Naval RWS, more than just UAS swatters

There is a growing need to add remote weapons stations onto naval vessels to counter a range of emerging threats such as unmanned and swarming.

Remote weapon stations (RWS) for naval vessels offer a significant improvement in combat capabilities compared to manned weapons. One major advantage is that crew members can operate the weapon from inside the ship protected from both the weather conditions and enemy fire. Fitted with surveillance and targeting systems and available in a range of different medium calibre weapons, the RWS is cost-effective for ship self-defence at close quarters, particularly out to 160 feet (50 metres) and beyond, as well as for maritime interdiction operations where a large main gun or missile system is not the wrong choice due to size and expense.

In the crowded littoral environment at maritime choke points or along busy shipping lanes, there are a plethora of different commercial craft around that can make the detection of an asymmetric threat much more difficult. Under these conditions the more powerful long-range weapons of large frontline warships which are designed for oceanic warfare are negated. Therefore, ships must rely on the smaller weapon systems with specialised sensors for effective engagement in these surroundings.

The utility of RWS allows them to be fitted to a wider range of ships from small boats, patrol ships and fast attack craft up to frigates, amphibious ships and logistics vessels. There are also a growing number of unmanned surface vessels being developed that are capable of using RWS. Recent procurement activity and RWS developments highlight the growing popularity of these systems.

Israeli company Rafael announced on 7 December 2022 it had been awarded a contract for its Typhoon Mk30-C variant RWS by an undeclared Asian navy customer. The company stated that this variant is fitted with the Northrop Grumman Mk44S Bushmaster 30mm gun which, firing at a rate up to 200 rounds per minute (rpm) with 70° elevation and air- bust munitions, is better able to conduct counter-UAS (C-UAS) missions to defeat multiple small and medium size targets.

The ability to conduct C-UAS tasks is indicative of trends in the development of RWS. The growing threat of drones against surface ships means that RWS are starting to include a more sophisticated air defence capability alongside the standard anti-surface capability against small fast boats. As well as upsizing there is the challenge of downsizing so that very small boats can be fitted with heavier weapons. Rafael’s lightweight Mini-Typhoon RWS is usually fitted with the M2 Browning .50cal (12.7mm) machine gun. It weighs about 308-375 pounds (140-170 kilogrammes) and can fire 450-575rpm to a maximum range of 5,900ft (1,800m).

A larger 25mm calibre variant of Typhoon RWS commonly using the M242 Bushmaster has been selected for the Royal Australian Navy’s (RAN’s) Arafura-class offshore patrol vessels (OPVs) as an interim measure after the Australian Department of Defence first decided to replace the main gun with the Leonardo OTO Marlin 40mm cannon RWS, but then in February 2022 re-started a main gun competition. Variants of Typhoon RWS are popular and used across the RAN fleet as well as by the Indian Navy, Sri Lanka Navy, Royal Canadian Navy, US Navy, Israeli Navy and Republic of Singapore Navy.

A Rafael spokesperson told AMR that the main trend in RWS development is the ability to start the engagement from a much farther distance. “Each engagement is much more efficient, requiring less ammunition for each target, allowing for engagement with many more targets using the same amount of available ammunition. We believe this is the most effective solution for the emerging surface and Aerial swarm threats,” the spokesperson said.

Medium calibre
Medium calibre guns from 20-30mm are becoming more popular because of the additional range and destructive impact they can offer along with options for specialist ammunition.

The French Navy is installing RWS on both its larger combat ships and smaller patrol vessels to provide additional firepower. One of the features of the French Navy’s lead Frégate de Défense et d’Intervention (FDI) frigate is an asymmetric warfare centre located close to the bridge. It is designed to control ship self-defence against swarms of UAS or fast boats and has a team of specialists that can receive information from the ship’s sensors and can control defensive systems, primarily two Narwhal 20mm RWS provided by Nexter. The first ship will be delivered in 2024.

Narhwal is also being fitted to the six new Félix Éboué-class offshore patrol vessels (OPVs) on order for the French Navy that will be delivered from 2023-2025. The OPVs will replace the existing P-400 patrol vessels that operate in France’s overseas territories. New Caledonia (Nouméa), French Polynesia (Papeete), and La Réunion (Pointe-des-Galets) will receive two each. Narwhal is already installed on most of the French Navy’s existing warships.

In March 2022 the Royal Netherlands Navy (RNLN) followed the French example to put RWS on its ships and awarded Anglo-Italian defence company Leonardo a contract to install the Lionfish Top RWS on several ships in its fleet. These include the four Holland-class OPVs, the landing ship dock HNLMS Johan de Witt, joint support ship HNLMS Karel Doorman and the Den Helder-class combat support ship being built by Damen Naval.

Lionfish was launched in 2020 at the Euronaval exhibition and consists of four different variants. The Top variant is fitted with a 12.7mm machine gun showing that this calibre is still useful for close in self-defence for larger ships. Two others variants are fitted with 12.7mm machine guns – the Inner Re-Loading and the Ultralight variants – which unlike ‘Top’ are designed for small naval craft.

Large calibre
To meet the larger calibre market the Lionfish family has a variant fitted with a 20mm cannon that was due to complete qualification and validation in 2022. A spokesperson from Leonardo told AMR that a few environmental tests are missing to complete the qualification/validation of the Lionfish 20 but confirmed the system already has a launch customer. Leonardo also offers the 30mm Marlin RWS that is being fitted to the four Gowind OPVs that French shipbuilder Naval Group is building for the Argentine Navy.

In December 2022, Leonardo announced that it had been selected to provide Lionfish Top for the Federal German Navy’s four new Type 126 frigates that are being built for the Federal German Navy by Dutch shipbuilder Damen Naval.

“Top is able to autonomously calculate the firing solution and engage fast-moving, manoeuvring and extremely close threats, even when installed on high-speed platforms, thanks to a high performance auto tracking system,” states company literature.

These will supplement the MLG27-4.0 RWS that Rheinmetall is providing for the frigates under an earlier order announced on 17 November 2022. Rheinmetall will deliver eight MLG27-4.0 RWS, two for each of the four ships.

There are options for fitting the system to another two F126 frigates. The Mauser BK-27M 27mm gun can be fired in single-shot mode, adjustable bursts or in sustained fire up to 1,700rpm. The first Type 126 frigate will be delivered in 2028. The MLG27 is already used on the German Navy’s Type 125 frigates with older variants fitted to the Type 122 and Type 124 frigates and the K 130 corvettes.

MLG27-4.0 is also called the SeaSnake 27 and is part of Rheinmetall’s wider Seasnake family of RWS. The SeaSnake 30 RWS variant is being fitted to the four new Tamandaré-class MEKO A-100MB multirole frigates being built for the Brazilian Navy and delivered from 2025. Available since 2020, the SeaSnake 30 RWS uses the Rheinmetall KCE30 cannon that fires 30mmx173mm rounds including air burst munition at a rate of up to 1,100rpm and has a multi-target tracker integrated that can enable simultaneous multiple target tracking and automatic target recognition.

Despite this recent success with its RWS selected for large ships, a spokesperson from Rheinmetall told AMR as larger surface vessel combat engagements were greatly reduced nowadays, the company “envisions the world´s growing market for primary armament of smaller vessels like fast patrol boats, speed boats or RHIBS in favour of brown water operations against piracy, drug trafficking or littoral terrorism.”

Smaller ships that are receiving more RWS as a way of increasing the capabilities of those platforms for a variety of specific tasks.

In the Mediterranean in May 2022, the Hellenic Navy took delivery of Agenor, a new 17.6m-long 22t Special Operations Craft (SOC), which is reportedly the only vessel in the Hellenic fleet to operate a RWS. Agenor is fitted with the Shark lightweight 12.7mm RWS from Israeli company General Robotics. SOC are designed for the covert insertion and recovery of Special Forces (SF) troops, but the trend is for the SOC to be able to defend themselves with a larger calibre weapon than the small arms possessed by the SF.

Shark is fitted with the M2HB 12.7mm machine gun and has a base weight of just 187lb (85kg) and height of only 60cm reducing its silhouette. However, the weight will more than double with the addition of a weapon and power unit.

General Robotics stated that when firing, the AI-driven fire control runs a target prediction algorithm to “align the projectile’s path and the target’s expected location” in order to point the weapon in that direction before firing a burst. “This technique has demonstrated a hit accuracy of about 70 percent,” the company said adding that this can give Shark a C-UAS capability but using a drone jammer instead of a machine gun. A spokesperson for General Robotics told AMR that Shark has recently been ordered by a Middle Eastern customer to equip Commando boats.

A lot of [RWS] systems on the global market have been fitted with 25mm weapons and although still useful is becoming increasingly obsolete,” Jones said. “The 30mm round brings significant benefits, it allows the introduction of new ammunition technology that you can’t fit in a 25mm round including anti-armour, high explosive and a new proximity fuse that is useful against drones,” he added.

“Feedback from the Ukraine conflict is that .50 calibre (12.7mm) equipped systems do not offer sufficient firepower against Russian equivalents using 14.5mm machine guns that outrange the .50cal. There is more interest in lightweight 30mm calibre solutions to defeat that 14.5mm capability,” Jones said.

However, the 12.7mm machine gun capability is still useful for many navies that want a basic inexpensive level of combat capability in their maritime security craft. The Philippines is developing its own naval RWS capability and the Building a Universal Mount for Heavy-Barrel Automated Weapon Integration (BUHAWI) project. The BUHAWI is intended to host the M2 12.7mm machine gun and is likely to be used to equip smaller vessels in the Philippine Navy fleet. The Philippine Navy’s existing six Multi-Purpose Assault Craft Mk 3 are fitted with the Mini-Typhoon out of the current inventory of 12. A total of 42 craft are planned. The vessels have been successful in counter-terror operations against Abu Sayyaf as well as in counter-smuggling operations.

Statements made by Department of Science and Technology (DOST) Secretary Fortunato de la Peña in the Philippines media are that BUHAWI development costs are currently $250,000, which can be reduced to $218,000 when in mass production. This compares with imported systems slated to cost around $436,000. A prototype is ready and testing was due to have been completed in October 2022.

Also in October, Malaysian shipbuilder TH Heavy Engineering (THHE) launched the first of three large 1,800t Tun Fatimah-class Offshore Patrol Vessels (OPVs) for the Malaysian Maritime Enforcement Agency (MMEA). All three OPVs will be fitted with the 30mm SMASH RWS from Turkish defence company Aselsan. The vessels are due to be handed over from 2023 and the MMEA stated that they will be used for patrolling the Luconia Shoals, which are just 54 nautical miles (NM) (100km) from Malaysian Borneo but within its EEZ in the South China Sea. This region is also claimed by China and is therefore an indication of the need for increased firepower for the MMEA to protect Malaysian claims against deliberate Chinese incursion. The larger size of the Tun Fatimah-class allows the MMEA to conduct longer duration missions and host a bigger gun to enforce security in its maritime zone.

At the Indo Defence exhibition in Jakarta, Indonesia in November 2022, it was announced that the Indonesian Army has ordered a new 24m-long 55t Fast Interdiction Craft (FIC) from local shipyard PT Tesco under a contract signed in 2021. The FIC will be used by Army SF units and can be fitted with a RWS hosting a weapon up to 12.7mm calibre. Meanwhile Taiwan’s Republic of China Coast Guard is in the process of taking delivery of 12 700t Anping-class missile patrol boats that are each fitted with two XTR RWS fitted with the T-75S 20 mm cannon.

As the proliferation of RWS on all ship types gathers pace, these craft will become more effective at conducting maritime security operations and improving their self-defence capabilities, particularly against airborne drone swarms. Using the surveillance and targeting systems and higher calibre weapons even smaller vessels will have access to ISR and firepower that is usually reserved for much larger ships. In this way, RWS will contribute towards making all platforms in a fleet more flexible and capable of undertaking a wider variety of roles.