British would-be submarine commanders tested to limit by HMS Sutherland and 814 NAS.

British sailors, submariners and naval aviators are pitting themselves against each other off Scotland to pick commanders for the UK’s ultimate military mission. Frigate HMS Sutherland and her Merlin helicopter plus one submarine are committed to Perisher – the demanding course which determines whether prospective commanders have the ‘right stuff’. Those who pass the assessment will go on to command submarines carrying the nation’s nuclear deterrent – or the hunter-killer submarines used to protect them from hostile threats.

HMS Sutherland frigate (Picture source: Royal Navy)

Much of Perisher – officially the Submarine Command Course – takes place in classrooms and simulators ashore as an experienced skipper, known as ‘Teacher’, and his staff put a select group of officers through their paces over several months. For the final few weeks, the course shifts to a submarine with real warships posing as adversaries to give the students ­and the hunters a thorough workout in shallow, confined waters and the open ocean.

For HMS Sutherland – aka The Fighting Clan – anti-submarine warfare demands near-total silence and total concentration. The Plymouth-based frigate runs out (or ‘streams’) her towed array sonar – a long tube which is unrolled from the stern and either listens for a submarine lurking below, or actively by ‘pinging’, sending sound waves through the depths, hoping to strike a boat’s hull, more effective… but it also gives the warship’s location away.

Aboard, crew walk around in socks, keep noise to an absolute minimum – mainly by retiring to their bunks, leaving only those absolutely needed to operate the ship safely and the operations room team hunting the submarine on duty.

Hand-in-hand with Sutherland’s hunt, her Merlin helicopter drops sonobuoys – listening devices – in the ocean and, to pinpoint a submarine’s position, hovers and lowers a ‘dipping sonar’. If successful, the aircraft’s crews either drop depth charges or, more likely, launch Sting Ray torpedoes to eliminate the threat.

However the hunters do not merely have to locate the submarine, they have to bear in mind how salty the water is, how deep it is and its temperature among other variables – all of which have a marked impact on the effectiveness of sonar. “Playing the submarine’s enemy, the ship and Merlin provide a powerful anti-submarine warfare capability which makes it extremely difficult for the submarine to evade and complete its missions”, said Lieutenant Commander Tim Strickland, the Merlin Flight Commander aboard HMS Sutherland.

The helicopter is normally based at Culdrose Air Station in Cornwall with 814 Naval Air Station and is supported by a 14-strong team of aviators, technicians and engineers. The latter have to maintain the Merlin in the cramped confines of the ship’s hangar, day and night, as HMS Sutherland pitches and rolls. “We've had to do some pretty big jobs on the aircraft and some of them are things that none of us has ever done embarked, so they took a bit of planning, but we have to do them if the helicopter is to remain available to fly,” explained Air Engineering Technician Jensen Hoyland, the youngest member of the flight.

Both the helicopter crew and the ship’s dedicated submarine-hunting team have relished the opportunity to ‘play’ with a live ‘foe’. “While there always has been an intense – but friendly – rivalry between the surface and submarine fleets, there also has been a large amount of professional respect and admiration,” said Lieutenant Commander Dan O’Connell, HMS Sutherland’s principal underwater warfare officer.

“Being an active part of Perisher has been a great opportunity for the Fighting Clan to test herself against the best potential submarine commanders that the Royal Navy has to offer, and allowed Sutherland to remain at the cutting edge of anti-submarine warfare. We hope that we have provided adequate opposition to the submariners – and helped to maintain the reputation of Perisher as the hardest and most realistic submarine command course in the world.”

The course’s nickname either derives from periscope – or from the ‘perishing’ drop-out rate. Typically, fewer than half of the prospective submarine commanders make the grade.