Britain 155 mm/52 Future Naval Gun

Britain
155 mm (6.1") Future Naval Gun and Alternatives
Updated 21 January 2011

The UK Ministry of Defense (MOD), DERA and RO Defence have performed studies over the past few years to assess future naval fire support requirements, particularly for the new Type 45 destroyers. Work was originally focused on developing a new 155 mm/52 "Future Naval Gun" which could take advantage of standard NATO 155 mm ammunition and the extended-range guided munitions already in development for land-based 155 mm artillery. However, MOD was unable to fund the high development cost associated with developing a new 155 mm naval mounting, and in regards to the Type 45 destroyer, there were concerns that the very large magazine required would use up the volume reserved for the 16 extra VLS cells for deep strike missiles. As of December 2007, at least the first six Type 45 ships will mount the 4.5" (114 mm) Mark 8 Mod 1 gun and it seems unlikely that follow-on units as commissioned would use any other gun mounting.

In mid-2004, competition for arming the Type 45 came from United Defense, who proposed their 5"/62 (127 mm) Mark 45 Mod 4 for these ships. As part of this proposal, United Defense would sub-contract much of the assembly work to British firms, similar to what they have done for other nations. This United Defense proposal was rejected by the Royal Navy in early 2005 as being too expensive. The acquistion of United Defense by BAE Systems in June 2005 has made any competition between BAE and United Defense moot.

In response to the United Defense proposal, in December 2004 BAE Systems made a proposal to use the existing gun house for the 4.5" (114 mm) Mark 8 Mod 1, but use the same 155 mm/39 gun barrel being used on the Army's AS90 Braveheart self-propelled howitzer. BAE called this proposal the 155 mm TMF (Third generation Maritime Fire support). BAE claims that this arrangement would not create recoil forces beyond the capability of the Mod 1 mounting and estimates that this design would weigh 24.5 tons compared with 22.5 tons for the 4.5" (114 mm) Mark 8 Mod 1 and 26.4 tons for the original Mod 0. BAE foresees that the largest modification would be changing to a double-stroke loading cycle needed to handle modular charges. BAE estimates that this change would reduce the rate of fire to about 12 rounds per minute. There would also need to be a modification of the gun shield to allow for higher elevation angles.

BAE states that the Mark 8 Mod 1 gunhouse could also be used for a Fourth generation Maritime Fire support weapon (FMF) using the longer-barrel 155 mm/52, but this combination would require strengthening of the gunhouse in order to meet the added recoil forces.

MOD awarded BAE a research contract in 2007 to pursue their TMF design. However, the project was cancelled in late 2010 as part of large UK budget cuts in defense and other areas.

Mockup of BAE Systems 155 mm/39 TMF
Photograph copyrighted by BAE Systems

Comparison of 114 mm vs. 155 mm gun barrels
Photograph copyrighted by BAE Systems

Sketch of TMF Ammunition Feed Ring
Unlike other separate ammunition ready service rings, the TMF stores cartridge cases and projectiles side by side. This has the advantage of lower height at a cost of fewer rounds of ammunition in the ring.
Sketch copyrighted by BAE Systems

Gun Characteristics .

Designation	155 mm (6.1") Future Naval Gun
Ship Class Used On	Planned for Type 45
Date Of Design	2002-2005 for various proposals
Date In Service	2010 (?)
Gun Weight	BAE TMF: 5,765 lbs (2,615 kg) 52 caliber guns: N/A
Gun Length oa	BAE TMF: 279.2 in (7.092 m) 52 caliber guns: N/A
Bore Length	BAE TMF: 238.0 in (6.045 m) 52 caliber guns: N/A
Rifling Length	N/A
Grooves	BAE TMF: 48 52 caliber guns: N/A
Lands	N/A
Twist	BAE TMF: Uniform RH 1 in 20 52 caliber guns: N/A
Chamber Volume	BAE TMF: 1,150 in³ (18.84 dm³) 52 caliber guns: N/A
Rate Of Fire (see Note)	Requirement: about 20 rounds per minute BAE TMF Proposal: about 12 rounds per minute
Note: A key design goal for this weapon is that it be able to use standard NATO modular charges. However, the development of charge-handling technology able to achieve the required rate of fire shown above is seen as a major challenge, as land-based systems using these charges have rates of fire well under 10 rounds per minute. Almost all current naval gun systems use single-piece cartridges with less complex handling requirements in order to achieve higher rates of fire.

Ammunition .

Type (see Note 1)	Modular
Projectile Types and Weights (see Note 2)	HE - 98 lbs. (44.5 kg)
Bursting Charge	N/A
Projectile Length	N/A
Propellant Charge	N/A
Muzzle Velocity	L15A1 projectile and eight modular charges BAE TMF: 2,713 fps (827 mps) 52 caliber guns: about 3,100 fps (945 mps)
Working Pressure	L15A1 projectile with eight modular charges BAE TMF: 18.5 tons/in² (2,860 kg/cm²) 52 caliber guns: N/A
Approximate Barrel Life	N/A
Ammunition stowage per gun	N/A 8 complete rounds in ready service ring
Notes: 1) As noted above, a key requirement for this program is that it be able to use standard 155 mm modular charges. This would allow a common munition program for both land and naval systems using this size caliber and thus reduce both development and service costs. 2) Standard NATO of 155 mm ammunition includes high-explosive projectiles, bomblets, smoke and illuminating rounds. Future developments include smart and cargo rounds, such as those already in service in the US Army.

Range .

Elevation	With 98 lbs. (45.5 kg) Shell
Range @ 45 degrees	about 40,000 yards (36,500 m)
.	With rocket-assisted shell
N/A	about 76,000 yards (70,000 m)
	For TMF with L15 Projectile and 8 Charges
Range @ 45 degrees	26,250 yards (24,000 m)

Mount / Turret Data .

Designation	N/A
Weight	Future Naval 155 mm/52 Gun Mount about 44,100 lbs. (20,000 kg) Hoist System: about 7,710 lbs. (3,500 kg) BAE 155 mm/39 TMF about 24.5 tons BAE 155 mm/52 FMF about 26 tons
Elevation	-15 / +80 degrees
Elevation Rate	N/A
Train	N/A
Train Rate	N/A
Gun recoil	N/A
Notes: 1) Whichever mounting is selected, it is required that it be able to replace the 4.5" (11.4 cm) Mark 8 Mod 1 mountings used on existing Type 45 destroyers without requiring major modifications. 2) Gun crew for any of these weapons is estimated at 1 gun captain, 1 gun bay attendant and 3 or 4 magazine handlers.

Data from
BAE Systems Press Releases
"The Naval Institute Guide to World Naval Weapon Systems: 1994 Update" by Norman Friedman
"Defense & Armament Heracles International" Issue #87, September 1989
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"155mm Third Generation Maritime Fire Support (TMF)" by Robert McClure of BAE, presented at the NDIA 44th Annual Gun & Ammunition Symposium & Exhibition

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Naval Forum UK
"Bigger is Better" post of 14 December 2007 by Douglas Barrie at Aviation Week website
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Special help from Matthew Rodchenko

Page History

14 August 2008 - Benchmark
31 May 2010 - Added link to 155mm Third Generation Maritime Fire Support (TMF)
21 January 2011 - Project cancellation