8 inch/55 Mark 9 (203 mm)

Description

Write an introduction to the article in 2-3 small paragraphs. Briefly tell us about the history of the development and combat using the weaponry and also about its features. Compile a list of air, ground, or naval vehicles that feature this weapon system in the game.

Vehicles equipped with this weapon

• USS Northampton
• USS Pensacola
• USS Portland

General info

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Available ammunition

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Penetration statistics
Ammunition	Type of warhead	Penetration @ 0° Angle of Attack (mm)
		1,000 m	2,500 m	5,000 m	7,500 m	10,000 m	15,000 m
Mk.14 Common	Common	116	102	83	69	57	43
Mk.19 APCBC	APCBC	383	339	277	228	190	143
Mk.25 HC	HE	61	61	61	61	61	61
Mk.17 SP Common	SP Common	137	121	99	81	68	51

Shell details
Ammunition	Type of warhead	Velocity (m/s)	Projectile mass (kg)	Fuse delay (s)	Fuse sensitivity (mm)	Explosive mass (TNT equivalent) (kg)	Ricochet
							0%	50%	100%
Mk.14 Common	Common	853	117.9	0.035	9	4.84	47°	60°	65°
Mk.19 APCBC	APCBC	853	117.9	0.035	9	1.62	48°	63°	71°
Mk.25 HC	HE	853	117.9	0	.1	9.5	79°	80°	81°
Mk.17 SP Common	SP Common	853	117.9	0.035	9	4.61	48°	63°	71°

Comparison with analogues

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Usage in battles

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Pros and cons

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Pros:

Cons:

History

After World War I, the victorious parties of the Entente Powers came to together to sign an agreement that would prevent another naval arms race like the dreadnought arms race that had preceded the Great War. As part of the negotiations, it was decided to divide cruisers between light and heavy cruisers based on the calibre of their guns. Heavy cruisers were defined as armed with 8 inch guns and a displacement of 10,000 tons, chosen to appease the British, American, and Japanese signatories who were all planning on cruisers with this calibre of guns. For the United States, their standard heavy cruiser armament became the 8 inch, fifty-five calibre guns, a built-up gun design that entered service in 1925. Weighing about 30 tons including a liner, tube, jacket, and five hoops, these guns had a down-swing Welin breech block closed by compressed air from the gas ejector system. The first ships built to mount these guns were the Lexington-class battlecruisers which had 4 twin gun turrets with the Mark 9 guns. However, the Washington Naval Treaty restrictions on constructing these types of ships led to their conversion to aircraft carriers and the cannons were repurposed as coastal defense guns on the Hawaiian Island of Oahu. Later in 1926, USS Pensacola and its sister ship Salt Lake City featured both two twin turrets and two triple turrets with the Mark 9. The following year, the Northampton and its class was built with 3 triple turrets with Mark 9 guns. In 1930, Portland and Indianapolis were built with 3 triple-turreted Mark 9s, and in 1931, the guns were fitted on the early New Orleans-class ships, the New Orleans, Minneapolis, and Astoria, before being replaced by the lighter 8 inch/55 Mark 12. The earlier ships armed with the Mark 9 would be refitted later in the war for the similar but superior 8 inch/55 Mark 14, except for Chicago, Houston, and Astoria which were sunk during the war, and Minneapolis which received the improved Mark 15 gun.

Media

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See also

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• reference to the article about the variant of the cannon/machine gun;
• references to approximate analogues by other nations and research trees.

External links

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• topic on the official game forum;
• other literature.