Tone class cruiser

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Class overview
Tone class heavy cruiser
Name:	Tone
Preceded by:	Mogami-class cruiser
Succeeded by:	none
Completed:	2 ordered, 2 laid down, 2 commissioned
General characteristics
Type:	Heavy cruiser
Displacement:	11,213 (original)
Length:	189.1 meters
Beam:	19.4 meters
Draught:	6.2 meters
Propulsion:	4 shaft Gihon geared turbines 8 boilers 152,000 shp
Speed:	35 knots (67 km/h)
Range:	8,000 nautical miles at 18 knots
Armament:	8 × (203 mm) guns (4x2) 4 × 127 mm guns, 6 x 25 mm Type 96 AA guns 12 × 610 mm torpedo tubes (4x3)
Armour:	100 mm (belt) 35 mm (deck)
Aircraft carried:	6 x floatplanes, 1 catapult

The two Tone class cruisers (利根型装重巡洋艦, Tone-gata junjunyōkan^?) were the last heavy cruisers produced for the Imperial Japanese Navy. They participated in numerous actions during in World War II.

1 Background
2 Design
3 Modifications
4 Ships in class
5 References
- 5.1 Books
- 5.2 External links
6 See also

[edit] Background

The Tone class cruisers were originally envisaged as the 5th and 6th vessels in the Mogami class and were funded as such under the 2nd 1932 Supplementary Budget. However, by the time construction began, design weaknesses in the Mogami-class design had become clear after the Tomozuru Incident, and Japan no longer had any intention of even pretending to abide by the limitations of the London Naval Treaty. This resulted in a new design, which turned out to be quite different from the Mogami class, although external dimensions were very similar. These very vessels were intended to provide long-range air scouting for cruiser squadrons and to operate together with aircraft carrier task forces.

[edit] Design

[edit] Overview

The Tone class cruisers had a very distinctive silhouette, with all main armament concentrated forward and the aft section entirely devoted to aircraft operations. This allowed for strong and compact protection of the magazines while also increasing and improving the living quarters aft.

[edit] Armament

As originally planned, the Tone class vessels were to have five triple 152 mm turrets, three forward and two aft. However, the capsize of the torpedo boat Tomozuru called into question the stability of all Japanese warship designs. As a result of the redesign, and to improve accuracy of gunfire, all five turrets in the new design were concentrated on the forecastle. When Japan abrogated the Washington Naval Treaty on 31 December 1936, the main armament was revised to eight 203 mm guns in twin turrets with maximum 55 degree elevation, as was installed on the Mogami class vessels. No. 3 and No. 4 turrets trained through the after arcs, while No. 2 was pedestal mounted overlooking No.1 and No.3.

Heavy anti-aircraft weaponry consisted of four twin 127 mm gun turrets in shielded mountings amidships. For close-range, six twin 25mm Type 96 25 mm AT/AA Guns were carried. Four triple banks of 610 mm torpedo tubes were also incorporated.

[edit] Hull & Armor

The previous Mogami-class experimented with welded hulls, with limited success. Thus the lead vessel in the Tone-class, Tone, also had some welding, the subsequent Chikuma was an all riveted design. The undulating hull of earlier cruisers was dispensed with and the superstructure was less built-up. The modifications to the design raised the nominal displacement to about 12,500 tons. The main belt armor was 100 mm thick next to machinery spaces (125mm next to magazines), and it extended to a depth of about 9 feet, beyond which it had a much reduced thickness as an anti-torpedo bulkhead down to the inner double bottom.

[edit] Engines

The main engines of the Tone class were similar to that of the Suzuya and Kumano.

[edit] Aircraft

The Tone class had no aircraft hangar, but there was a comprehensive arrangement of transport rails and turntables on the aircraft catapult and quarterdecks. Two gunpowder-propelled catapults were located on the beam abaft the mainmast. A maximum of four Kawanishi E7K2 'Alf' three-seat floatplanes and four Nakajima E8N1 'Dave' floatplanes could be carried, the normal complement being six, of which four were to be E8Nls. In practice, no more than five were ever embarked. As the war progressed these types were superseded by the Aichi E13A1 'Jake' and Mitsubishi F1M2 'Pete'.

[edit] Modifications

In 1943, the number of 25 mm guns was increased to twenty guns, and in June 1944, when the opportunity to use their aircraft had passed, further mountings were added on the flight deck, bringing the light anti-aircraft total to 54 barrels. Two more twin 25 mm guns were also added later. Radar was fitted, but otherwise no major modifications were carried out.

[edit] Ships in class

Two ships were funded under the 1932 2nd Supplementary Budget, both of which were built by Mitsubishi at the Nagasaki shipyards.

Tone

Tone was part of the covering force for the attack on Pearl Harbor, and the following month it assisted in the second Battle of Wake Island. Subsequently, Tone was involved in operations in the Netherlands East Indies. In February 1942, it was part of the covering force for the carrier raid on Darwin, and in March accompanied the battleships Hiei and Kirishima in the sinking of the USS Edsall. During March Tone participated in the strike by Admiral Nagumo's carrier force into the Indian Ocean and the attack on Ceylon. Tone returned to the Pacific for the Battle of Midway in May, and from the summer of 1942 was part of the Guadalcanal campaign. On 2 August 1942, Tone was damaged by aircraft from USS Saratoga. In 1943, Tone patrolled in Solomon Islands theatre where it was damaged by an air raid on its base in Rabaul on 5 November. In the beginning of 1944, Tone participated in a strike into the Indian Ocean against Allied shipping on the Australia-Aden route. Later, Tone was in the Battle of the Philippine Sea, and as part of Admiral Kurita's Centre Force at the Battle of Leyte Gulf attacked US escort aircraft carriers. Tone was damaged by US aircraft in March 1945, after her return to home water and was finally sunk by aircraft, near Kure, on 24 July 1945. She was raised postwar and broken up at Kure in 1948.

Chikuma

The career of Chikuma parallels that of Tone in almost every detail, since both ships formed the 8th Cruiser Squadron on completion and operated together for almost all of their careers. In October 1942, during the Battle of Santa Cruz, Chikuma was hit by five bombs dropped by aircraft from USS Hornet. Chikuma was lost in the Battle off Samar on 25 October 1944.

[edit] References

[edit] Books

D'Albas, Andrieu (1965). Death of a Navy: Japanese Naval Action in World War II. Devin-Adair Pub. ISBN 0-8159-5302-X.
Dull, Paul S. (1978). A Battle History of the Imperial Japanese Navy, 1941-1945. Naval Institute Press. ISBN 0-87021-097-1.
Howarth, Stephen (1983). The Fighting Ships of the Rising Sun: The drama of the Imperial Japanese Navy, 1895-1945. Atheneum. ISBN 0-68911-402-8.
Jentsura, Hansgeorg (1976). Warships of the Imperial Japanese Navy, 1869-1945. Naval Institute Press. ISBN 0-87021-893-X.
Lacroix, Eric; Linton Wells (1997). Japanese Cruisers of the Pacific War. Naval Institute Press. ISBN 0-87021-311-3.
Whitley, M.J. (1995). Cruisers of World War Two: An International Encyclopedia. Naval Institute Press. ISBN 1-55750-141-6.