by Dudley Pope
Yorke picked up his diagram and walked over to Jemmy who glanced up and combined a twitch with a grin when he saw who was standing beside him. ‘Solved the riddle, Ned?’
‘No, I just want to peer into the devious mind of a submariner. Look, eight ships sunk by the same U-boat. Five are each hit by two torpedoes, but three others get singles.’
‘Ten fish expended on five, plus three, makes thirteen fired. Any misses seen?’
‘No, not one. No phosphorescence.’
‘Thirteen…and a U-boat carries fourteen, so either he missed with one fish that no one sighted, or he kept it in reserve for the trip home. Or one was defective. What do you conclude from all that?’
Ned shrugged his shoulders. ‘That convoy was like all the rest of them: when the U-boat joined in he had a full outfit of torpedoes. Which means, I suppose–’ it hit him like an almost physical blow, ‘–yes, that it’s definitely not chance that puts a U-boat into the middle of a convoy. Every U-boat up to now has had a full outfit of torpedoes. So old Doenitz is planning it in Lorient. Kernevel, rather – or wherever he has his headquarters.’
Jemmy’s eyes narrowed and he seemed to be staring at a far horizon. ‘Ned, keep on talking…’
‘Well, I’m not too sure of that, come to think of it. Most of these convoys are homeward bound, which means they’re loaded down and also sailing from places thousands of miles from Lorient. Halifax, Nova Scotia, New York, Freetown and so on. Each convoy I’ve checked so far was attacked by a U-boat which fired at least a dozen torpedoes. That makes me wonder whether each of these U-boats sighted a convoy by accident, as it were, and somehow got into the middle and attacked until all its torpedoes were used up, or whether the U-boat was there with a full outfit of torpedoes to attack a particular convoy: whether it was sent out from Lorient full of fuel and fish with orders to wait for convoy number so and so in a certain position.’
‘You mean, the Teds know when our convoys sail. Or at least the ones that are attacked. Is that likely, Ned?’
Yorke shrugged his shoulders again. ‘I’m only thinking aloud. But isn’t it too much of a coincidence that the first five “insider” convoys I check were all attacked by U-boats with full outfits of torpedoes? If you command a U-boat what would you reckon on your chances of sighting a particular type of convoy before you’d fired any torpedoes?’
‘Pretty good,’ Jemmy said. ‘After all, most attacks are on convoys, not single ships. But the chances of staying with that convoy are not so good, so I might then find a second convoy with only half my torpedoes left. But Ned, keep thinking on these lines…this last convoy: the chances of a U-boat with a full outfit of fish picking it up just after leaving Freetown does seem a hell of a coincidence. There are so many single ships running along the West African coast – between Freetown, Takoradi, Accra, Lagos, Calabar, Port Harcourt – that…well, it’s surprising, to say the least.’
‘And the ships hit with two torpedoes, Jemmy?’
‘That’s either definite orders from U-boat Headquarters or this particular Ted captain thinks a bird in the hand is worth two in the bush.’
‘I don’t follow you.’
‘Well, you have fourteen torpedoes. In theory you should be able to hit fourteen merchant ships. In fact we know from experience and radio intercepts that usually a U-boat is lucky if it sinks four ships on each trip, even when part of a pack. That probably means ten fish missed. Most captains dread running out of fish – they’re sure the enormous target of a lifetime will loom up the moment they’ve used the last one. So even though a captain knows he should fire two fish at every target – which could give him seven ships sunk – he usually tries to get away with firing one. So the Ted attacking your convoy was either acting under orders or he was a realist, an experienced skipper who knew it was better to be certain of one ship for every two fish rather than gamble on one for one. Sensible chap.’
‘What would you have done?’
‘What I always did, Ned my lad: if it is worth the risk of getting into a firing position, which means farting around at periscope depth, dodging escorts, it’s worth firing two fish to make certain of one sinking – after all, you’re risking your whole boat and crew. Mind you, occasionally you find a target where all the conditions are perfect and one fish is enough: your Ted found three like that in this convoy, but he wouldn’t gamble on the other five.’
Yorke took back the diagram and said ruefully: ‘All we’ve learned from that lot is that a U-boat usually has a barrowload of fish when it meets a convoy.’
‘That a U-boat going to attack from inside has a barrowload.’ Jemmy corrected.
‘I’m beginning to dislike submarines and submariners,’ Yorke grumbled. ‘Why don’t you tell me all about ’em? Ted ones, I mean.’
‘Right,’ said Jemmy, ‘grab a notebook and make some notes while I deliver my “Meet the Ted U-boat” lecture. I start off with this gesture–’ he gave a thumbs down sign ‘–which means: “We who are about to be torpedoed say ta-ta to the tarts in Trafalgar Square.”
‘Now, at the moment we reckon Doenitz can keep between 200 and 250 boats at sea at all times. His headquarters are at Kernevel, which is a small town near Lorient. His Atlantic boats can refuel at six places – Brest, St Nazaire, Lorient and Bordeaux, La Pallice and La Rochelle.
‘Now for the boats themselves. Various types, so I’ll describe the latest we know about. Commanded by an Oberleutnant (occasionally a Kapitänleutnant) with a first lieutenant (responsible for torpedoes and gunnery), a second officer (radio and ciphers) and an ensign (similar to a sub-lieutenant) who is the navigator. The engineer is a lieutenant.
‘There are signs that Doenitz is getting very short of really experienced captains – we reckon we’ve sunk about a hundred boats in the last twelve months. We captured Kretschmer, and two of the other aces, Schepke and Gunther Prien (the chap who sank the Royal Oak), have been killed. Still, Doenitz has the pick of the German Navy’s men, even if he has to promote ’em fast to keep up with new building and losses.
‘A typical boat – well, 770 tons, 75 metres long, six metres diameter. Twin diesels, of course, which give it nineteen knots on the surface and charging batteries at the same time. Generally they have to recharge every twenty-four hours. Submerged speeds? Well, according to the information we have, they can make a maximum of nine knots submerged for an hour; after that their batteries are almost flat. Or they can chug along submerged at one or two knots for three days – by which time the air is nearly solid.
‘Depths? Again, it varies with the type of boat, but the latest we know of can dive safely to 120 metres, which you can call sixty fathoms, or more than 400 feet. The newest boats can probably double that by now.’
Yorke sensed that Jemmy envied and admired the German boats. ‘What armament?’
‘Fourteen fish, with electric drive, so there’s no trail of compressed air bubbles to give ’em away. You’ll only spot tracks when they go through patches of phosphorescence. Four tubes forward and one aft. They can fire four in quick time. They’re discharged by compressed air, so on the surface in daylight you might spot a few bubbles. Enough to say “Boo” to. So much for fish. In the bang department they have an 88 mm gun – that’s the flat trajectory job that’s bashing up our tanks in the Western Desert – and a couple of 20 mm cannon for anti-aircraft stuff.’
Yorke finished scribbling notes and then said: ‘I know British and German subs are different, but use your imagination and describe what it’d be like in a Ted submarine while she’s making an attack. What the skipper is thinking, what happens if she’s depth-charged. I want to try to get into the skin of a U-boat commander. Maybe that’ll help me working out how he thinks.’
‘I can do that,’ Jemmy said, ‘and better than most because I’ve been in a U-boat. It’s secret that we’ve ever captured one, so keep your mouth shut, but i
t’s one of the reasons why I’m on this zigzag diagram lark: I’m supposed to be a specialist in Ted submarine tactics.
‘Okay, then. You could get the next bit from the Croupier, but I know it and he’s busy, so I’ll give it to you. You’ve seen the big gridded chart he’s got. The Teds don’t use ordinary ocean charts with latitude and longitude – for U-boats, anyway. The charts are gridded, letters of the alphabet in pairs one way and numbers the other. This system probably changes a lot. Anyway, our U-boat surfaces for its night’s battery charging and picks up a radio transmission from U-boat Headquarters at Lorient. The message might be something like: Emergency, All U-Boats With Torpedoes Proceed Full Speed To Grid Square AB 64 Where Convoy Expected Pass Six Knots On Course ESE.
‘That signal would come over in cipher and the second officer would be called to crank it through the cipher machine. If we had torpedoes and if we could reach AB 64 within a reasonable time, we’d go up to full speed on the surface. If we picked up the signal soon after darkness on a winter’s evening, don’t forget we can be more than 200 miles away by dawn.
‘Once we get to AB 64 we search and if we sight the convoy we might try a daylight attack if we are in the Black Pit, outside the range of Allied planes. Most probably we’d shadow at extreme range until before nightfall, and making sure we’re in good attacking position by then.
‘We’d shut down the diesels and go on to the electric motors, diving and rigging the boat for silent running. Four fish loaded in the forward tubes, one in the after tube. Motors turning at something between sixty and eighty revolutions. We’d have plotted the convoy’s course and speed by now and I’d have had a guess whether they’re on the leg of a zigzag or not. I’d be watching the sea water temperature gauges, too, looking for cold water layers. The Teds were lucky. When they captured French warships at the fall of France they captured the Royal Navy’s biggest secret – one we should never have shared with the Frogs. They found our Asdic… The magic ping that bounces off the Ted boats and comes back up and registers as a bearing. They also found what we’d long known and kept secret – that the ping won’t go through a layer of cold water. All this you know well enough, but I’m like a gramophone record, I have to start at the beginning and go on until the end.
‘Anyway, I’d be watching the gauge to see if there’s a convenient cold water layer around in case I want to hide underneath it, like a bomber dodging under a cloud to hide from a fighter above, with the difference that the fighter can’t come down through the cloud!
‘I’d pop up to periscope depth for a few moments every now and again, just to check the convoy hasn’t zigged and to try to plot where the escorts are. One might even come towards me and I’d dive deep and shut off everything and no man would move. We’d hear the ping of the Asdic impulses, high-pitched, like a wasp sending dots in Morse. We’d all be breathing shallowly – pure nerves. Then maybe the escort would think she was getting an echo on the Asdic. She might stop, so her own turbines didn’t interfere with her hydrophones. If she stops reasonably near we’ll be hearing the ping-ping-ping of the bloody Asdic, and the whine of her auxiliary motors and pumps – fantastic how sound travels through water, and anyway our ears are working overtime.
‘We’d hear her starting her turbines and there’d be a slowish swishing noise as her propellers started turning. Then maybe we’d hear a single splash, a double and then a single… Which would mean, Ned my old chum, that the escort has dropped a diamond pattern of four depth charges.
‘If they explode too near us the boat will groan as though someone is twisting the hull like a dry cigar. There’ll be some noisy banging overhead as the pressure waves make deck plates jump. Inevitably the glass of some dials will break – hardly surprising; the jerk you feel from the explosions will loosen your teeth, too – and the inevitable leaks will be reported: propeller shaft packing leaking, valve seats and gaskets letting water trickle in… The main thing is that if there isn’t too much water we don’t pump it because pumps mean noise and, like the mouse, we know the cat is up there waiting and listening.
‘That’s about all there is to an attack on the boat. One gets to know the noises well enough – the pounding of the cylinders of a triple-expansion steam engine, the fast drumming of diesels, the singing of steam turbines. They make noise; so do you. The chap with the best ears wins! But the skipper’s morale – if he’s anything like me – is likely to be more affected if he’s been through a long spell of bad weather – North Atlantic winter sort of stuff, when every time the hatch is opened half a ton of beastly cold water crashes down and drains into the bilge, every man comes off watch soaking wet and frozen, trying to dry his clothes, and the humidity down below gets so high it is nearly precipitating into rain in the wardroom. There’s condensation streaming down the bulkheads, the damned charts get soggy like blotting paper and when you move the parallel rules across them, the rollers stick and the edges take bites out of the paper, and if they’re the sliding sort they won’t slide. Everyone’s snappy, everybody seems to be farting, and the atmosphere gets vile. The weather’s far too bad to keep the hatch wide open…it’s the sort of time when you pray for the ammeters and voltmeters to hurry up and show the batteries are charged so you can dive to get out of the rolling and pitching – but diving won’t reduce the humidity…’
Yorke smiled as he said: ‘I’m sorry when it happens to you, Jemmy, but I’m glad it’s hell down there for those Teds! Anyway, I get the picture. Let’s say we’ve attacked and sunk some ships. What do we do now?’
‘Well, assuming we’ve no more fish, we surface at night and transmit a ciphered report to Lorient – something brief like Convoy Grid Square CD 32 Course 090 Six Knots Sunk Three Ships 18000 Tons All Torpodoes Expended Returning Base. That would go off to Lorient, Doenitz would rub his hands, and any other U-boats in the area who didn’t pick up the original report on the convoy position would turn up the wick and hurry to grid square CD 32.’
‘This would be in U-boat cipher?’ Ned asked.
‘Yes. Pretty simple stuff because of course as far as the Germans are concerned the Allies know how many ships they’ve lost in that convoy, they know where it is, and they know U-boats are round the convoy so using direction- finders on the transmission doesn’t help much. The route our boat takes back to Lorient can vary by 500 miles north or south of a rhumb line.’
Jemmy waited until Ned had finished writing. ‘Any questions? I don’t seem to have told you much. You’ve chased enough U-boats in that destroyer of yours. In fact as far as I am concerned, destroyers are the enemy, no matter whose they are!’
Ned thanked him and went back to his desk, picking up the next docket. The sixth convoy had been attacked five weeks after the fifth, thirty-seven ships bound from Halifax to the Clyde. Five sunk and one more damaged but taken in tow, although finally sunk by the escorts. Five had each been hit with two torpedoes, while the sixth had been hit by one but had seen another miss ahead. Twelve torpedoes definitely fired for a score of six merchant ships, probably two other misses.
He looked at the list of ships and their positions. Fourteen American, sixteen British, three Norwegian, one Dutch, one French, one Swedish and one Greek. All those sunk had been in the centre columns. Weather reasonably good, the attack lasting only four days. No further attacks after the sixth ship was hit, and no pack attacked, although the Submarine Tracking Room report in the docket said there had been a pack passing to the south which subsequently attacked another convoy. He drew the convoy diagram more out of habit than anything else and glanced up to find Joan standing at the side of his desk. ‘Uncle would like to see you,’ she said. ‘Nothing alarming – he just wants to hear how the detective work is going.’
Ned grunted and Joan, glancing at her watch, misunderstood and said: ‘Are you meeting her for lunch? It won’t take more than fifteen minutes – unless you talk a lot.’
‘Thanks for the kind
thought, but we said goodbye this morning.’
‘Did you have a nice weekend?’
‘Yes,’ Ned said and without thinking added: ‘You look as if you did, too.’
Joan smiled and said, ‘Yes, it does wonders for the complexion.’
And, Ned thought to himself, realizing that although Jemmy still had a king among twitches, he seemed much more relaxed in the last few days, it must be good for overworked submariners, too.
Uncle was relaxed like a tiger in the shade after a good meal: comfortable, tractable and cheerful, but ready to spring at a moment’s warning.
‘How is it going, Yorke? Anything interesting turned up?’
‘No, sir. They’re all alike. The ships are sunk in the middle of the convoy. From the fourth convoy onwards it seems Doenitz ordered them to fire two torpedoes at every target.’ He thought for a moment. Did Uncle want to chat about it all, to throw ideas back and forth, or was he interested only in specifics? Well, there was no harm in mentioning it. ‘I’ve been totalling up the number of torpedoes fired against each convoy, and it seems that every U-boat had a full outfit of fourteen torpedoes on board when he began his attack, or certainly never less than a dozen.’
‘Have you mentioned it to Jemmy?’
‘Yes, sir: he thinks it is a hell of a coincidence, particularly in cases where the attacks began a day or two out of Halifax, or Freetown. And a hell of a long way to go with a full barrow of fish.’
Uncle picked up a pencil and balanced it across the index finger of his left hand. ‘A hell of a long way unless your orders were to attack that particular convoy and no other…’
‘That’s what Jemmy and I thought. But being ordered to attack a particular convoy implies the Ted knew it was due to sail. Which means spies – or else they’ve broken some of our ciphers.’
