Improving the capability of a future OPV squadron (Part 2)

This is the second of a two-part article by John Dunbar looking at OPV’s in Royal Navy service. Part 1 considered the way they could be deployed, this article focuses on the ship’s specifications and potential capabilities.

Jack of some trades – master of none

The primary complaint about the Navy’s current and future OPV’s is that they are jack of a few trades, incapable of many roles and master of none. Given the lack of aviation hangar facilities and with minimal weaponry, the River class OPV’s in their current form will often be limited to short range surveillance relying on radar or mark one eye ball to identify targets and the two pacific ribs with boarding parties to intervene. This is very much a barebones capability, and the Batch 2 OPV’s are arguably solid platforms capable of contributing much more to UK defence if their fit out is suitably developed and invested in over time.

Whilst Batch 2 OPV’s are large enough to be equipped with a much enhanced weapons fit (the German Branschweig class corvettes are 1,700 tonnes compared to a Batch 2 OPV at 2000 tonnes) they are not warships and their primary role must remain focused on providing a cost-effective presence where the capabilities of a frigate or submarine are unavailable, unnecessary or better deployed elsewhere. Investment should therefore focus on improving intelligence and surveillance gathering ability – enhancing the patrol rather than warfighting role – whilst taking into account opportunities to act in consort with other Royal Navy assets (and all the time without losing the economy of a lean manned ship!).

Make modular UAV capabilities available

The lack of a hangar capable of supporting indigenous helicopter operations has been the subject of much criticism. However, looking at the Fleet Air Arm inventory, it seems unrealistic to expect the existing numbers of Merlin or Wildcat helicopters to be sufficiently available to support operations from OPV’s on a permanent basis. A helicopter would also require an additional air compliment of around 12 crew to be accommodated, placing further demands on limited RN manpower and driving up OPV operating costs.

Unmanned Aerial Vehicles could be integrated relatively easily, and deployment of Scan Eagle has already proven capable of significantly enhancing the operation of frigates and destroyers. UAV’s typically have lower capital costs, lower operating costs, lower manning and training demands, and offer levels of availability and mission duration many times that of a helicopter. Taking resources and finances into account, UAV’s probably the right choice for RN OPV’s. The step-change in OPV utility would be impressive. Assuming a 15km radar horizon, a batch 2 OPV has the capability to directly monitor around 700 km2 of ocean surface. In comparison;

  • Scan Eagle can operate at a range of up to 100km with mission durations of up to 20 hours. In November 2015 the Royal Australian Navy tested a Scan Eagle fitted with an advanced video reconnaissance system which enabled detailed video surveillance of an area of 45,000 km2 over a 12 hour period.
  • The Scheibel Camcopter 100 has an operating range of up to 180km from its control station and is capable of mission durations up to 6 hours. This could effectively extend an OPV’s ‘reach’ to an area in excess of 100,000 km2,

Given that even in a best-case scenario, four OPV’s might be available for deployment in home waters, it is clear that integrating UAV capabilities would radically improve protection of the UK’s 770,000 km2 EEZ, and make OPV’s genuinely valuable in counter narcotics, terrorism, piracy and people smuggling operations as well as providing improved situational awareness when delivering humanitarian aid.

Improve SIGINT and ELINT capability

Having invested in the OPV platform and its running costs, the ability to gather signals and electronic intelligence should be maximised. Combined with evolving UAV eavesdropping technology, OPV’s could provide persistent, low-cost electronic surveillance capability, particularly in littoral environments e.g. off the coast of Libya or Somalia. In the age of big data, capturing large packets of electronic information for analysis opens up new possibilities – and it is worth noting that the RAF has been particularly successful in sustaining its reconnaissance capabilities in the face of cuts on the basis of intelligence gathering performance in recent and ongoing operations.

Add anti-submarine surveillance capability

OPV’s are not a substitute for the anti-submarine warfare capabilities of a frigate or submarine – and it would be wrong to pretend that they are – but given the difficulty in detecting modern submarines, it is worth considering how OPV’s might contribute to a more effective detection capability, particularly in UK waters where protecting the at sea nuclear deterrent is a priority.

Sonar technology continues to improve, and systems such as Thales CAPTAS-1 towed array sonar are capable of detection at long-range and are designed to operate from noisy medium-sized platforms and as a containerised fit out. Alternatively, the ability to act as mother ships to future unmanned sub-hunting technology would be valuable additional capability and should be explored. There is a need for improved passive underwater surveillance of UK waters. The RN lacks small conventional submarines ideal for the task but additional towed array platforms available to work in conjunction with frigates and future Maritime Patrol Aircraft would be a big help.

Fitting a simple hull mounted sonar – such as Thales Bluewatcher which is based on the same technology utilised by the Merlin FLASH dipping sonar – would enable them to work more effectively in collaboration with and as a platform for Merlin ASW helicopters to interrogate any potential threats identified in UK waters would be another an even cheaper solution.

  • batch2upgrade-medium
  • Sister ship the Brazillian Navy's OPV Apa - note the 20mm cannon on the bridge wing

    Sister ship to the RN’s River class, ‘Apa’ of the Brazilian Navy – note the 20mm cannon on the bridge wing

Improve self-defence capability

OPV’s on overseas deployment – particularly in the Mediterranean and East of Suez – can still expect to face a range of low to mid-level threats, particularly if they are undertaking intelligence gathering activities. These threats might include small boat swarm attacks, torpedo and gun boats, land based or surface based anti-shipping missiles and – less likely but still possible – attack by aircraft.

Assuming that Batch 1 OPV’s are retained for UK home waters operations only, improved self-defence capability would need to be focused on batch 2 OPV’s. As set out at the start of this article, this should be predicated on being able to safely undertake intelligence gathering and constabulary missions rather than integrating a warfighting function – if an attack is considered likely, then an OPV is probably not the right vessel to deploy in the first case. The aim should be to protect against an unanticipated direct threat and withdraw.

Batch 2 OPVs are fitted with CMS-1, the common command system intended to be fitted to all Royal Navy warships meaning that the command and control software for the entire range of Royal Navy weapons and technology is already available.

Provision of basic soft kill anti-missile protection consisting of Sea Gnat would be a sensible step for all Batch 2 OPV’s (plenty of which should be available from recently decommissioned Type 22 and 42 frigates). If a hull mounted sonar is fitted this should be capable of passive torpedo detection and could be linked to soft kill launchers for torpedo defence.

Whilst substituting the 30mm DSB main armament for a medium calibre gun such as the Oto Malera 76mm or Bofors 57mm may seem an attractive option, neither are currently in RN service; both would require extensive re-design and re-building to integrate into complete hulls; both would increase crew numbers needed for operation; and both are largely unproven in dealing with the missile threat.

As an alternative, adding 25mm cannon either side of the bridge (as per Amazonas corvettes) and substituting a Phalanx CIWS for the rear crane would provide an effective and much enhanced self-protection capability across the full range of likely threats without the need to structurally alter the existing Batch 2 design.

Whilst phalanx is expensive, it is unlikely that more than 1 or 2 would be required for OPV deployments at any one time, and integration risks are low given its current RN use in service. These could easily be transferred to any additional future Type 31 frigates (which may take on similar tasking as they come into service) and as such should represent a ‘no regrets’ investment given the improved crew protection they would provide.

Interim OPV squadron

Retaining the Batch 1 OPVs and small, affordable upgrades to the Batch 2s would provide the RN with a significant interim capability, at least until the arrival of the new frigates. This is not playing at fantasy fleets but utilises ships the RN already has and is building right now. This is an outline proposal only that could be reshaped, depending on operational requirements. In principle it could allow for a 4-ship home waters and fishery protection squadron as well as permanent forward-basing of vessels in Gibraltar, Bahrain, The Caribbean and Falklands, relieving pressure on the escort fleet.


Part 1 of this article argued the case for retaining Batch 1 OPVs in service. There is a great deal of potential to improve OPV fit out to meet likely demands of the wide range of roles they may be asked to undertake. Integrating UAV’s is a ‘must have’ priority to justify the circa £600m cost of building the new OPV’s given the lack of indigenous helicopter capability. Considering how to maximise other potential surveillance capabilities will be important in justifying what are arguably modest increases in capital investments and running costs associated with an enhanced fleet of nine OPV’s .

Whether by accident or design, the basic specification of the Batch 2 River Class goes a long way to preclude any hint of war fighting role but fears will undoubtedly persist that improving the capability of OPV’s will undermine funding for future surface combatant numbers. This should not, however, prevent the case being made for maximising the capability of River Class OPVs so that they can make a genuinely positive contribution to UK and overseas security, a motley crew of shapes and sizes though they may be. In the absence of that investment, real questions will remain as to decisions which have led to their construction in the first instance.

Estimated capital costs of upgrading the Batch 2s (excluding support): 6 x rotary UAV Systems 30m; 9 x Modular Towed sonar Array £27m; 10 x 25mm Cannon (2 each for 5 x Batch 2 OPV) £8m; 3 x Phallanx CIWS £25m. Misc Integration/modification costs £10m  Total £110m.

**Batch 1 running costs are estimated at £16-20m per annum.