HMS Arun (M2014): The Minesweeper Reassigned to Patrol Northern Ireland's Waterways

Built to Sweep Soviet Mines

HMS Arun was a River-class minesweeper, one of twelve built by Richards Shipbuilders at Lowestoft and Great Yarmouth, launched in 1985 at a cost of roughly £4.6 million each.

Displacing 850 tons and crewed by around 28 officers and ratings, the class was built with steel hulls based on commercial offshore support vessel designs, intended to operate as deep-sea team sweepers capable of countering Soviet deep-water moored mines using the Wire Sweep Mark 9 system, which combined mechanical wire-cutting with acoustic and electromagnetic influence sweeping.

The most interesting thing about the class is who was meant to crew them. Eleven of the twelve went to Royal Naval Reserve divisions around the country, one apiece, with only Blackwater going to the regular fleet, and they joined the 10th Mine Countermeasures Squadron at Rosyth. They were, in other words, the direct successors to the reserve Ton class minesweepers that had spent thirty years taking part-time sailors to sea at weekends. Same idea, newer hull: give each division a real commissioned warship of its own, and keep several hundred civilians in practice at a skill the country would need a great deal of in a war and could not possibly improvise.

What they were for is worth explaining, because it is a very specific problem. The Soviet Union had a deep buoyant moored mine designed to sit far below the surface, well out of reach of anything sweeping for ordinary shipping, and intended to catch submarines and heavy ships passing through the deep water of the gaps between Greenland, Iceland and Scotland. Clearing those needs a wire towed at depth between two ships steaming in company, which is why the equipment is called an Extra Deep Armed Team Sweep and why the ships were built in a batch of twelve rather than as individual hunters. One of them on her own is not much use. Six pairs of them working a channel is exactly what the Atlantic reinforcement route would have needed.

Arun herself was laid down on 4 February 1985 at Richards' Lowestoft yard as Yard No. 571, launched that August, and completed in May 1986. She was powered by two Ruston 6RKCM diesel engines driving twin shafts, giving a modest top speed of around 14 knots and a range of roughly 4,500 nautical miles at a 10-knot cruise, more endurance than most of her working life would ever actually call for.

For self-defence she carried a single 40mm Bofors gun on an old World War II-era mounting alongside two general-purpose machine guns, a modest armament for a ship whose real value lay in her specialist equipment rather than her firepower. Like all her sister ships, she took her name from a British river, in her case the Arun, which rises in the Sussex Weald and reaches the English Channel at Littlehampton.

A Very Different Kind of Patrol

Rather than spending her whole career hunting mines in open ocean, Arun was, from 1993, one of four River-class vessels, alongside Blackwater, Spey and Itchen, assigned to the Northern Ireland Squadron, where they replaced the older Ton-class minesweepers patrolling the province's loughs and inland waterways during the Troubles.

The squadron she joined had been doing that job since 1969 and had a particular character by the time she arrived. It worked from a jetty in the Musgrave Channel in Belfast Harbour, next to Moscow Camp, and much of what it did was in the border loughs, where the frontier runs down the middle of the water and a boat can be in a different jurisdiction in half a minute. Alongside the interdiction work went a great deal of straightforward support for the Army and the Royal Ulster Constabulary: moving people and stores to places the roads could not safely reach, and watching stretches of water that could not be watched from land. The fuller picture is in the articles on HMS Itchen (M2009) and HMS Blackwater (M2008), both of which were doing it alongside her.

The squadron's job was to interdict the seaborne movement of illegal arms and provide wider material support for anti-terrorist operations, close cooperation with the British Army and the Royal Ulster Constabulary that made for unglamorous, watchful, close-quarters work rather than the open-ocean specialist mission the class had originally been designed around.

Which is how a deep-ocean minesweeper ended up in Carlingford Lough. The Northern Ireland Squadron's work was slow, close and entirely unlike anything in the ship's design brief: watching the loughs and the coast, stopping and searching small craft, working alongside soldiers and RUC officers, and being visibly present in water where the alternative was that nobody was watching at all. A shallow-draught, steady, unglamorous hull with a good radar, a long endurance and a boat is very well suited to that. The Bofors on the forecastle, mounted on a Second World War carriage, was almost entirely beside the point.

They were also, unluckily, the last word in a technique that was on its way out. Sweeping works against a mine that is moored to the bottom and detonated by contact or by a simple influence fuse. It does not work against a modern ground mine, which sits on the seabed, listens, counts ships passing and fires when it chooses. The answer to that is minehunting: find the object with high-definition sonar, look at it with a remotely operated vehicle or a diver, and destroy it where it lies. By the 1990s the Royal Navy had committed to hunting, and twelve very capable deep sweepers found themselves without the war they had been built for.

There is a second reason these four ships were available for Northern Ireland in 1993, and it is the more consequential one. That year a review of the Royal Naval Reserve withdrew all eleven of the River-class minesweepers assigned to its divisions at a stroke, which took away the sea-going Reserve's only real training tool. A Ton or a River was about the smallest ship in which an officer or rating can genuinely learn ship handling, navigation, working in company, signals, firefighting, damage control and gunnery, and none of that can be taught properly ashore. When the ships went, the divisions kept their people and lost the thing that made them sailors, and the Royal Naval Reserve became a reserve of specialists who augment the fleet rather than a body that takes its own ships to sea. What that decision looked like from the ship's side is set out in the article on HMS Carron (M2004). Arun was one of the four that were found another job. The other eight were sold.

Arun and her three sisters held that role for around five years, until Hunt-class mine countermeasures vessels took over Northern Ireland Squadron duties in 1998.

The 1998 handover to the Hunt class was not a demotion either, and it says something about how the Ulster job had changed. A Hunt is a bigger, better-equipped and considerably more expensive ship than a River, with a glass-reinforced plastic hull, a proper minehunting sonar and remotely operated vehicles, and putting one on constabulary patrol in a lough is using a scalpel to open letters. But by 1998 the Good Friday Agreement had been signed, the squadron's task was winding towards its end rather than expanding, and the Navy had Hunts available where it no longer had Rivers. The squadron kept going for another seven years on that basis; its disbandment was announced on 23 March 2005 and the last three Hunts paid off that July, thirty-six years after the first ships had been sent across. It ended because there was nothing left to do, which is the only good reason for a naval commitment to end.

A New Life in Brazil

Arun was eventually sold to the Brazilian Navy in September 1998, and went on to be renamed not once but twice in her new service, successively becoming Hercules, then Jose Bonifacio, and finally Babitonga.

That string of names reflects a particularly long and evidently useful second career, a fairly common pattern for the sturdy, adaptable River-class hulls once the Royal Navy had moved on to more specialised minehunters, and a fitting afterlife for a ship whose Royal Navy years had already taken her somewhat off-script, from anti-Soviet mine warfare to patrolling the rivers of Northern Ireland.

The Brazilian purchase is more interesting than a sale for scrap value. Brazil bought four of the class in 1998 and originally intended them as buoy tenders, servicing the navigation marks along an enormous and busy coastline, which is a perfectly sensible use for a steady, roomy, long-legged hull with deck space and a crane. In practice the Brazilian Navy found them more useful as patrol vessels and reclassified them accordingly. As NPa Babitonga, pennant P-63, Arun is based at the port of Rio Grande in the far south of the country and works the coasts of Rio Grande do Sul, Santa Catarina and Paraná. Her job is inspection, safety of life at sea and surveillance of Brazilian territorial waters, which is to say fishery protection, search and rescue and sovereignty patrol: almost exactly the work the Royal Navy's own Fishery Protection Squadron does, in a different ocean, in a ship built to sweep Soviet mines out of the Denmark Strait.

The three names are worth a word, because a ship being renamed twice in one navy is unusual. Brazilian practice, like British, attaches names to roles as much as to hulls, and a vessel that changes what she is for often changes what she is called: Hercules is a name for a working vessel, José Bonifacio commemorates one of the founders of Brazilian independence, and Babitonga is a bay on the coast of Santa Catarina, which is the sort of name a patrol ship working that stretch of water would properly carry. The sequence is really the record of a navy working out what it had bought. She was acquired as one thing, tried as another and settled as a third, and she has now been Brazilian for longer than she was ever British. A hull laid down at Lowestoft in February 1985 has spent about a dozen years under the White Ensign and nearly thirty under the Brazilian flag, and she is still working.