Surface Weapons for the Littorals

The Indian Navy is set to acquire over 80 new warships, including two aircraft carriers and nuclear submarines each, scheduled to join its fleet in the coming decade, with about five major combatants being commissioned every year

“A good gun causes victory, armour only postpones defeat.” — Vice Admiral S.O. Makarov

Issue: 6 / 2012By Rear Admiral (Retd) Dr S. Kulshrestha

Littoral warfare has come as a reality check for the blue-water forces as they have to also take the littorals in their fold for operations. This involves their capability in countering the threats in very shallow waters of diesel submarines, mines and swarm of hostile boats in adversary’s home waters. In addition, they have offset threat from the near shore defences of missile batteries, gun batteries and air attacks before they can gain entry to the coastal areas. The navies during the cold war period have been outfitted for a standoff combat on the oceans as against a battle in the littorals, the focus has to shift to tackling challenges emanating from the virtual shores, as ships have to perforce operate in littorals for gaining unfettered access to areas of national interests. The international waters commence from 12 nm (about 22 km) onwards and allow unrestricted freedom of movement for boats and ships, which in turn implies that smaller craft can come sufficiently close to warships with the intention of causing harm, before the warships can ask them to stand clear. The traffic in littorals is fairly heavy, with small craft poorly equipped for effective communications, fishing in groups, deficient markings and disparities in language. It is therefore convenient for hostile craft to mingle with local craft, hide their weapons until the last moment and carry out attacks in swarms. Further these craft have excellent knowledge of local waters, weather and topography due to which they can carry out their operations with ease. The identification of hostile craft and neutralising the threat within the short reaction time presented by them, presents a formidable problem.

Till recently, blue-water navies were used to operating with long-range stand-off weapons in the open seas and ships were built to meet the surface threats emanating far away from shores. The carrier battle groups, missile cruisers and destroyers could direct formidable firepower against shore targets, by utilising their air power and missiles at long ranges. Thus also enabling projection of power from stand-off distances in the littorals and carry out support of land operations. The blue-water operations required large ships with great firepower. However, the littorals need agile ships with weapons which can rapidly attack multitude of targets for survivability. Since naval ships are built to operate over decades, there existed a large gap with respect to warfighting equipment in the littorals.

Naval Guns

Traditionally, naval ships have been equipped with a heavy gun (57mm calibre upwards), an auxiliary gun of up to 35mm calibre and a small calibre gun for close air/missile defence, the number of turrets depending upon the size and role of the specific ship. These guns are not effective at very close ranges against surface craft due to inability of the guns to rapidly train, elevate or depress to prosecute swarming targets from different directions at close quarters. Examples of some heavy guns include Oto Melara 76mm gun, (traditional/compatto/rapid), Bofors 57/70mm MKII/MKIII, CADAM Turret/Loire 100mm/MK55 Mod 68, Oto Breda 127/54, Oto Melara 127/64, and Giat CADAM Turret. The auxiliary guns include, Oto Breda 40/L70 twin, Mauser EADS MLG 30/27mm, Rheinmetall GDM-08 with MSP 500, Oerlikon Gam/BO 1, Allied Telesyn DS 30M automated small calibre gun system, Rheinmetall RH 202. The close in weapon systems includes, Mauser Oerlikon MeRoKa, Signaal GAU-8/A, GE/GDC MK 15 Mod 2, Raytheon/Diehl RIM 116 Block 1 HAS.

Incidentally, the US Navy’s requirements for the LPD 17 and LCS ship programmes included the need for weapon systems capable of defeating small, fast, highly manoeuvrable surface craft. The MK 46 gun weapon system (GWS) was selected to provide these ships a capability against small surface craft. 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 defence 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).

The small hostile craft’s weapons of choice include handheld weapons (the PK/RPK 7.62mm, the NSV 12.7mm, the Rheinmetall MG 3, the AK 47, AK 74, the FN FAL, the H&K G3, etc), and rocket launchers like RPG-7. Scenario and simulation studies have established that most of the North Atlantic Treaty Organisation (NATO) frigates are vulnerable to an attacking swarm of four to eight such small hostile craft. Various studies have also revealed that ships using a mix of sophisticated high and low calibre weapons with high probability of hits, have much greater chance of survivability then those with semiautomatic systems. This has led navies to resort to upgrading or modernising the main and auxiliary gun and close in weapon system (CIWS) outfits. The upgrades include both sophisticated software and the ordnance. The aim is to achieve a high firing rate coupled with very high hit probabilities. Feasibility studies have confirmed possibility of retrofitting of modern systems on existing platforms.

Current Popular Gun Systems

The Italian Oto Melara 127/64 LW lightweight naval gun is used on board the Italian frégate multi-mission (FREMM) and the German F125 frigates. This rapid fire gun can be installed on large and medium size ships, for surface fire and naval gunfire support, with anti-aircraft fire as its secondary role. The compactness of the gun feeding system makes it possible to install it on narrow section craft. The gun can fire all standard 127mm/5 inches ammunition including the new Vulcano long-range guided ammunition. Vulcano is a family of extended-range (ER) unguided ammunition and long-range (LR) guided ammunition for the 127mm naval guns and 155mm land artillery system. Vulcano is a new and emerging technology based upon a fin stabilised airframe with canard control for terminal guidance; mechanical interfaces are same as standard 127mm ammunition. Various configurations for Vulcano projectiles are available for 127mm naval gun as unguided extended-range multi-role ammunition, guided long-range ammunition with infrared (IR) seeker and autonomous inertial measurement unit (IMU)/global positioning system (GPS)-guided ammunition.

The Oto Melara 76/62 super rapid (SR) gun, today in service with 58 navies worldwide, is a multi-role medium-calibre naval gun mount, designed for anti-missile and anti-aircraft as main role, and conceived for installation on multi-purpose ships of any class and type. From the operational point of view, the 76/62 gun can fire at the maximum rate of fire 120 rds/min, without interruption, delivering a huge amount of firepower in a very short time and at long ranges. The 76/62 gun’s powerful and stabilised servo systems allow fast reaction to rephasing commands from one target to the other and precision and accuracy in aiming. Moreover, the mount can also be fitted with a dual or multiple ammunition feeding system in order to provide the user the capability to easily and rapidly select from the carousel different types of ammunition in accordance with the incoming threats.

The 76/62 gun mount can be deployed for Naval Gunfire Support (NGS), antisurface warfare (ASuW), anti-air warfare (AAW), anti-missile warfare (AMW) and asymmetric warfare in particular. The latest developments in the ammunition field have placed the 76/62 gun mount in an enviable position in terms of lethality in countering asymmetric threats and air targets, including both high speed manoeuvring missiles and the new NGS and ASuW requirements, emerging from littoral warfare.

The 3AP fuse can fit the 76/62 pre-fragmented ammunition, ensuring top performances in critical engagement conditions, such as those involving sea-skimming missiles and fast manoeuvring boats. The 3AP fuse can be programmed in three operating modes: Impact (fast and delayed action); Time (volume saturation and air burst); Proximity (standard, gated, anti-missile, conventional air defence, air defence, ASu); 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. Moreover, a digital signal processor provides full rejection of sea clutter at minimal distance from sea surface. All the 76/62 gun mounts, including the ones already in service, can be upgraded by the introduction of a fuse programmer device.

DCNS has awarded a contract to Sagem to modernise the fire control systems onboard the French Navy’s six Floreal class surveillance frigates. Under the contract, Sagem will modernise fire control systems based on new-generation electro-optical multifunction system (EOMS-NG) to provide fire control for the ship’s main artillery, a 100mm gun as well as contribute to their tactical situational awareness and selfdefence of the ship. The single unit highperformance 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, 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 simultaneously control several guns of different calibres. It is easy to operate and maintain. Vigy MM comprises:

  • A high-performance gyro-stabilised platform providing an accurate line of sight
  • A ballistic computer allowing high accuracy gun firing
  • A man-machine interface (MMI)

Drawing on Sagem’s 30-year experience in electro-optical detection and fire control, Vigy MM capitalises on its predecessors’ proven 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.

Nexter ARX 20 cupolas comes as an alternate solution, compared to the 12.7mm systems and the turrets fitted with a 25 or 30mm gun with its compactness and low weight similar to 12.7 machine guns, 20mm guns fire more powerful projectiles. The Nexter naval remote weapon, highly accurate, lightweight (NARHWHAL) naval remote weapon systems is particularly designed for use in light ships with very high manoeuvrability for monitoring and close-in combat actions but may also be suitable for heavier tonnage ships. The effectiveness of the weapon is optimised by a stabilised sight associated with a fire-control system, while improving the operator’s safety. In its basic configuration, the NARHWAL consists of a gyrostabilised mounting armed with a 20mm cannon, a day camera and a fire-control system which is remotely-controlled from a control panel enabling system operation, target acquisition and tracking, and fire opening by the operator.