HMS Sea Devil (P244): Reaching Malta the Day the War Ended

Built on the Clyde for a War Nearly Over

HMS Sea Devil was built by Scotts Shipbuilding and Engineering at Greenock, laid down on 5 May 1943, launched on 30 January 1945 and commissioned that May, an Improved S-class submarine that spent her first weeks of service on degaussing trials, torpedo discharge tests and anti submarine exercises in Scottish waters.

She sailed for the Mediterranean that August, reaching Gibraltar by the tenth of the month and Malta on 15 August 1945, the exact day Japan's surrender was announced, bringing her intended active deployment to an immediate and rather anticlimactic close before it had properly begun.

The precision of that is worth sitting with. She left the Clyde in August 1945, made Gibraltar on the tenth, and came into Grand Harbour on the fifteenth, which is the day the Japanese surrender was announced. Her ship's company will have secured alongside to the sound of every siren in Malta going off at once. Whatever they felt about it, and it will not have been simple, their war was over before it started.

She has a good deal of company in this queue. HMS Scorcher missed it by a week, HMS Sentinel was not finished until December 1945, and HMS Talent reached Hong Kong four months after the surrender. Britain spent enormous effort building submarines that arrived just as they stopped being needed, which is what happens when a war ends faster than a shipbuilding programme can be turned off.

No record of any combat action, sinking or attack involving Sea Devil survives in any source consulted, a genuine and complete gap in her wartime record rather than any oversight.

That is an unusually honest sentence and it deserves supporting rather than filling. A great many naval histories will quietly imply activity where there was none, and the truthful position here is that Sea Devil never attacked anything, because there was nothing left to attack by the time she was ready.

What she did instead was real work even if it produced no tally. Degaussing trials are about reducing a hull's magnetic signature so that magnetic mines do not detect it, which is a matter of life and death and generates no headlines. Torpedo discharge tests establish that the weapons leave the boat properly. Anti-submarine exercises mean acting as the quarry so that escort crews learn their trade. None of it makes a story and all of it had to be done by somebody.

A Quiet Decade in the Mediterranean

Refitted and recommissioned for a second time in April 1951, Sea Devil went on to spend much of the following decade based in the Mediterranean, her service there beginning around the mid 1950s.

She is also said to have taken part in trials of an early infrared system nicknamed Yellow Duckling, intended to help detect the wakes left by submerged submarines, an interesting if lightly documented footnote to her otherwise unremarkable peacetime career.

Yellow Duckling, and the Attempt to Make Submarines Visible

That footnote is the most interesting thing in her whole record and deserves opening up, because Yellow Duckling was a serious attempt to solve the central problem of anti-submarine warfare by going round it entirely.

Sonar has a fundamental limitation: to hear a submarine you must be reasonably close to her, and the ocean is enormous. What everybody wanted was a way of spotting a submerged boat from an aircraft, quickly, over a wide area. The idea behind Yellow Duckling was that a submarine moving under the surface disturbs the layers of water above her and drags slightly cooler water upwards, leaving a faint thermal trace on the surface that a sensitive enough infrared detector might see from the air.

The equipment, trialled from about 1953 to 1956, was built around a lead telluride detector element about six millimetres square, adapted from an infrared seeker developed for shooting down aircraft. To function at all it had to be cooled with liquid nitrogen to seventy-seven degrees above absolute zero, which in a 1950s maritime patrol aircraft was not a trivial request.

The name needs explaining too, because Yellow Duckling sounds like a joke and is not. British defence projects of the period were given deliberately meaningless two-word codenames from a system known as the Rainbow Codes: a colour and a noun, picked at random so that the name gave nothing away. It produced Blue Streak, Red Beard, Violet Club, Green Cheese and Blue Lagoon, the seeker this detector came from. Yellow Duckling is exactly as serious, and exactly as uninformative, as it was meant to be.

It did not work well enough. The thermal signature a submarine leaves is extremely faint, it is smeared by wind and sea state, and the sun heating the surface swamps it for much of the day. Sonar remained the answer, and the whole of the Cold War underwater contest was fought on acoustics, which is why the quietness of boats like HMS Oberon mattered so enormously.

It is worth noticing what her part in it actually was, because it is the opposite of glamorous and entirely characteristic of her. Somebody has to be the submarine. A programme trying to find out whether a submerged boat can be seen from the air needs a submerged boat to look for, running at known depths and speeds on known courses, over and over, while an aircraft flies patterns above her and the scientists aboard argue about whether the trace on the instrument is a submarine or a cloud shadow.

The idea never quite went away, though. Navies have kept working at non-acoustic detection ever since, and the arrival of far better sensors and satellite coverage has made it a live question again. If a submarine ever does become reliably detectable from the air, the argument will have been won by the descendants of a device with a silly name that a handful of British boats spent the mid-1950s being hunted by.

The End of Her Service

HMS Sea Devil was paid off at Portsmouth on 4 June 1962 and sold to a shipbreaker, arriving at Newhaven for scrapping that December, with the physical breaking up of the vessel apparently following in early 1966, some months after her arrival.

It is a quiet, workmanlike record for a submarine whose entire wartime story amounted to a single voyage cut short by the very peace she had been built and trained to help secure.

There is one small oddity in the ending worth pointing at. She was sold and reached Newhaven in December 1962, and the actual breaking up appears not to have happened until 1966. Three years is a long time to sit in a scrapyard, and it usually means one of two things: either the price of steel had fallen far enough that the breaker was in no hurry, or somebody was still deciding whether there was a use for her. Either way she spent longer waiting to be cut up than she had spent in her first commission.

Seventeen years, no shots fired, and a share in an experiment that tried to make her whole profession obsolete. It is not the career anybody at Greenock was imagining when they laid her down in 1943, and it is a good deal more typical of naval service than the records that get written up.