47. Resurgence of the Naval Gun

(Published in Defence and Security of India; Feb 2015)

“Without a decisive naval force we can do nothing definitive, and with it, everything honorable and glorious.”
President George Washington

Blue water navies across the world are reassessing their capabilities to meet the demands of littoral warfare. The shallow waters harbor threats like small submarines, mines, hostile boat swarms, shore based aircrafts/UAVs, gun batteries and missiles. The Navies have to focus on tackling challenges emanating from shores before getting unfettered access to coastal areas of interest. Neutralizing swarms of small hostile craft in littorals due to their intermingling with local fishing craft in restricted maneuverability and short reaction times pose a formidable problem to Navies designed for standoff operations. Scenario and simulation studies have established that most of the NATO frigates are vulnerable to an attacking swarm of four to eight such small hostile craft. The small hostile craft’s weapons of choice include hand held weapons (the PK / RPK 7.62 mm, the NSV 12.7 mm, the Rheinmetall MG 3, the AK 47, AK 74, the FN FAL, the H&K G3 etc), and rockets launchers like the RPG-7.
Navies are modernizing the main & auxiliary gun and Close in weapon system CIWS out fits because various studies have brought out that ships using a mix of sophisticated high and low caliber weapons with high probability of hits, have much greater chance of survivability then those with semiautomatic systems. Navies are upgrading both the ordnance and the software. The goal is to achieve very high hit probabilities with high firing rates.
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Further, Studies carried out in the US to meet the requirements of the US marines, have concluded that; naval surface fire support NSFS had been crucial during the past operations. Larger caliber guns provide support at much longer ranges and are essential for destroying fortified positions. With the advent of Precision Guidance in larger caliber rounds, collateral damage has been considerably reduced. Their penetration ability in case of hard targets is practically as good as ordnance delivered by air. In order to achieve similar effects in suppressing the enemy, using smaller caliber guns like the MK 45 (5 inch), much greater number of rounds would have to be fired. During protracted war, the large caliber gun outshines the missiles because of high replacement costs of the missiles. It has a definite edge over the smaller caliber guns as the smaller caliber rounds have much lesser lethality. Both missiles and smaller caliber gun ammunition also require a large quantity to be stored on-board. The Air support operations in high threat environments are hindered by availability, mission priorities, weather, as well as prohibitive costs. All these make the large caliber gun a very cost beneficial solution in Naval Surface Fire Support (NSFS) missions.
Thus, it can be seen that the Naval Gun is likely to continue for a much longer period than previously anticipated. Conventionally the gun outfits of naval ships have included a heavy gun (57 mm caliber up wards), an auxiliary gun of up to 35 mm caliber, and a small caliber gun for close air/ missile defense. The number of turrets has depended upon the size and the role of the ship. Some of the heavy naval guns are, AGS 155, OTO Breda 127/54, OTO Melara 127/64, OTO Melara 76 mm gun (traditional /compatto/rapid), Bofors 57/70 mm MKII / MKIII, CADAM Turret / Loire 100mm / MK55 Mod 68, and Giat CADAM Turret. Examples of auxiliary guns are, Rheinmetall GDM-08 with MSP 500, Rheinmetall RH 202,OTO Breda 40/L70 twin, Mauser EADS MLG 30/27 mm, Allied Telesyn DS 30M Automated Small Caliber Gun System and Oerlikon Gam/BO1. Some of the CIWS are, Raytheon / Diehl RIM 116 Block 1 HAS, Signaal GAU-8/A, GE / GDC MK 15 Mod 2, and Mauser Oerlikon MeRoKa. However, the inability of these guns to rapidly train, elevate, or depress to prosecute swarming targets from different directions at close quarters has resulted in their poor effectiveness in littoral warfare. Navies are therefore opting for modernized or new gun systems having the feasibility of retro fitment on existing and under construction warships. An apt example is the selection of the MK 46 GWS for US Navy’s LCS and LPD 17 programs. The MK 46 GWS is capable of defeating small, fast, highly maneuverable surface craft.
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Indian Naval ships have the following main guns; A-190(E) 100mm, AK-100 100mm naval gun,AK-176-M 76mm gun,AK-76/62 76mm gun, Twin mount gun (76mm), OTO Melara SRGM 76 mm gun. The CIWS guns include; AK-630 six-barreled 30 mm Gatling gun, and the AK-230 twin 30 mm gun. Indian Navy had placed an RFP for 127 mm guns in Nov 2013, reports in the media indicate that Oto Melara has been shortlisted by the Ministry of Defense to supply thirteen 127mm guns to the Indian Navy. Two of the guns would be supplied directly and 11 would be license produced by BHEL Haridwar. Oto Melara emerged as a single bidder since BAE Systems UK had failed to respond. As far as smaller caliber guns are concerned, a RFI for 30 in number 40mm guns with EOFS has been issued in 2011 and the DAC has in addition cleared a proposal for 116 in number 30 mm guns for the warships. Indian Navy has also raised an RFI for 12.7 mm heavy machine guns for ships and rigid inflatable boats (RHIB).
Some of the popular and interesting guns and gun systems are briefly described in the succeeding paragraphs.
Heavy Guns. The Oto Melara 127/64 LW – VULCANO System consists of four key sub-systems, namely, the medium caliber 127/64 LW Gun assembly, the Automated Ammunition Handling System, the Naval Fire Control Support and the VULCANO family of ammunition. It is intended for surface fire and naval gunfire support as main role and anti-aircraft fire as secondary role. The compactness of the gun feeding system makes possible the installation on even narrow section ships. It is designed with a modular feeding magazine, having four drums with 14 ready to fire rounds each. The drums can be reloaded during firing and there is flexibility in selection of type of ammunition. The ammunition flow is reversible as rounds can be downloaded automatically. The gun can fire standard 127mm / 5 inches ammunition as well as the new VULCANO family of ammunition. The VULCANO allows a smooth integration with any Combat Management System since it has digital / analogical interface and ballistic calculation capabilities.
The Automatic Ammunition Handling System is a modular solution, which can be adapted to any ship’s ammunition magazine layout; the loading of the feeding magazine of the gun does not require gunners during operation and thus permits sustained firing of the gun. The Naval Fire Control Support is a mission planning system that can also support the Combat Management System for definition of possible firing solutions, ammunition selection, trajectory definition, and best ship course identification. VULCANO ammunition family, comprises of Ballistic Extended Range (BER) and Guided Long Range (GLR) ammunition with different multifunctional fuses, sensor and final guidance. This provides extended the ranges of the gun up to 100km. It is also noteworthy that the 127/64 LW VULCANO System is free of the International Traffic in Arms Regulations (ITAR).
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The OTO MELARA 76/62 SR, in service with 58 Navies worldwide as also with Indian Navy, is a multirole medium caliber naval gun mount, designed for anti-missile and anti-aircraft roles. The 76/62 gun can fire at the rate of 120 rds/min, thereby delivering a large amount of ammunition payload on the target.
The advancements in ammunition for this gun would be of significant interest to the Indian Navy as the 3AP fuse increases the lethality of this gun significantly in asymmetric and air threats. It is effective in meeting requirements of both, high speed maneuvering missiles and the new NSFS and ASuW, emerging from Littoral warfare. The 3AP fuse can fit the 76/62 pre-fragmented ammunition, ensuring reliable performances in critical engagement conditions, such as those involving sea skimming missiles and fast maneuvering boats. The 3AP fuse is programmable in three modes; Impact (Fast and Delayed Action); Time (Volume Saturation and Air Burst); and the Proximity (Standard, Gated, Anti-Missile, Conventional Air Defense, Air Defense, Anti Surface). The 3AP fuse has a microwave RF sensor, which behaves like a seeker detecting the target at long range. The relative velocity and position are measured and a built-in CPU sets up the trigger point of maximum lethality. In addition, a Digital Signal Processor provides full rejection of sea clutter at minimal distance from sea surface. What is of importance is the fact that the 76/62 gun mount including the ones already in service can be upgraded by the introduction of a Fuse Programmer Device.
DART (Driven Ammunition with Reduced Time of flight) guided projectile, has also been developed by Oto Melara, it can be re-vectored towards the target during its flight. It can be fired by 76mm Strales system. The STRALES is highly effective against anti-ship missiles. DART is a sub-caliber projectile with canard which is directed to the target by the guidance beam generated by an antenna placed on the gun mount. Its effectiveness is further increased by 3AP microwave programmable fuse .and pre-fragmented warhead.
As far as coastal gun batteries are concerned the Indian Navy can look at heavier gun systems like the 155mm (6-inch) Advanced Gun System Light, manufactured by BAE Systems (Minneapolis) , which provides a heavy volume, precise and sustained gun fire support. The Long Range Land Attack Projectile, LRLAP ammunition is being developed by BAE Louisville, Kentucky and Lockheed Martin Missile and Fire Control, Orlando, Florida. The LRLAP for AGS-L is capable of hitting targets at a range of 74 nm at the rate of six rounds per minute with the rocket booster assisted launch. It is multi piece ammunition and the shell is loaded with modular launch charges and rocket booster. AGS-L can also fire a high capacity ballistic 155 mm ASuW projectile (ASuWP). The AGS-L can store up to 240 LRLAP and 48 ASuWP.
Guns below 40 mm caliber. BAE Systems is working on the Mk 38 Mod 3, in partnership with Rafael, Israel. The Mod 3 uses a 30 mm ATK cannon with a coaxial .50-caliber M2 heavy machine gun in place of the 25mm M242 cannon that is fitted on the Mod 1 & 2 mounts. The 30mm cannon provide a 500-meter longer effective range over the M242 Bushmaster. The Mod 3 has a greater range of elevation: -20 degrees to +75 degrees to engage air targets such as unmanned aerial vehicles (UAV) and helicopters. The Mod 3 mount carries about three times the ammunition load of the existing gun mounts.
The MK 46 GWS is a remotely operated naval gun system that uses 30mm high velocity cannon, a forward looking infrared sensor, a low light television camera, and a laser rangefinder for shipboard self defense against small, high speed surface targets. The gun can be operated locally at the gun turret or remotely at the Remote Operating Console in the Combat Information Centre (LPD 17 class)/Mission Control Centre (LCS class). It has a range of 2000 meters and a rate of fire of 200 rpm. The system includes the MK 44 Mod 2 30mm Bushmaster II cannon, i.e. a single barrel, open bolt, dual feed, electrically powered, chain driven automatic cannon.
Oto Melara claims that its twin Fast Forty 40 mm gun, firing 900 rounds per minute, can kill an incoming supersonic missile at ranges up to 3,280 yards (3,000 m). The mount automatically switches from the lighter HE round to the heavier APFSDS when the missile reaches a range of 1,100 yards (1,000 m).
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The Bofors 40 Mk4 naval gun system has been designed to be an agile, flexible weapon system that enables a very quick response. Its long range and a high rate of fire are complemented by its low weight and compact dimensions. It has the capability to switch between optimized ammunition types, including programmable 40mm 3P all-target ammunition.
The Nexter Narwhal (Naval Remote Weapon Highly Accurate Lightweight) naval remote weapon system is particularly designed for use in light ships with very high maneuverability for monitoring and close-in combat actions but may also be suitable for heavier tonnage ships. The fully stabilised NARWHAL rapid-fire gun system comes in two variants: NARWHAL 20A with a 20mm M621 cannon and NARWHAL 20B with a 20mm M693 cannon. In its basic configuration, the NARWHAL consists of a gyro stabilised mounting armed with a 20 mm cannon, a day camera, and a fire-control system. It is remotely-controlled from a control panel enabling system operation, target acquisition and tracking and fire opening by the operator.

Fire Control Systems. BEL has developed ”Gun Fire Control System” (GFCS) for the Indian Navy for the P-28 class of ships. The GFCS is a quick reaction, multi-sensor, and multi-weapon, short/medium/long range defense system against air, surface, or shore targets on board naval ships. The GFCS is designed to provide air or surface defense with 76mm and 30mm guns. It will track hostile targets through radars or video tracking systems, based on data provided by early warning search radars. Data generated by sensors is processed and used to control the weapons by directing them in the direction of incoming missiles. It comprises five functional sub-systems: tracker, weapon control, sight control, combat management system, and support systems, each of which can be used as an independent system.
Sagem is modernizing fire control systems for French Naval surveillance frigates. It is using new-generation Electro-Optical Multifunction System (EOMS-NG) to provide fire control for the ship’s 100mm gun as well as contribute to their tactical situation awareness and self-defense. The single unit high-performance EOMS-NG optronic system features day-night infrared search and track (IRST) type passive panoramic observation, identification, tracking and fire control as well as very short reaction time between detection and engagement. Ideal for fighting piracy and illicit traffic, the EOMS-NG will replace the existing Najir optronic system. SAGEM’s VIGY MM is a high precision electro optic fire control system which can be Integrated in a Combat Management System or operated in a stand-alone mode. VIGY MM allows manual or automatic sector surveillance, automatic target tracking, aid to identification and transmission or reception of 3D target designation information. VIGY MM is able to control several guns of different calibers simultaneously. It is easy to operate and maintain. VIGY MM comprises of, a high-performance gyro stabilized platform providing an accurate line of sight, a ballistic computer allowing high accuracy gun firing, and a Man-Machine Interface (MMI). VIGY MM has high reliability, performance, and accuracy. Over 400 systems in the VIGY MM range (formerly PANDA, LYNX, NAJIR Mk1, Mk2, and 2000, VIGY 20) are currently operated by 30 navies worldwide.
Conclusion. Promising development of the laser weapon system ‘LaWS’, whose prototype has undergone successful trials on board USS Ponce in the recent past may lead to a very cost effective solution against small boats and UAVs, but it cannot replace the naval gun in all its roles. The electromagnetic rail gun, has potential and can fire non explosives shells to large distances (>100Kms) with great accuracy at velocities up to 7.5 Mach, but it is still some time away. The missiles, despite their falling prices cannot match the cost benefits accrued by the traditional naval gun. On the other hand, rapid technological improvements in gun shells and fuses have satisfactorily demonstrated very high ranges (>100Kms) and accuracies. The naval gun thus continues to be entrenched in its position as the main work horse armament on board ships of the major navies and is likely to remain the mainstay of warships at least until 2025 if not up to 2040.