HMS Snapper (39S): The Bombing Test That Changed Anti-Submarine Warfare

Constructed at Chatham

HMS Snapper was built at Chatham Dockyard, ordered on 12 June 1933, launched on 25 October 1934 by Lady Tweedie, and commissioned on 14 June 1935, a second-batch S-class submarine of 670 tons displacement that went on to complete fourteen war patrols between November 1939 and February 1941, chiefly in the North Sea, the Skagerrak and the Bay of Biscay.

Thirteen of those fourteen patrols were commanded by the same man, and he is worth knowing about. Lieutenant William Donald Aelian King took Snapper in April 1939, four months before the war started, and was twenty-nine years old. He is better remembered as Bill King, and his obituaries credit him with something no other British officer managed: he began the war in command of a submarine and was still alive and in command of one when it ended in August 1945.

That sounds like a modest distinction until the arithmetic is done. The Royal Navy lost seventy-four submarines in the Second World War, and a captain who was still doing the job six years later had beaten odds that killed most of the men who started alongside him. He went on to command HMS Telemachus in the Far East, and afterwards had a second life that has nothing to do with submarines at all.

An Accidental Discovery

In December 1939, Snapper was mistakenly bombed by a British aircraft while returning to Harwich, an alarming friendly-fire incident that nonetheless produced a useful result: it demonstrated that the standard 100lb bombs then carried by RAF aircraft were essentially useless against submarines, a discovery that directly informed the later development of more effective anti-submarine weapons.

Four Broken Light Bulbs

The detail is what makes it, so here it is. On 3 December 1939 an Avro Anson of 206 Squadron, Coastal Command, found a submarine in the North Sea off the Dutch coast, identified her as a U-boat and attacked. The crew got a direct hit on Snapper's conning tower with a 100lb anti-submarine bomb.

The total damage was four broken light bulbs in the control room.

The aircrew went home and reported a successful attack on a U-boat, which is entirely understandable and entirely wrong, and the giveaway is that no German submarine recorded being attacked from the air anywhere that day. What the Admiralty and the Air Ministry had instead was something more useful than a kill: an unambiguous, fully documented test of their principal anti-submarine weapon against a real submarine, with a British crew available afterwards to describe exactly what it had felt like.

The answer was that it had felt like almost nothing. The 100lb bomb simply did not carry enough explosive to matter, and a bomb that goes off on or just under the surface wastes most of what it does carry into the air. Water does not compress, so a charge that detonates against a hull is lethal and one that detonates a few feet away in the air is a loud noise. The RAF had been flying the Atlantic and the North Sea for three months carrying a weapon that could not have killed a U-boat if it had hit one.

What replaced it was the airborne depth charge: a naval depth charge adapted to be dropped from an aircraft, with a far larger charge and a pistol set to fire at a shallow depth underwater rather than on contact. That weapon, refined through the war with better explosives and better fuzing, is what eventually made aircraft the most effective U-boat killers of the whole campaign. Snapper did not win the Battle of the Atlantic, but she did provide the experiment that showed the weapon had to change, and she did it by being hit.

A Productive War

Under Lieutenant W. D. A. King for her first thirteen patrols, Snapper built up a substantial tally of successes in April 1940 alone, sinking the German tanker Moonsund on 12 April, the merchant vessel Florida two days later, and two German minesweepers, M 1701, or H.M. Behrens, and M 1702, or Carsten Janssen, on 15 April.

Four ships in four days needs its context, because it was not a lucky fortnight. Germany invaded Norway on 9 April 1940, and every available British submarine was flung into the Skagerrak and the Kattegat to cut the sea route the invasion depended on. For about three weeks those narrow, shallow, heavily patrolled waters held the densest concentration of targets and of danger that British submarines saw in the entire war.

Florida, the ship she torpedoed on 14 April, was 6,148 tons, which makes her far and away the largest thing Snapper ever sank and larger than everything else on her list put together.

The bill for that month was severe. HMS Sterlet sank a German gunnery training ship in the Skagerrak in mid-April and never came home. Several other boats went the same way in the same few weeks, and the campaign that all of it supported was lost anyway. King brought Snapper through it with four ships to her name, which in April 1940 counted as a very good month indeed.

She went on to sink the German armed trawler V 1107 and the Norwegian merchant Cygnus in June and July 1940. Earlier, on 6 May, she had attacked the German armed merchant cruiser Widder, though her torpedoes missed their target on that occasion.

That miss is the one that mattered, and the timing of it is remarkable. Widder was an armed merchant raider of 7,851 tons, a converted cargo ship disguised as a neutral and fitted with concealed guns and torpedo tubes, and 6 May 1940 was the day she left German waters to begin her raiding cruise. Snapper found her on her first day out and fired two torpedoes at her. Both missed.

Widder spent the next six months in the Atlantic and sank or captured ten ships totalling something over fifty-eight thousand tons before engine trouble sent her home. She made harbour on 31 October 1940, at Brest.

Which is where this becomes uncomfortable. Brest is almost certainly where Snapper died, three months later. Two torpedoes running a few yards wide in the Kattegat cost ten merchant ships and their crews, and the raider they failed to stop went to ground in the exact stretch of water that killed the submarine which had fired them.

Lost with All Hands

Snapper departed on her fourteenth and final patrol on 29 January 1941, now under the command of Lieutenant Geoffrey Vernon Prowse, bound for the Bay of Biscay. She failed to make her rendezvous with the escort vessel HMS La Capricieuse on 12 February and was never heard from again.

The most widely credited account holds that she was detected attacking German minesweepers near Brest on 10 or 11 February and was sunk by a sustained depth-charge counterattack, though the loss of a British mine has also been suggested.

The German case is specific enough to take seriously. On 10 and 11 February 1941 the minesweepers M-2, M-13 and M-25 were attacked by a submarine off Brest, hunted her, and put fifty-six depth charges down on the contact. Snapper had been ordered to remain on patrol until 10 February and then start for home, which puts her in the right water at the right hour, and she failed to meet her escort off the Scilly Isles on the 12th. She was declared overdue on 14 February 1941.

The British mine is the alternative and it is not a far-fetched one. The Royal Navy laid extensive fields in the approaches to the Biscay ports to bottle up exactly the traffic Snapper was there to attack, and the fields moved, drifted and were not always where the chart said. More than one British submarine was lost to British mines during the war, and nobody ever knows, because a mine leaves no witness on either side.

Fifty-six depth charges is a great many. It is also worth saying that a boat can survive that and be lost the following week to something else entirely. The honest position is that the German attack is the best-documented candidate and that it has never been confirmed, and no wreck has been found.

Either way, all 41 of her crew were lost, a heavy and permanent silence that closed the book on a boat that had fought hard and well for over a year.

She is one of a long list from those waters. HMS Seahorse disappeared north-west of Heligoland in the first winter of the war, and HMS Sturgeon, a sister working the same patrol lines, scored the first British submarine kill of the war, went on to serve the Dutch as Zeehond and was still afloat in 1947. The difference between the two outcomes is mostly luck, and everyone involved knew it at the time.

There is one last thing worth setting down. Bill King handed Snapper over on Christmas Eve 1940 and went to another boat. Prowse took her out five weeks later and neither he nor she came back. King lived to a hundred and two. Nothing about that is a judgement on either man, and it is the plainest possible illustration of what the submarine service was: the same boat, the same ocean, the same job, and an outcome nobody had any control over whatever.