DefenceSynergia is indebted to David Graham, one of our Founding Members, for his insight into Royal Navy (RN) Mine Countermeasures Vessels (MCMV) and potential for sea mining in the Gulf region. In view of the current situation in and around the Straits of Hormuz David’s analysis is both welcome and prescient. David’s RN and Royal Fleet Auxiliary (RFA) experience and service is extensive. In more recent years he has exercised his professional talent in marine consultancy work in the Falklands, Mediterranean, Africa and Middle East – the latter including Yemen and Gulf region. 

Looking back to the 1950s when Bahrain, Kuwait and what now constitutes the Emirates were British protectorates, it had been United Kingdom policy to station frigates and a small minesweeping force in the Persian Gulf. By the early 60s Ton Class sweepers, based in Bahrain, constituted the 9th Mine Sweeping Squadron [9th MSS], which later became the 9th Mine Countermeasures Squadron. As an example, in 1969/70 this comprised of 11 Ton class, of which 3 were mine hunters. This arrangement continued until circa 1980, and was discontinued in line with the policy of withdrawal from the middle and far east, and with the steady decline in Ton class numbers.

Of interest, a small naval base was built at Aden in the early 60s, and was said to be designed to support mine countermeasures. The author visited it on a number of occasions in 1962/63, but as the British left Aden in the mid-60s, it is unclear whether any RN assets were ever based there. .

After the first Gulf War, RN MCM vessels were based in the region, and in the early years of this century it was decided to forward deploy MCM assets on a permanent basis to the region. These comprised of two Sandown class single role minehunters [SRMH] and two Hunt class Mine Countermeasures Vessels [MCMV] which initially had a mine sweeping capacity. This was removed in 2005, however it is understood that some form of sweep has recently been reinstated. The permanence of the forward deployment arrangement was confirmed in 2013 when the 9th MCM Squadron was stood up at Bahrain.


Hunt class MCMVs

Displacement: 750 tonnes [full load] Dim: 60m x 10-5m x 3-4m Machinery: 2 Caterpillar C32 ACERT diesels: I Deltic 9-55B diesel [plus generation and auxiliary drive], 2 shafts and I bow thruster. Speed 15 kts. Armament: 1 30mm. 2 mini guns. This specification is as modified by BAES and relates to all six ships.

Originally a class of 13 vessels, these were reduced over time to eight, all of which were to be refitted under the BAES contract which embraced new engines, gear boxes, bow thrusters, propellers, hydraulic and control and monitoring systems, designed to meet the unique electromagnetic challenges posed by the role of these, the largest GRP vessels in the navy. Of the eight, two were withdrawn from the project and decommissioned in December 2017. Proposed OSDs plan to have them decommissioned by 2022.They comprise the Second Mine Countermeasures Squadron based at Portsmouth.

NB: Despite these dates, when Middleton completed her refit in 2014 it was officially stated that “the new engines mean that Middleton can sail faster, stay at sea longer, and will extend the ship’s life to 2030 and beyond”. Readers can make of that what they will.

Sandown class SRMH

Displacement: 600 tonnes Dim: 52-5m x 10-9m x 2-3m Machinery: 2 Paxman Valenta diesels [1,523 shp] Voith-Schneider propulsion, 2 bow thrusters. Speed 13 kts. Armament: 1 30mm. 2 mini guns 3 GPMG.

The seven remaining vessels are based at Faslane, and constitute the First Mine Countermeasures Squadron. HMS Grimsby has, in her recent refit, received a new sonar outfit [Type 2093] allowing her to find mines and underwater explosives with more clarity and at greater distances. Because of the small size of hull, the device is fitted into a towed body of one metre diameter, which is lowered beneath the vessel, giving the ship the ability to locate mine like objects depths as it penetrates temperature layers in the water. All of the class will be upgraded between 2019 and 2023.

Both classes use Seafox [also used by the USN] which is a small remote-controlled submersible which is deployed to identify mine-like objects, located by the ship’s sonar, sending back TV images back to the parent’s operations room.

Currently on station in the Gulf are the following:

Hunt class: HM Ships Brocklesby and Ledbury

Sandown class: HM Ships Blyth and Shoreham

RFA Cardigan Bay [Naval Party 1023 Forward Support Unit.


Described here is an example of a recently completed exercise involving an exercise minefield in the region in which the RN operated with helicopters of the USN in a mine sweeping exercise. The

aircraft involved were MH-53 Sea Dragons, 100 feet long and 33 tonnes full loaded. These aircraft haul a mine sweeping sled through the water to cope with moored mines and in this instance the sled was on board RFA Cardigan Bay. It was floated out of the dock, towed into position and then attached to the parent aircraft by cable to be subsequently towed through the water to detect magnetically sensitive mines. HM Ships Ledbury, Blyth and Shoreham also participated along with USN Avenger class hunters.

RFA Cardigan Bay acts as HQ/Depot ship to RN, USN and French MCM assets in the Gulf, providing food, fuel, ammunition and spares. Whilst also acting as the home of the UK mine warfare battle staff.


This subject matter is included for information, however readers must remember that we are looking at a situation which exists right now, and whether these techniques could be deployed today must be open to question, as it is not known how many systems exist at the time of writing.

Last year the RN was testing the first autonomous system available to it designed to deal with the latest technology mines. A small motor boat [Hussar] can be deployed on missions using a number of high technology boats trailed behind the parent craft to detonate the latest underwater explosive devices. Four months of initial trials were conducted in 2018 with the system being handed over to an RN specialist evaluation team to determine how best in might be used in action.

Hussar is an 11m long “command boat” which is followed by a series of small Coil Auxiliary Boats [CABs]. The CABs are designed to replicate ship signatures to trigger mines. If the trials continue to be a success, it is proposed to invest in four Hussars and their associated equipment. After basic signature trials, it was stated that the intention was to send units to the Canadian Arctic for cold weather operations, and then to the Gulf for warm water trials. Nothing is at present known about the success or otherwise of these proposals.


The mining of tankers in the Gulf, the detention of the VLCC Grace 1 by the UK and her subsequent detention in Gibraltar and the “disappearance” and subsequent detention by Iran of a UAE owned oil tanker has led to an escalation of tension in the region between the West, and in particular the United states and the United Kingdom resulting in a serious threat to commercial shipping entering and exiting the Gulf through an internationally recognised separation zone located in the Strait of Hormuz. The situation has been further exacerbated by the seizing, in international waters of the London registered Stena Impero inbound to Ras Tanura and interference with a UK owned Liberian registered VLCC on 19th July. The UK government’s response has been to advise UK flagged shipping to avoid the area, a somewhat impractical piece of advice.


Iran has a number of options available to it. Their armed forces could randomly lay mines in the strait, a body of water which is only 21 miles wide in places. Doing so would effectively close theGulf preventing both entry and exit to shipping. The country could indicate that it had laid mines in the strait. This would of course lead to the need by MCMVs to ascertain if indeed mines had been laid. Assuming this activity could be safely conducted, the strait would be closed until a safe route known to be clear of any mine-like objects was established. A third option might be to declare a minefield laid in such a manner to make shipping pass close to the Iranian coast, thus making the detention of vessels easier for the Iranian forces. As a colossal quantity of oil and gas passes outbound on a daily basis, this would enormous disruption to both shipping and third-party economies. However, any of these activities might in themselves hurt Iran by preventing that state to export its own oil.

As a result of this factor, Iran might choose, in concert with its allies in Yemen, to mine the Bab el Mandeb strait. This would effectively seal off the Red Sea and prevent shipping from using the Suez Canal. To reach Europe vessels would require to be routed round the Cape of Good Hope, adding weeks to the voyage, with all the associated costs that would involve. Should this take place, mine countermeasures forces would require to be deployed to the region. Aden would seem to be the natural choice as the port has a deep-water container port and suitable jetties and other facilities. However, security would be a problem as Houthi rebels have over the past decade caused serious damage in Aden city. Other possibilities for a base might be Djibouti or the island of Socotra which belongs to Yemen, and has a paved airfield capable of taking aircraft of the size of a Boeing 737 or Airbus 319/320, and so could operate mine sweeping helicopters.

A map showing Bab el Mandeb follows for information

United Nations Convention on the Law of the Sea (UNCLOS 82) and its Implications

There has already been a number of incorrect comments and assumptions made about warships and the territorial sea of a state. It therefore worth noting what the Convention actually states in this context. Article 19 of the convention defines the right of innocent passage through the territorial sea by vessels other than those of the coastal flag state. The following UNCLOS Articles relate to warships and other government owned ships [the RFA, for instance] operated for non-commercial purposes, and are quoted verbatim.

Article 29

Definition of warships

For the purposes of this Convention, “warship” means a ship belonging to the armed forces of a State bearing the external marks distinguishing such ships of its nationality, under the command of an officer duly commissioned by the government of the State and whose name appears in the appropriate service list or its equivalent, and manned by a crew which is under regular armed forces discipline.

Article 30

Non-compliance by warships with the laws and regulations of the coastal state

If any warship does not comply with the laws and regulations of the coastal State concerning passage through the territorial sea and disregards any request for compliance therewith which is made to it, the coastal State may require it to leave the territorial sea immediately.

Article 31

Responsibility of the flag State for damage caused by a warship or other government ship operated for non-commercial purposes

The flag State shall bear international responsibility for any loss or damage to the coastal State resulting from the non-compliance by a warship or other government ship operated for non-commercial purposes with the laws and regulations of the coastal State concerning passage through the territorial sea or with the provisions of this Convention or other rules of international law.

Article 32

Immunities of warships and other government ships operated for non-commercial purposes

With such exceptions as are contained in subsection A and in Articles 30 and 31, nothing in this Convention affects the immunities of warships and other government ships operated for non-commercial purposes.

Part III of the Convention covers the use of Straits for International Navigation and can be studied by those wishing to acquaint themselves with these rules.



The answer is that the combined USN, RN and French assets, both rotary wing and surface, are probably sufficient to deal with mining in the region. However, the question is, would it be possible to conduct these operations in the face of a hostile and unpredictable enemy. Mine hunting from a ship is of necessity a slow process requiring a painstaking search involving remote vehicle for identification of mine-like objects, and the use of remote vehicle or clearance divers to destroy the ordinance. Similarly, large helicopters flying close to the surface and towing mine sweeping sleds present a vulnerable target for missiles to bring down. Threats exist from Swarm attacks by multiple manned or un-manned fast attack craft, and there is a constant danger of mini submarine strikes which could easily sink an on-task MCMV. Force protection would therefore be very difficult to achieve, and it is probable that mine clearance could not take place until diplomacy was in place to resolve the issue. That said, it would seem unlikely that the Iranians would in the current circumstances do anything other than lay a declared field in such a way as to benefit their own agenda. However, anything seems possible with the Revolutionary Guard, who in turn takes orders from the supreme leaders.