Submarine hunters on HMS Northumberland honed their skills during a four-day ‘fight’ in the fjords.
The Plymouth-based frigate tested her mettle against the Norwegian Navy – in waters its submariners know like the back of their hands.
Ahead of her security duties at the G7 summit in Cornwall, Northumberland was invited to join the hosts for Exercise Grüner Aal, played out in the confined waters around Bergen.
The war games provide a key training environment for the Norwegian Navy to practise live firing of torpedoes at various depths against realistic manoeuvring targets… and for surface vessels to practise their counter-measures.
The pandemic limited participation this year from international vessels, but Northumberland was able to join the host’s support ship Magnus Lagabøte, tug HS4 Mjølner.
Doing its best to get Northumberland in its sights was the diesel-electric submarine HMNoS Uredd.
She’s tiny by comparison with Britain’s hunter-killer boats – but operating in home waters with a highly-skilled crew of only 21, being a small and very quiet submarine, she was an elusive target.
To find something which is small, quiet, submerged and doesn’t wish to be found, Northumberland sent sound waves through the depths as she tested both her hull-mounted and towed-array sonar systems – and also switched to silent running to passively listen for the ultra-quiet submarine.
That tests not just the skills of the sonar operators in the operations room, but the entire ship’s company, who have to minimise all noise aboard – even down to removing shoes.
And the frigate pulled out the ace up her sleeve in the form of her Merlin Mk2 helicopter.
Mohawk Flight from 814 Naval Air Squadron at Culdrose used her sonobuoys (listening devices dropped in the ocean) and her ‘dipping’ sonar, lowered beneath the Merlin, to locate and successfully track the Uredd’s movements throughout the exercise – and conducted simulated attacks to defend Northumberland.
With the exercise done, Uredd showed herself on the surface and Mohawk Flight was launched again – this time taking shots as pilot Lieutenant Matt Le Feuvre captured hunter and hunted on camera.
Captain Bård Hess, in charge of the Norwegian Navy’s 1st Submarine Squadron, said the Northumberland and Uredd were well-matched foes with the Britons demonstrating a “high level of training” while their ship proved hard to locate due to how quiet the dedicated submarine hunter is.
“Uredd benefited greatly from training with HMS Northumberland,” he said. “An exercise at such a level raises the competence both for the individual, but also for the entire organisation which must deal with a possible threat.
“Norwegian submarines are sought-after partners for foreign warships. The Ula class is quiet and difficult for frigates to locate.”
