Tosa class
| Tosa class | |
|---|---|
|
|
| Overview | |
| Type: | Battleship |
| Units: | (2) |
| Predecessor class: | Nagato class |
| Successor class: | Yamato class |
| Technical data (original planning) |
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| Displacement: | Standard: 39,900 t |
| Length: | over everything: 230.1 m |
| Width: | 30.5 m |
| Draft: | 9.4 m |
| Speed: | Peak: 26.5 kn |
| Crew: | about 1300 permanent crew |
| Range: | - |
| Drive: | 4 screws over 4 shafts |
The Tosa class ( Japanese 土 佐 型 戦 艦 , Tosa-gata senkan ) was a class of battleships of the Japanese Empire , of which two ships were planned.
The two planned ships were laid on the keel and the construction advanced to different stages of completion. According to the provisions of the Washington Treaty (Washington Fleet Agreement), however, they are intended to be scrapped. One of the ships was actually demolished and the other converted into an aircraft carrier.
Development history
The decision to lay another class of battleships on the keel arose from the so-called "8-8 plan" of the Navy, which had the goal of having a fleet of eight battleships and eight battle cruisers in active service. Four battleships were already in place and two more under construction when planning for the Tosa class began.
With a short time lag to the previous class and planned by the same development team, the Tosa class did not differ that much from the Nagato class . The most obvious difference was an additional turret for the main artillery, while the armor concept and propulsion systems of the previous class were largely retained.
Washington Fleet Conference
The results of the Washington Naval Conference from November 1921 to February 1922 essentially revolved around the idea of freezing the navies of the participating powers' navies on the stock of ships that were in active service at the beginning of the conference. Therefore, the demand went to Japan to scrap the battleship Mutsu and the two ships of the Tosa class . The work on the other units, such as the battlecruisers of the Amagi and the battleships of the Kii class , should be canceled or not started at all.
While the Mutsu could be saved in tough negotiations and the Amagi class could be kept under the condition that both ships were converted into aircraft carriers, the Tosa class had to be scrapped.
Propulsion systems
The drive systems are made up of twelve boilers that supply the steam to operate four Brown Curtiss steam turbines . These turbines transferred around 91,000 SHP to four propellers. That should be enough for a speed of up to 26.5 knots .
Armament
Main artillery
The main artillery was to consist of ten 16 inch L / 45 guns , which were to be placed in five twin turrets along the longitudinal axis of the ships. Tower “B” and tower “D” were to be positioned elevated, while the additional tower “C” was seated on the weather deck and accordingly had a limited field of fire, forward through the superstructure and aft through the barbed of tower “D” .
Secondary artillery
Twenty 14 cm L / 50 guns were to be installed in casemates as secondary armament. As with the previous Nagato class , the ten guns on each side of the ship were to be distributed over two decks. While the installation of six guns was planned in the uppermost deck of the hull, four more should be installed in the superstructure above.
Air defense
Four individual 7.62 cm L / 40 anti-aircraft guns, officially classified as 8.0 cm, were to be placed in open mounts on deck.
Torpedoes
The eight 61 cm torpedo tubes were installed in the foredeck, directly in front of tower “A”, in the hull. The torpedo room was one deck above the waterline, the torpedo store was one deck lower. The basic idea of these rooms was that the battleships could be involved in long-lasting skirmishes with other battleships, in which both opponents ran on parallel courses for a long time , so that it would have been possible to shoot the enemy with torpedoes .
Armor
Structural protection
The Tosa class received an integrated, structural protection system without additional torpedo bulges. The system was similar to the concept originally used in the previous class: an outer shell made of comparatively thin steel, an expansion space with tanks that contained air or fuel, a 75 millimeter thick torpedo bulkhead and behind it another layer with tanks that was connected by a longitudinal bulkhead of the engine rooms and magazines were separated. In order to minimize the effects of splinters and pressure waves that could develop on the underwater hull during explosions, the structural protection was reinforced amidships, at the level of the engine rooms, by means of crush tubes, which were used to fill one of the compartments in front of the torpedo bulkhead. Crumple tubes made it possible to reduce the thickness of the subsequent armor in these areas by up to 30 percent without reducing the protective effect.
Armor protection
The Tosa-class vertical belt armor was 280 millimeters thick at its strongest point. In contrast to the previous class, in which it was installed vertically, it tilted inwards from the upper deck by around 15 degrees and reached approximately to the upper edge of the torpedo bulkhead.
The horizontal protection consisted of an armored deck 100 millimeters thick and an intermediate deck around 38 millimeters thick.
The barbeds , i.e. the cylindrical structures below the towers through which the ammunition was transported, were protected all the way to the armored deck with up to 230 millimeters of armor steel, which in some places grew up to 300 millimeters thick.
The command post, i.e. the small command center in the bridge tower, directly behind tower "B", from which the most important ship systems could be controlled in an emergency, was to be protected by 360 millimeters of steel.
Tosa class ships
Tosa
The Tosa was laid down by the Mitsubishi shipyard in Nagasaki in February 1920 and launched in December 1921. After construction stopped in February 1922, its completion was stopped. Parts of the equipment, such as the towers, went to other ships. After lengthy preparations, the hull of the Tosa was subjected to a series of scientific bombardment tests in which various torpedo and mine warheads were tested on the ship. Based on the results, naval battleships and cruisers were converted to optimize their armor protection. The armor concept of the super battleships of the Yamato class was also based on the experience gained from these tests. The worn out Hulk was sunk in the waterway between Kyūshū and Shikoku in 1925 .
Kaga
The Kaga was laid down in July 1920 by the Kawasaki shipyard in Kobe and was launched in November 1921. After construction stopped in February 1922, it was removed from the equipment to be scrapped. Since one of the Amagi-class battlecruisers , which were to be converted into aircraft carriers, was badly damaged in an earthquake in 1923, the Kaga took its place and went back to the shipyard for conversion. It became one of the key units in the Japanese aircraft carrier fleet, and its planes took part in the attack on Pearl Harbor in December 1941 . After numerous missions in the Pacific War , it was finally attacked by American carrier aircraft on June 4, 1942 at the Battle of Midway and subsequently so badly damaged by fires and secondary explosions that it had to be abandoned.
Evidence and references
Individual evidence
- ↑ Mark Sullivan, Joseph Cummings Chase: The Great Adventure at Washington, the Story of the Conference. Bibliolife, 2009, ISBN 1-115-52616-2
literature
Sources on the Tosa class:
- Roger Chesneau and Robert Gardiner: Conway's All the World's Fighting Ships 1922-1946. US Naval Institute Press, 1980, ISBN 0-87021-913-8
- Reports of the US Naval Technical Mission to Japan, Series S, S-01-9 "Underwater protection".
Sources on the political situation and planning of the Japanese Navy:
- David C. Evans: Kaigun: Strategy, Tactics, and Technology in the Imperial Japanese Navy 1887-1941. US Naval Institute Press, 2003, ISBN 0-87021-192-7
