Naval Strike Missiles Have Arrived Aboard Royal Navy Warships

The first look at the British Type 23 frigate HMS Somerset sporting its new Naval Strike Missile anti-ship cruise missile armament has emerged today. Somerset is the first of a total of 11 Royal Navy warships, a mix of Type 23 frigates and Type 45 destroyers, that are set to receive these more modern weapons as a replacement for their aging Harpoon anti-ship cruise missiles. NSM offers a particularly significant boost in capability for the Type 23s, the youngest of which is just over two decades old.

HMS Somerset was seen with its new Naval Strike Missile (NSM) loadout, which the Royal Navy officially calls the Maritime Offensive Strike System (MOSS), as it sailed into its homeport of His Majesty’s Naval Base, Devonport (HMNB Devonport) earlier today. The Type 23 frigate, one of 10 in Royal Navy service today, was returning from a Haakonsvern naval base in Norway, where the missiles were reportedly loaded onto the ship. Westward Shipping News was among the first outlets to capture pictures of the ship with its new weaponry.

HMS Somerset coming into HMNB Devonport earlier today showing off its new Naval Strike Missile armament, which is seen just forward of the main superstructure. Westward Shipping News

Other outlets and local ship spotters published additional pictures and videos of Somerset arriving in Devonport.

HMS Somerset‘s two new four-round NSM launchers are installed in the same general location as the Harpoon launchers had been, directly in front of the main superstructure. Harpoon has been part of the armament on all Type 23 frigates since the first one of these warship was commissioned in 1990.

HMS Somerset in 2011 with its previous Harpoon anti-ship missile launchers visible in front of the main superstructure. Crown Copyright

The Royal Navy released pictures in January showing work to fit the new mounting hardware for the NSM launchers on the ship. Westward Shipping News had spotted Somerset in October with the launchers appearing to be fully installed, but without any missile canisters loaded onto them.

HMS Somerset seen leaving Devonport in October. The NSM launchers are visible, but without any missile canisters loaded on them. Westward Shipping News

NSM is a stealthy anti-ship cruise missile that uses a GPS-assisted inertial navigation system (INS) guidance package to get to the general target area before switching to an imaging infrared seeker in the terminal phase of flight. Its navigation package also means the missile has a secondary land-attack capability against fixed target coordinates. You can read more about NSM and its capabilities here.

By comparison, the 1980s-era RGM-84D Block 1C Harpoon anti-ship cruise missiles currently in Royal Navy service have a non-stealthy design and a significantly shorter stated maximum range than NSM. They also have a much more rudimentary ability to navigate tied to an active radar seeker. Imaging infrared guidance systems are not susceptible to radiofrequency jamming and other types of countermeasures designed to disrupt seekers in that spectrum. The Block 1C Harpoon does have a larger warhead than NSM.

The Royal Navy’s Type 23 frigate HMS Westminster fires a Harpoon anti-ship missile during an exercise in 2023. USN

Somerset otherwise retains the rest of its existing armament, which includes a 4.5-inch naval gun in a turret on the bow, two turreted 30mm automatic cannons for close-in defense, and a pair of twin torpedo tubes. The Royal Navy has also been in the process of replacing the Sea Wolf surface-to-air missiles on all its Type 23 frigates with far more capable Sea Ceptor types. Somerset received Sea Ceptor during an earlier refit last year.

Somerset has been separately in and out of drydock multiple times in the past two years due to serious leaking that emerged after a major overhaul that began in 2018 and was ostensibly finished in February 2022.

Discussions about replacing the Block 1C Harpoons on at least some of the Royal Navy’s Type 23s, as well as the Type 45 destroyers, date back to at least 2019. An Interim Surface-to-Surface Guided Weapon (ISSG-W) program was subsequently initiated, but looked to have been effectively canceled by the end of 2021. The plan then was to refocus resources on the development and fielding of a new, more advanced Future Cruise and Anti-Ship Weapon (FCASW) by the end of the decade.

However, the ISSG-W effort was then rebooted, in large part due to changes in British defense policy stemming from Russia’s all-out invasion of Ukraine in 2022. NSM was officially selected as the Royal Navy’s next anti-ship cruise missile in November of last year, but the specific number of Type 23s and Type 45s that are set to be armed with them remains unclear. Reports also emerged last year that the United Kingdom had transferred some of its stocks of Harpoons to Ukraine to go along with ground-based launch systems provided to that country by Denmark.

Recent events in the Middle East have further underscored the value of refitting Type 23 frigates and Type 45 destroyers with more modern anti-ship missile systems, especially ones with latent land-attack capability. The Royal Navy is now among the naval forces that have been responding to missile and drone attacks from Iranian-backed Houthi militants in Yemen aimed at commercial vessels in and around the Red Sea and the Gulf of Aden, and Bab Al Mandeb Strait that links the two bodies of water together.

There is the potential that an international coalition could retaliate more directly against the Houthis, especially as commercial shipping in the highly strategic region becomes increasingly disrupted. Still, whether or not this happens very much remains to be seen, as The War Zone just recently explained.

The Royal Navy has already been very actively involved in protecting commercial shipping across the Middle East in recent years. In 2019, HMS Montrose, another Type 23 frigate, notably intervened to shield the U.K.-flagged tanker British Heritage from harassment by boats belonging to Iran’s Islamic Revolutionary Guard Corps (IRGC) as it sailed from the Persian Gulf into the Gulf of Oman via the Strait of Hormuz.

All this being said, NSM is still being presented as an “interim” replacement for Harpoon until the FCASW enters service. However, the development of that weapon is currently in its early stages and it remains to be seen what form it will take. Stealthy subsonic and supersonic options are apparently under consideration, and there have been discussions about potential hypersonic designs in the past. There is a general trend worldwide toward the development and fielding of new faster-flying anti-ship missiles.

There is the potential that NSM could remain in service alongside whatever design is ultimately chosen for the FCASW. The NSM’s manufacturer, Norway’s Kongsberg, is currently leading a joint Norwegian-German program to develop a new supersonic maritime strike missile for those countries, which it says will be a complement to its existing design. NSM is still steadily growing in popularity around the world, including in the U.S. military where it is being fielded in ship and ground-launched forms.

A rendering of a new supersonic maritime strike missile that Norway’s Kongsberg is now leading the development of for both the Norwegian and German navies. The company says this weapon will be a complement to its existing subsonic NSM. Kongsberg Defence & Aerospace

The Royal Navy is also looking to retire all of its Type 23 frigates by 2035, replacing them with a mix of new Type 26 and Type 31 types.

However the Royal Navy’s anti-ship missile plans continue to evolve, it now has at least one warship, the Type 23 HMS Somerset, armed with NSM.

Special thanks to Westward Shipping News for sharing the pictures of the NSM-armed HMS Somerset with us.

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Joseph Trevithick Avatar

Joseph Trevithick

Deputy Editor

Joseph has been a member of The War Zone team since early 2017. Prior to that, he was an Associate Editor at War Is Boring, and his byline has appeared in other publications, including Small Arms Review, Small Arms Defense Journal, Reuters, We Are the Mighty, and Task & Purpose.