The Naval Gun Continues to Reign!

 

(Published SP’s Naval Forces Aug-Sept 2015)

A naval warship is a platform that is meant to last at least 25 years and have flexibility to upgrade its systems with changes in technology during this period. It would therefore be worthwhile to look at some of the formidable modern warships and their armament packages to get a perspective in to trends in the coming decades. Starting with the US Navy’s Littoral Combat Ship (LCS) the second LCS, Coronado has been designed for littoral warfare and is being equipped to tackle anti-submarine warfare, mine warfare and anti surface warfare. It is being outfitted with reconfigurable payloads called ‘mission packages’. The Coronado is being constructed by M/s Austal USA, in Alabama, USA. Apart from the mission modules, it carries Evolved SeaRAM (Raytheon) 11-cell missile launcher, 4 × .50-cal guns (2 aft, 2 forward) and 57 mm gun (Mk 110, of BAE Systems). The US Navy’s Zumwalt class guided missile destroyers have been designed as land attack, multi mission ships. These ships boast of an integrated power system, which can power rail gun or free electron laser guns of the future. The main armament consists of, 20 × MK 57 VLS modules (Raytheon) with a total of 80 launch cells, Tactical Tomahawk(Raytheon/ McDonnell Douglas) 1 per cell,RIM-162 Evolved Sea Sparrow Missile (ESSM-Raytheon) 4 per cell, Vertical Launch Anti-Submarine Rocket (ASROC- Lockheed Martin) 1 per cell, 2 × 155 mm/62 caliber Advanced Gun System (BAE), 920 × 155 mm rounds, 70–100 LRLAP rounds(Lockheed Martin), 2 × 30 mm Mk 46 Mod 2 Gun Weapon System (General Dynamics).

The Russian Navy’s Steregushchy class multipurpose corvettes are meant for littoral combat missions including those of anti submarine warfare, anti surface warfare and naval gunfire support. The armament package includes, 2 x 4 Uran Kh-35 (SS-N-25), 12 x Redut VLS cells, 1 x Kashtan CIWS-M, 2 x 4 330mm torpedo tubes for Paket-NK anti-torpedo/anti-submarine torpedoes, 2 × 14.5mm MTPU pedestal machine guns, 2 x AK-630М CIWS, and 1 x 100mm A-190 Arsenal or 130mm A-192 naval gun. The PLAN’s type 052D guided missile destroyer (Kunming class) is under construction at
Changxingdao-Jiangnan Shipyard (JNCX). The main armament consists of YJ-18 or YJ-83 anti-ship missiles, CJ-10 LACM, CY-5 series ASW missiles, 64 VLS, HHQ-9 series long range SAM, DK-10A medium range SAM, 1 x HHQ-10 short range SAM in 24-cell launcher, 6 torpedo tubes, 1 x H/PJ-12 CIWS, 2 x 30 mm remote controlled guns, and 1 x H/PJ-38 130mm dual purpose gun.

The Swedish Visby class corvettes have been designed by Swedish Defence Materiel Administration (FMV) and built by Kockums AB. They carry, 4 × 400 mm torpedo launchers for Type 45 (Saab) torpedoes, 8 × RBS15 Mk2 (Saab Bofors) AshM, and 1 × Bofors 57 mm Mk3. The Indian Navy’s project 15 B, Visakhapatnam class stealth guided missile destroyers, would carry, 4 × 8-cell VLS for a total of 32 Barak 8missiles, 2 × 8-cell Universal Vertical Launcher Module (UVLM) for 16 BrahMos anti-ship and land-attack missiles, 4 × 533 mm Torpedo tubes, 2 × RBU-6000 anti-submarine rocket launchers, 4 × AK-630 CIWS, 1 × 127 mm gun Oto Melara SRGM (likely).

Lastly, the Global Combat ship of the Royal Navy has been designed for 13000 km range at 15 knots with an endurance of 60 days. Its versatile design caters for anti piracy, anti terror, maritime security, and HADR missions. Its armament includes; 3 × 8-cell strike-length Mk 41 VLS (Martin Marietta/ Lockheed Martin) suitable for Tomahawk, ASROC and LRASM; 8 × 6-cell CAMM VLS (MBDA) canisters for a total of 48 CAMM (MBDA) missiles; Sting Ray torpedo system(GEC Marconi-likely); 2 × Phalanx (General Dynamics) CIWS; 2 × 30mm DS30M Mk2 (MSI Defence Systems) guns; 2 × Miniguns; 4 × General purpose machine guns; and 1 × BAE 5 inch Mk 45 naval gun.

The Naval Gun

The most striking thing about the armament packages of the formidable warships mentioned above is the fact that the Naval Gun continues to form an integral part of the firepower of these warships.

The Swedish Bofors 57 mm MK 3 gun is a dual-purpose naval gun designed and produced by AB Bofors. It has a rate of fire of 220 rounds per minute with a 40-round magazine within the turret. It features a new lightweight gun turret and a new gun barrel of   monobloc steel with a new servomechanism. This makes the gun respond rapidly and engage sea-skimming missiles with faster rate of firing. The Ammunition for the Bofors 57 mm gun is produced by Bofors, Sako Limited in Finland, and Nammo in Norway. BAE Systems AB also offers the Bofors 57 mm 3P all-target programmable ammunition, this allows three proximity fusing modes as well as settings for time, impact, and armor piercing functions. It has the flexibility to choose ammunition mode at the time of firing. Further, it has the ability to engage ground, air, and surface targets. This year BAE has announced a new round the Mk 295 Mod 1 Ordnance for Rapid Kill of Attack Craft (ORKA) with single shot kills of air and surface targets.

The Russian AK-130 is a twin-barreled gun with a rate of fire of 20-86 rounds per minute and a range of over 20 km. PLAN’s  H/PJ38 is a single barrel 130 mm gun. It is copied from the Soviet AK-130 and is considered more reliable and powerful than the original. The Chinese carried out the crucial improvement of adapting the gun to fire both separate and semi-fixed rounds. China has also developed a variety of sub-caliber rounds for the H/P J38.

The BAE Systems AGS & MK45 Mod 4 127/62, the Oto Melara 127/64 gun & the 76mm Super Rapido continue to be the most advanced guns today.

BAE’s Advanced Gun System, AGS, is designed for delivering precision munitions at a high rate of fire and at over-the-horizon ranges. It includes an automated magazine, the ammunition uses a separate propellant canister for both conventional and guided munitions. Projectiles include ballistic projectiles as well as guided land & surface attack munitions using course correcting fuses (CCF). The rate of fire of Long Range Land Attack Projectiles, LRLAP is 10 rounds per minute.

BAE Systems Mk 45 Mod 4 is 5-inch (127-mm) 62-caliber gun mount used in the U.S. Navy . The enhanced gun system has significantly improved capabilities for Naval Surface Fire Support (NSFS), as well as overall gunfire mission performance. Upgrades have been carried out, which enable Mk 45 to handle and fire high-energy munitions. It also optimizes performance of new and existing ammunition types. As per BAE, firepower flexibility of the Mk 45 Mod 4 naval gun system is achieved with the combination of several features such as, Multi-mission ammunition inventory, mixed ammunition load capacity, Remote round-to-round selectivity, and  advanced fire control adaptability.

The Oto Melara 127/64 Lightweight Vulcano constitutes;  the large caliber 127/64 LW Gun assembly,  the Automated Ammunition Handling System, the Naval Fire Control Support, and  the VULCANO  family  of ammunition. It is a medium caliber naval gun meant for surface fire and naval gunfire support as its main role and anti-aircraft fire as its secondary role. The compactness of the gun feeding system makes it possible to install it on medium size warships also.  It has a modular automatic feeding magazine with four rotating drums, each holding 14 ready-to-fire rounds. It is thus able to fire 30/35 rounds per minute. The Fire Control System calculates the ballistic trajectories, programs the fuses and, it updates GPS data when the GPS-guided VULCANO rounds are fired.

Status of Ammunition Development

In addition to the standard round the 127 mm Oto Melara can fire the VULCANO, which is a steerable sub-munition with tail fins and canards. The VULCANO range comprises of; the BER (Ballistic Extended Range) with a range of 70 km;         GPS / Inertial Navigation System;   GPS / INS / Infra-red Imaging; and GPS / INS / Semi Active Laser (SAL).

The GPS/INS ammunition is used against fixed targets, with high accuracy. In case of the GPS/INS/SAL round, Diehl provides the miniaturized, shock-resistant Semi-Active Laser seeker and Oto Melara supplies the projectile. The SAL guides the shell to engage small, fixed, moving, and re-locatable targets with very high accuracy. The addition of a SAL seeker to the GPS and inertial navigation guidance makes this variant of the round extremely accurate. With external laser designation of the target, it can even engage moving targets with high accuracy. The IIR seeker is used for anti-ship role. The built-in IIR seeker scans the surface of the sea to detect and track the heat signature of the enemy vessel a few miles before entering the target zone. On acquiring the target, it can maneuver to counter evasive measures if any. The 4AP (4 Action Plus) fuse of the Vulcano is a microwave fuse, which can detonate on impact, time, airburst, or proximity. The development of the BER variant has been completed. The guided variants, are more or less in their final leg  of the development phase.

BAE’s Standard Guided Projectile – Multi Service is a 127mm shell with GPS/INS guidance, propelled by a rocket booster. It has an in flight retargeting feature which is enabled by GPS feed to the shell. This enables it to engage even small moving targets. It has a range of up to 100 km with a CEP better than 10 m. It has a 16.3 kg warhead.

Oto Melara’s ‘Strales’ for its 76.2 Super Rapido Gun is a guidance kit, having a radio frequency beam antenna for use when firing the DART (Driven Ammunition Reduced Time of flight). It is a guided, sabot-discarding high speed round meant to engage airplanes, missiles and fast attack crafts. The DART comprises of a 2.5 Kg pre fragmentation tungsten cube warhead located in the rear, whereas the front portion is free to rotate with two canard wings. The tail has backward looking radio receivers and six fixed wings for line of sight guidance. It has the 3A PLUS programmable fuse. The DART can fly 5 km in 5 seconds. The development of STRALES kit has already been completed and it has been installed on the Italian aircraft carrier Cavour. Oto Melara has also developed  the Stealth gun shield, made of carbon fiber, with foldable gun barrel and sliding cover. It would be fitted on the new FALAJ-class corvettes of the UAE.

Ongoing Research

Composite Gun Barrel.       Texas Research Institute Austin, Inc. is researching in to the requirements of US Navy for a low-cost, lightweight, composite outer wrapped rifled barrel design suitable for firing high-energy projectiles from the Zumwalt destroyer advanced gun system. The rapid firing of high-energy projectiles using high-temperature propellants causes high dynamic barrel pressurization loads, rapid heating of the barrel, and increased fatigue & wear on the barrel bore. The US Navy requires a composite outer wrapped actively water-cooled barrel design using high-performance composite materials to provide a gun barrel with superior dynamic strength, fatigue, wear, and heat dissipation characteristics. Texas Research Institute Austin, Inc., is developing a polymer composite filament-wound outer wrapped gun barrel design that will meet requirements of the advanced gun system. Use will be made of developments of lightweight, high-temperature, fatigue-resistant, filament-wound composite applications in the offshore oil and gas, marine, automotive, and aircraft industries.

Development of Materials and Processes That Eliminate Large Gun Barrel Wear & Erosion from Advanced Propellants & Projectiles.        Materials & Electrochemical Research, Tuson, have  demonstrated that molybdenum-rhenium (Mo-Re) alloys exhibited negligible erosion and wear in terms of weight loss, as compared to chromium plated gun steel. Research is now being carried out to optimize the Mo-Re ratio versus vented bomb erosion and wear, followed by mechanical property characterization including fatigue life.

Conclusion

It is apparent that the shipbuilders and war planners have decided that no warship should be without the Naval Gun ! This is due to the compelling reasons that; guns can engage various targets like air, surface, land and FAC; they act as a contingency to missile systems; guns have short reaction time, and can engage selected land targets; they practically operate in most weather conditions; they have a sustained bearing on targets, they are not prone to jamming; and  they can engage a number of low flying missiles due to absence of dead zones.

Further the reason for the naval gun to remain relevant in the modern warships despite the missiles lies in the advent of long-range precision guided ammunition. Micro-miniaturization of guidance electronics and developments in gun propellants, has ensured very high accuracy of rounds at extended ranges and at costs, which were unthinkable a decade ago. The development of the precision guided ammunition implies that targets can be selectively engaged with great accuracy, maneuvering targets can be attacked, quick reaction times are available, and costs of engagement can be substantially reduced. Thus for the next two decades it appears that the naval gun would continue to be a major component of a warship’s outfit.

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