HMS/M Tetrarch

Lt Cdr R.G. Mills in Tetrarch had hit a large troop transport in the Skagerrak in April 1940. As soon as the torpedoes left the tubes, Mills took the Tetrarch deep, for the transport had an escort of three destroyers and they were quick to counter-attack. As the submarine was still on her way down, the first depth charges began to explode.

But already conditions in the Tetrarch were bad. On the previous night she had been put down while charging her batteries and kept down during the remainder of the dark hours. In consequence, her battery power was low, the air inside her was already very foul and the air pressure in the boat was mounting from the unavoidable small leaks in the high pressure air system.

The destroyers continued to hunt for three hours and, when they gave up, their place was taken by a flotilla of anti-submarine trawlers. Try as she would, the Tetrarch could not get clear, the hunting boats following her every movement.

The hours of daylight passed, but even the darkness brought no relief from the hunt. The high pressure in the boat and the foul air were getting dangerous and Mills decided to bring the Tetrarch up, in the hope that she could steal away unseen in the darkness. Because of the great pressure in the boat, and its sudden escape when the conning tower hatch was opened, Mills detailed the heaviest member of the crew to hang on to his legs when he knocked the clips off, for fear of being blown out of the boat. Even with this additional weight, he was lifted up by the escaping air.

As soon as she was on the surface, the Tetrarch was sighted by the trawlers. Mills had time to fire two torpedoes, set to run shallow, "to discourage their approach" as he said in his patrol report, but this was not enough to deter them. Within two minutes of surfacing, the Tetrarch was down again. The pressure inside her was normal now, but there had not been time to ventilate the boat and the foul air remained.

The Tetrarch reached 300 feet before the first charge exploded. Others came down with great frequency, and the boat was badly shaken. The disturbance caused in the water upset her trim and she began to "porpoise" between 400 feet and periscope depth, once breaking surface and giving away her position. Within a few seconds she was down again at 350 feet and there she managed to catch a perfect trim, lying stopped in the water and neither sinking nor rising.

She was, in fact, lying on a heavy layer of water and this proved her salvation. The heavy layer was caused by a sub-surface current which was setting in the opposite direction to that above. Slowly the two were being carried further apart, the hunting trawlers in one direction, the hunted Tetrarch in the other.

The men in the submarine lay silent, trying to conserve the oxygen in the boat. Below the deck, the batteries were getting weaker, the last of their power being slowly used up. There was no chance now of coming up to the surface and recharging the batteries, for the night was fast passing, and the foul air would have to remain, and get fouler, throughout the hours of another day.

Shortly before noon the Tetrarch came up to periscope depth. A look-round showed that the hunt had given up, as the sea was empty. But there was still no chance of coming to the surface, for the boat was right in the track of the German air traffic to Norway and to be sighted by an aircraft would inevitably mean the return of the hunting ships. So, remorselessly, she went deep again, to use the last dregs of her battery power in a slow crawl towards safer waters.

That night, at 2130, the Tetrarch again came to the surface. She had been under, apart from two minutes the previous night, for 42 hours and 40 minutes. As she broke surface and opened her hatch, the commanding officer and look-outs searched the sea anxiously. There was nothing in sight, and the Tetrarch's ordeal was over. Many of the crew were violently sick as the foul air was replaced, all were dizzy, but recovery was rapid and the submarine was able to complete her patrol before returning home in safety.

The Womens Institute in the village of Mayfield, East Sussex, hold Tetrarch in memory:

The following letter appeared recently (2002) in the Womens Institute magazine:

"In this year of memories, our WI, Mayfield (Afternoon), East Sussex, has been proud to maintain the memory of HMS Tetrarch, a Royal Navy submarine which we adopted during the Second World War. After successful operations off Norway, it was lost with all hands in October 1941.

A watercolour by a local artist, together with a small, framed history, hangs in the Memorial Hall where we hold our meetings and a Roll of Honour and a plaque are sited in an alcove in our parish church St Dunstan’s. One of our members at the time who lost a brother in naval action donated a vase for the alcove and fresh flowers have been provided for it every week since then. We understand that Mayfield is the only village to keep this tradition in memory of a ship’s company. The undertaking has always been a joy and a privilege.

A visitor to the church who had served on HMS Tetrarch was amazed and delighted to find that the memory of his gallant vessel was being kept green. If anyone can give us any further information about the ship, or knows anyone who served in her, we should be pleased to hear from them.”