Harpoon Surface to Surface Missile
The RGM-84 Harpoon is a ship-launched, all-weather, over-the-horizon, anti-ship missile. It is due to be replaced with the Interim Surface to Surface Guided Weapon System (I-SSGW) and Future Cruise and Anti-Ship Weapon (FCASW) in due course
The Harpoon surface to surface missile was described by the Royal Navy as;
Harpoon is the long range lance of the Type 23 Frigate, capable of destroying enemy ships far beyond the horizon. Fitted to all Type 23 Frigates the Harpoon is a sophisticated anti-ship missile capable of striking targets more than 80 miles away. Harpoon uses a combination of inertial guidance and active radar homing to attack it’s prey. Cruising at Mach 0.9 and carrying a large high explosive warhead it is powered by a lightweight turbojet, but is accelerated at launch by a booster rocket.
It is currently fitted to the Type 23 Frigate and Type 45 Destroyer.
Harpoon is unlikely to be transferred to the Type 26 or Type 31 Frigates
Development of the Harpoon missile for the US Navy goes back to the mid-sixties as a counter to surfaced submarines but for the Royal Navy, it first came into service as a submarine-launched weapon in the mid-seventies.
The Royal Navy had a requirement for an Under Surface Guided Weapon (UGSW). Choices were a new development from Hawker Siddeley, designated CR137, the McDonnell Douglas Astronautics Harpoon and an Anglo-French development called Sub Martel. Sub Martel was a modification of the already in service Matra Martel air to ground missile but compared to the already in service Harpoon, would require significant development funding.
Although Exocet was in service with both the UK and France, a submarine-launched development project was not considered for UGSW.
In September 1975, the MoD selected the Harpoon missile, the French went on to develop SM39 Exocet, the submarine-launched variant. A $6m pre-development contract was awarded to McDonnell Douglas to investigate modifications to enable use by Royal Navy submarines. Part of the deal was that British companies would design and develop the torpedo tube launch capsule
Whilst this was ongoing, Norway, the UK, USA, Germany and the Netherlands had embarked upon the Anti-Ship Supersonic Missile study that would eventually go nowhere.
For the next year or so there was a great deal of negotiation on UK subcontract components and other industrial issues. By 1981, the Royal Navy had commenced firing trials of UGM-84B Sub Harpoon from Trafalgar and Swiftsure attack submarines. Sub Harpoon was first deployed on HMS Courageous at the end of the Falklands Conflict in 1982. Also a short time after the conflict, some RAF Nimrod MR.2 aircraft were fitted with air-launched Harpoon missiles. A small number were subsequently purchased.
In 1983, McDonnell Douglas offered the 120nm range RGM-84 Harpoon Block 1C for use on the Royal Navy’s Type 22 and Type 23 frigates. Block 1C offered various improvements including increased range (80nm), waypoint navigation and lower altitude flight. The surface-launched storage and launching canister was originally developed for hydrofoil deployment.
In competition with Harpoon was a surface-launched variant of Sea Eagle, the P5T. Sea Eagle was by then entering service with the RAF and Fleet Air Arm. The launch canister for Sea Eagle SL was adapted from a lightweight Sea Dart canister.
Whichever missile won, it was intended to equip the first Type 22 Batch III Frigates. Exocet was not considered suitable and neither was Otomat.
In 1984, Harpoon Block 1C won and a contract for £200 million was placed with McDonnell Douglas, to be designated GWS.60.
Sub Harpoon was withdrawn from Royal Navy service in 2003 with no direct replacement but a surface-launched Harpoon Sustainment Programme was initiated to maintain Harpoon to its OSD.
At the UK/French 2016 Summit an intent to co-develop a joint concept phase for the Future Cruise/Anti-Ship Weapon (FC/ASW) programme was announced. Storm Shadow was subject to a Mid-Life Refurbishment (MLR) that will meet the SPEAR Capability 4 requirement, and take it to its planned out of service period of around 2030, when it will be replaced with the SPEAR Capability 5 system, nominally, the UK/France Future Cruise and Anti-Ship Weapon (FCASW) / Futur Missile Antinavire/Futur Missile de Croisière (FMAN/FMC).
The MoD provided greater detail the following year;
The Type 26 Frigate will be delivered with cutting edge weapons and sensors that build on the excellent operational record of the Type 23. Investment in the MK 41 launcher enables the Royal Navy the option of investing in a wide range of additional capabilities at short notice and according to the threat. The Type 26 Global Combat Ship will be fitted with the Mk41 Vertical Launch Silo, providing options for development of Type 26 capability throughout its life. Type 26 is planned to be a key component of the RN’s fleet until at least 2060 and it makes sense to build a strike missile launcher into its design that enables a flexible choice of weapons throughout its service life.
The Mk41 Vertical Launch silo provides the flexibility to field a variety of weapons, which may include the next generation of ship-launched strike weapons – including the Future Offensive Surface Weapon and the Next Generation Land Attack Weapon – being developed through the MOD’s current ten-year, £178 billion equipment plan.
The current planning assumption is that Future Cruise /Anti-Ship Weapon will enter service on the T26 Frigate and Typhoon aircraft in 2028 and 2030 respectively
Harpoon equipped Type 22 and now equips Type 23 Frigates. A small number of Type 45 Destroyers have also received the launching system from withdrawn Type 22 Frigates. The current Out of Service Date (OSD) for Harpoon was planned to be 2018, the In-Service Support contract with Devonport Royal Dockyard Ltd ran to November 2018. Like all planned OSD’s though, this changed with a slight extension to 2023 to retain it in service until the Interim Surface to Surface Guided Weapon System (I-SSGW) enter service.
The Royal Navy continuously reviews the capabilities it requires. While work is in hand to consider options for the replacement of the Harpoon missile system, the Navy has decided to extend its service life beyond 2018.
On the 28th of August 2019, the MoD issued a tender note for the Interim Surface to Surface Guided Weapon System (I-SSGW)
The TTH project team, part of the UK Ministry of Defence, hereafter referred to as the authority, has a requirement for the provision and introduction into service of the I-SSGW system as an interim replacement for the existing system that is going out of service. The I-SSGW is to provide a ship launched over the horizon precision anti-ship capability and a terrain following precision maritime land attack capability. It is anticipated that the I-SSGW capability will operate on X 5 Type 23 (Towed Array) frigates capable of concurrent Anti-submarine warfare (ASW) and Anti Surface Warfare (ASuW) operations in protection of a formed Maritime Tasking Group, for a 10-year period.
Longer-term, Harpoon and I-SSGW are planned to be replaced by Future Cruise and Anti-Ship Weapon (FCASW).
The terrain-following requirement likely excludes Harpoon and Exocet. It was speculated that bidders might include the Lockheed Martin Long Range Anti-Ship Missile (LRASM), Kongsberg Naval Strike Missile (NSM), Saab’s RBS15 Mk4 and the Gabriel V from Thales/IAI called the Sea Serpent.
A March 2021 Written Answer provided an update
The interim surface-to-surface guided weapon will replace the Royal Navy’s existing Harpoon missile capability. There was a healthy response from Industry to the Pre-Qualification Questionnaire and we are planning to proceed to issue an Invitation to negotiate to the down selected bidders later this year.
After being launched through a torpedo tube the sub harpoon capsule is activated by the snapping of a safety lanyard. Fins deploy to ensure the capsule assumes a vertical position and it then rises to the surface when the nose and tail caps blow off. The rocket booster ignites and the missile is propelled to a suitable altitude when the main propulsion motor fires.
For the surface-launched variant, currently, in service, the missile is fired from an angled tube launcher with frangible front and base caps. The tubes are arranged in groups of four, with two groups arranged to fire port and starboard.
The missile is 4.6m long and weighs 691kg (with booster). The warhead weighs 221kg, approximately the same as a Paveway IV or half the weight of the Storm Shadow warhead. The maximum speed is 885kph.
Guidance for Harpoon is performed initially by information provided by the launch platform, waypoints and mid-course changes can also be programmed into the inertial guidance system. Terminal guidance is carried out using the integral radar seeker. The attack profile is also selectable at launch.
Because of the lack of a data link and the radar terminal guidance feature, Royal Navy Harpoons are often considered to be obsolete in a contemporary operating environment. Future developments, not currently in service with the Royal Navy, are planned to incorporate improved target discrimination and data links to enable its deployment in complex environments with civilian and military vessels in the same area.
Type 23 Harpoon Launch
Type 23 Harpoon Launch Video
Harpoon General Characteristics
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