At first the convoys outward-bound from Britain had been given RN escorts on only the first stage of their journey, about 15 degrees west longitude. Then the escorts stayed as far as 25 degrees west and then – by July 1941 – convoys were given continuous escort. Relays of escorts operated from Britain, from Iceland and from Newfoundland. But warships were scarce, so that even by the end of 1941 the average convoy had no more than two escort ships.
The escort ships were not immune to torpedoes either. I make no apologies for the extra length of this excerpt from one of the most graphic accounts the Atlantic battle provided:
The sky suddenly turned to flame and the ship gave a violent shudder … Looking ahead, I could see something floating and turning over in the water like a giant metallic whale. As I looked it rolled over further still and I could make out our pennant numbers painted on it. I was dumbfounded. It seemed beyond reason. I ran to the after-side of the bridge and looked over. The ship ended just aft of the engine room – everything abaft that had gone. What I had seen ahead of us had really been the ship’s own stem. There were small fires all over the upper deck. The First Lieutenant was down there organizing the fire parties. He saw me and called, ‘Will you abandon ship, sir?’ ‘Not bloody likely, Number One … We’ll not get out till we have to.’
But a ship with its stern blown away does not stay afloat for long:
The deck began to take on an angle – suddenly – so suddenly. She was almost on her side. I was slithering, grasping all kinds of unlikely things. My world had turned through ninety degrees … I jumped for the galley funnel which was now parallel with the water and about two feet clear, and flat-footed it to the end. I paused at the end of my small funnel to look at the faces. They were laughing as if this were part of some gigantic fun fair. The men called to me.
‘Come on, sir. The water’s lovely.’
‘I’m waiting for the Skylark,’ I shouted back. But the galley funnel dipped and I was swimming too – madly … We swam like hell. I turned once more, but now there were very, very few bobbing heads behind me. I swam on. The destroyer of my old group was passing through us. I could see her men at action stations. They were attacking. They were attacking the wreck of the Warwick! I screamed at them in my frenzy. Wherever else the U-boat might have been it could not have been there. The depth charges sailed up in the air. Funny how they wobbled from side to side, I’d never noticed that before. When, I wondered, would they explode? It was like being punched in the chest, not as bad as I had expected. I swam on. Things were a bit hazy. I was not as interested in going places as I had been. I could only see waves and more waves, and I wished they would stop coming. I did not really care any more. Then I felt hands grasp my shoulders and a voice say, ‘Christ, it’s the skipper. Give me a hand to get the bastard in,’ and I was dragged into a Carley-float which was more than crowded to capacity.19
To make the most of their pitifully few escorts, the RN had started ‘Escort Groups’, which usually meant in effect nothing more than RN captains getting together – under one of their number named as escort group commander – to exchange ideas about anti-submarine tactics.
It was the 5th Escort Group which in March 1941 was in the same area as the German navy’s three most famous U-boat captains: Günther Prien, Joachim Schepke, the celebrated and colourful captain of U-100, and Otto Kretschmer of U-99. At their collars these men wore the Ritterkreuz, to which the insignia of the oak leaves had been added to celebrate 200,000 tons of ships sunk. Kretschmer and Schepke were both determined to be the first to sink 300,000 tons of Allied shipping. Kretschmer had left his base at Lorient credited with 282,000 tons (although, as we have seen, such German figures were usually very much inflated).
It was Prien in U-47 who sighted the outward-bound convoy OB 293 and summoned his colleagues: Kretschmer, Matz in U-70 and Hans Eckermann in UA.20 Although a primitive seaborne radar set played its part, this encounter marked little change in the methods or technology of either side. But there was a change in the men: the Germans, solidly professional, were at the zenith of over-confidence, while the Royal Navy’s landlubbers and weekend yachtsmen had discovered a new determination.
Kretschmer started the sinkings. Firing while surfaced, he hit a tanker which burst into flame and a Norwegian whaling ship Terje Viken which remained afloat. Using the same tactics in U-70, Matz hit a British freighter and the Mijdrecht, a tanker, which with true Dutch resilience steered at him and rammed as U-70 dived. The UA was detected and dived, its course followed by asdic. Depth charges damaged it enough to make the German set course for home.
Matz in U-70 had submerged. He now came under coordinated attacks from two corvettes. Wallowing and unstable he went to 650 feet: far deeper than the submarine was designed to endure. The damage sustained from the Dutchman which rammed him, together with the depth-charging, started leaks and made the U-boat impossible to control. Despite the crew’s efforts the U-70 surfaced and was fired upon. The crew surrendered as the stricken boat reared, bow in the air, and slid under, taking 20 of the crew with it.
Even the stubborn Kretschmer dived deep and sat ‘in the cellar’. He watched the rivets pop and the lights flicker as the explosions came and went. Carefully he withdrew, with half his torpedoes still unused. The convoy sailed on, having lost two ships, and had two damaged.
Prien followed the convoy and tried again at dusk, his approach covered in fitful rainstorms. But in a clear patch he was spotted by a lookout on HMS Wolverine and his crash-dive failed to save him from the depth charges that damaged his propeller shafts. Instead of turning for home, he surfaced after dark for another attack, perhaps not realizing how clearly the damaged propellers could be heard on the asdic. This time Wolverine, which had tenaciously waited in the vicinity, made no mistake. As the U-boat crash-dived, an accurately placed depth charge caused the submarine to explode under water, making a strange and awful orange glow. ‘The hero of Scapa Flow has made his last patrol,’ said the obituary notice personally dictated by Admiral Dönitz when, after 76 days had passed, they finally told the German public of their hero’s death. Even then stories about him having survived circulated for months afterwards.
A few days later on 15 March 1941, south of Iceland, Fritz-Julius Lemp, now promoted to Korvettenkapitän, signalled the approach of a convoy. It was an attractive target but the escort was formidable. The escort commander was Captain Macintyre RN, who was to become the war’s most successful U-boat hunter. He was in an old First World War destroyer, HMS Walker. There were four other old destroyers with him, and two corvettes. The homeward convoy HX 112 consisted of almost 50 ships, in ten columns half a mile apart. They were heavily laden tankers and freighters, and even in this unusually calm sea they could make no more than 10 knots (11.5 mph).
Lemp’s sighting signal was intercepted by direction-finding stations in Britain. Such plots could only be approximate, but Captain Macintyre was warned that U-boats were probably converging on HX 112. Without waiting for other U-boats, Lemp’s U-110 surfaced and used darkness to infiltrate the convoy. Two torpedoes from his bow tubes missed, but one from his stern hit Erodona, a tanker carrying petrol, and the sea around it became a lake of flames.
The next day other U-boats arrived. The uncertainties of U-boat operations are illustrated by the way in which U-74 never found the rendezvous and U-37, having surfaced in fog, was run down by a tanker and had to return to base for repairs. But Schepke (U-100) and Kretschmer (U-99) provided enough trouble for the resourceful Captain Macintyre. Having spotted Schepke’s boat, the escorts started a systematic search which kept it submerged and allowed the convoy to steam away. At this stage of the war the escorts had not discovered that U-boats impudently infiltrated the convoys to fire at point-blank range. The search for the attackers always took place outside the convoy area. So the chase after Schepke was Kretschmer’s opportunity to penetrate the columns of the virtually unprotected convoy, and at 2200 hours there was a loud boom which marked the beginning of an hour during which Kretschmer hit six ships. Five of