital components. This armour design was later incorporated into all future Japanese capital ships. Another unusual feature was an upper armoured deck over the lower secondary armament.

Reconstruction

Line drawing of Nagato as she appeared in 1944

Armouring scheme, illustrated together with the improved torpedo defenses

From 1934 to 1936, both Nagato-class ships were reconstructed to be similar to the Fuso and Ise classes. The stern was extended to a length of 737 feet, anti-torpedo bulges increased their beam from 95 to 113 feet and 6 inches, a triple bottom was installed, two 5.5 inch guns and the 3 inch anti-aircraft guns replaced with four twin 5-inch anti-air turrets and ten twin 25mm mounts, and 21 mixing boilers were replaced with 10 oil-fired boilers^[4]

Service

Nagato

Nagato in 1939, after her reconstruction

At the outbreak of World War II, Nagato was under the command of Captain Yano Hideo. She and her sister ship Mutsu formed Battle Division 1. Nagato was also the flagship of Admiral Isoroku Yamamoto. On 2 December 1941 Nagato sent the signal Niitakayama nobore 1208 "Climb Mount Niitaka on 12/08 (Japanese Time)". That message committed the Carrier Strike Force to the attack on Pearl Harbor and Japan to the Pacific War. Nagato's second assignment was to the Japanese Battleship Division 1 of the First Fleet under the command of Rear Admiral Gihachi Takayanagi. There, along with Mutsu and Yamato, she was present at the Battle of Midway. She did not see any action there, but helped return survivors of the Kaga, a carrier which had been fatally damaged by SBD Dauntless dive bombers from USS Enterprise, to Japan. After that, Nagato was stationed at Truk and Lingga. Nagato participated in both Operation A-Go, an attack on Allied forces in the Mariana Islands and in the Battle of the Philippine Sea, where she came under air attack but was not damaged. In October 1944, Nagato took part in Operation Shō-1, an attack on the Allied landings on Leyte. In the Battle of the Sibuyan Sea Nagato was attacked by several waves of American dive-bombers, which disabled a number of guns, damaged the air intake to the No. 1 boiler room, killed 52 and wounded 106. On 25 October the Central Force (including battleships Yamato, Nagato, Kongō, and Haruna) passed the San Bernardino Strait and headed for Leyte Gulf. In the battle off Samar, Nagato engaged the escort carriers and destroyers of the US Task Group 77.4.3. Early in the engagement, she opened fire on St. Lo, the first time she fired her guns at an enemy ship, but missed. At 06:54 the destroyer Heermann fired a spread of torpedoes at Haruna, but the torpedoes missed Haruna and headed for Yamato and Nagato on parallel courses. The two battleships were forced to turn away from the action to the north for 10 miles (16 km) until the torpedoes ran out of fuel. She was the only Japanese battleship to survive World War II and was expended in the US Operation Crossroads atomic bomb tests in 1946. A life-size replica of her was made for the film Tora! Tora! Tora!.

Mutsu

A gun from the Mutsu on display at the Yamato Museum in Kure, Japan

The Mutsu, commissioned into the Japanese Battle Division 1, was also in Isoroku Yamamoto's Main Body during the Battle of Midway. She was sunk by an internal explosion on June 8, 1943, which was ruled by the Japanese Government as "human interference".^[5]

Ships of the class

Name	Laid Down	Commissioned	Fate
Nagato(長門)	August 28, 1917	November 15, 1920	Sunk during the second Operation Crossroads "Baker", Bikini atoll nuclear test, 25 July 1946
Mutsu(陸奥)	June 1, 1918	October 24, 1921	Sunk by internal explosion, June 8, 1943

See also

• Queen Elizabeth-class battleship — Approximate British equivalent
• Colorado-class battleship — Approximate American equivalent

References

1. ^ ^{a b c} Sturton. Page 164.
2. ^ http://www.navweaps.com/Weapons/WNJAP_161-45_3ns.htm. Retrieved 22 April 2010
3. ^ Gardiner, Gray & Budzbon. Page 231.
4. ^ Ireland, Bernard (1996). Jane's Battleships of the 20th Century. London: Harper Collins. pp. 76–77. ISBN 0-00-470997-7. 
5. ^ Spector, Ronald (2001). At War at Sea: Sailors and Naval Combat in the Twentieth Century. Penguin Group. ISBN 0 14 02 4601. 

• D., Tony. "Japan 41 cm/45 (16.1") 3rd Year Type 40 cm/45 (16.1") 3rd Year Type ." 19 April 2007 1. Web.7 Aug 2009. <http://www.navweaps.com/Weapons/WNJAP_161-45_3ns.htm>.
• Tully, Tony. "Nagato-class Battleship." Web.7 Aug 2009. <http://combinedfleet.com/ship.php?q=nagato_c.htm>.
• Tully, Tony. "IJN MUTSU: Tabular Record of Movement." 2000 Web.7 Aug 2009. <http://combinedfleet.com/Mutsu.htm>.
• Tully, Tony. "IJN NAGATO: Tabular Record of Movement." 2000 Web.7 Aug 2009. <http://combinedfleet.com/nagatrom.htm>.
• Chen, C. Peter. "Nagato-Class Battleship." WW2 Data Base 2004 Web.7 Aug 2009. <http://ww2db.com/ship_spec.php?ship_id=B466>.

Further reading

• Gardiner, Robert; Gray, Randal; Budzbon, Przemysław (1985). Conway's All the world's fighting ships, 1906–1921. London: Conway Maritime Press. pp. 416 pages. ISBN 0851772455. 
• Williams, Mike (2009). Jordan, John. ed. Mutsu – An Exploration of the Circumstances Surrounding her Loss. Warship 2009. London: Conway. pp. 125–142. ISBN 978-1-84486-089-0. 
• Sturton, Eric, ed (2008). Conway's Battleships. London: Conway Maritime Press. pp. 240 pages. ISBN 978-1-59114-132-7. 

External links