by Dudley Pope
No messages from Johnny Gower, so there were no ideas from the escorts. And, he reflected bitterly, no messages from him to Johnny Gower either. Sailing in the Marynal was a crazy idea, and one he would never have had except that he was getting desperate. A contented mind might be a continual feast, but a desperate mind is a fertile ground for crazy ideas. Now he was stuck for weeks in this damned convoy. If only one of the frigates – better still one of the corvettes, because that would not weaken the escort too much – developed some defect that required her to go into Londonderry, or anyway return to the British Isles – then he could cadge a lift back and report to Uncle.
It was hard to guess what Uncle’s reaction would be. Perhaps patient and accepting that the only way to be sure the Swedes were not up to some nonsense was to sail in a convoy and watch them. He might be irritated, having had second thoughts himself soon after Yorke left London. He might be under great pressure from Downing Street, in which case Yorke would receive a monumental bottle, and Uncle was just the kind of man – quick tongue, fluent command of the language – to be good at handing out bottles to errant lieutenants.
Well, standing up here on the bridge looking astern, like a seagoing Wellington surveying the lie of the land at Waterloo (well, perhaps not a battle that later rated a railway station; maybe one of his defeats. Or just staring down from the heights of Torres Vedras was more like it) was achieving nothing. He had some old copies of Horizon to read – it was always amusing to read that bunch of Spanish War poets and writers patting each other on the back and saying how wonderful they were, even if several had fled to the safety of America, shouting across the Atlantic how freedom must be defended at any price. He went down to his cabin, knowing they would irritate him so much he would end up reading a pre-war Blackwood’s again – there were several left in the bookcase.
He had been reading for less than half an hour when Cadet Reynolds came down to report that the Penta had just received permission from the commodore to complete her repairs. Yorke put on warm clothing and went up to the bridge, where Captain Hobson was standing inside the wheelhouse, examining the Swedish ship with binoculars.
‘She’s swinging out now and reducing speed,’ he said. ‘It’s what he told the Commodore last night.’
‘Doesn’t seem to be smoking much,’ Yorke commented.
‘Aye, but I had a word with our chief engineer. He says the smoke yesterday could have been just the normal sooting up, and what the Swede actually stopped for might have been something quite different.’
Yorke went back to his cabin and tried to forget about the Penta until, an hour before nightfall, he watched her rejoining the convoy. There was the same high speed approach from over the horizon, the same slowing down two or three miles astern, and the same leisurely return to her position in the convoy.
He commented to Captain Hobson: ‘That’s just how we’d do it. And he hasn’t called up the commodore so I suppose all his repairs are completed.’
Chapter Fifteen
Wind force six to seven from the south-east, ten-tenths cloud, attack began at 1955, the first three ships in the sixth column torpedoed. The second of them had been abreast the Penta, the third abeam of the Marynal.
As an angry and baffled Yorke sat in his cabin and wrote the details of the second night’s attack in his notebook he was still looking for patterns. In the previous night’s attack when two ships had been torpedoed in column four and one in column five, the two ships had obviously been hit by the U-boat’s bow tubes and the single by the stern tube. Assuming the U-boat was firing single torpedoes, the first night’s attack had cost him three fish.
Tonight’s attack had been much simpler: the German had not used his stern tube: he had probably stayed in the same place between columns five and six and fired single torpedoes as the first, then the second and then the third ship in the column passed across his sights. Three ships were hit within a hundred yard square. The second had probably been hit before she had time to swing clear of the first; the third was hit because the U-boat turned slightly. That much was clear from the timing of the explosions and the positions – the third one had been abreast of the Marynal when the torpedo hit.
Three torpedoes probably used up tonight, three last night, six in all. Eight more left. Or perhaps the U-boat had missed one ship. That would make seven, but no one was likely to see a miss because the Germans were using electric torpedoes.
All of which meant that this insider still had seven or eight torpedoes. By now he was probably many miles away from the convoy, surfaced to charge batteries. He might even be sending the brief signal to Kernevel, telling Doenitz of his success.
The signal need only be brief, giving the grid square of the convoy and its course and speed, and that the U-boat had sunk six ships (and the Oberleutnant would probably guess at their total tonnage). Or he might wait a day or two until he could add that he was returning to base. In this weather, with a following sea, he could probably make fifteen knots on the surface – a cold, wet and wild pitch-and-roll ride but no one would mind because they were heading for home after a successful operation. They would cover a good three hundred and fifty miles a day until they came into the range of Coastal Command; then they would have to be wary, probably moving submerged in daylight. But in three days they would be in somewhere like Brest or Lorient, St Nazaire or La Pallice, perhaps Bordeaux. No action damage to be repaired and cockahoop at having sunk at least six enemy ships without having one depth charge dropped by the convoy escort…
Yorke found himself writing:
1 Has the Ted skipper eight fish left?
2 Will he attack tonight and still firing singly?
3 Why would he risk another attack, having sunk six ships? Answer. He should be confident in view of lack of opposition.
4 So it is probable that if he has fish left, he’ll attack again tonight.
5 If the Penta drops astern again today and there is an attack tonight will that be significant? Not really, on present evidence.
He looked again at the last few words ‘…not really, on present evidence.’ It was as simple as that: there was nothing that linked the Penta to the insider, and that was that.
The whole thing made as little sense out here in the North Atlantic as it did in the ASIU’s underground room at the Citadel. The question then was the same as it was now: how does the bloody insider get inside?
The escorts made the convoy into a box open at the top (but U-boats couldn’t fly) and the bottom. So the only way for a U-boat to get inside the convoy was through the bottom – by approaching submerged. That much was obvious, even to an imbecile.
How many times had he gone over all this before leaving London? The U-boat could get ahead of the convoy, dive, hide beneath a cold layer of water where the escorts’ Asdics would not pick it up, and then come up to periscope depth after the leading escorts had passed and the convoy was steaming above, like someone popping his head out of a manhole to say ‘Boo’ at the passing ladies. So far, so good, for the insider. All very practical, and nothing even an escort commander as smart as Johnny Gower could do about it, providing the Ted captain found the cold layer.
Now for the but. It was a large-sized ‘but’ and one on which the waiting-ahead-of-the-convoy theory sank in a flurry of foam. It was a fact of German U-boat life (and confirmed by trials made in the U-boat recently captured intact by the Royal Navy) that although it could make nineteen knots on the surface using its diesel engines, once it dived and had to use its two electric motors, its speed and range were limited by its batteries. It could make nine knots for an hour before its batteries were flattened, or it could stay under for three days (in an emergency) making one or two knots. In other words the batteries contained only so many ampere hours, and the captain could use them up at a rush by going fast for a short time, or eke them out by going slowly. Like an alcoholic with a bottle of
whisky – empty it in an hour, or make it last three days.
What the U-boat could not do was make six knots submerged for days on end… Unless he was making only a knot or two, he had to surface every twenty-four hours and run his two big diesels so that the generators recharged the batteries.
How is he escaping from the convoy box after a night’s attack so that, out of sight of the escorts, he can run on the surface and charge his batteries? We have answered that – he just dives deep and lets the convoy pass over him. And he stays down until he knows he is out of sight of the convoy, then he surfaces, starts up the diesels, gives the lads a breath of fresh air, and lets in the clutches on those big generators, so that the batteries start getting a charge for the next night’s operation.
All well and good: Yorke had gone over the sequence enough times in the Citadel, with Jemmy and the Croupier joining in. There was no set time required for charging the batteries – obviously it depended how much current the electric motors had used the previous night. Perhaps five hours; maybe ten. Jemmy had been emphatic that three days submerged would leave the crew in a poor state because of lack of oxygen and humidity, and probably flatten the batteries. Such a long dive was usually the last resort, when a hunted U-boat was trying to sneak away from an attacker who had the time to stay around and pursue the search.
How did the bastard get back into the box?
That was the question that stumped them in the ASIU headquarters at the Citadel; and now he had seen a convoy attacked by an insider on successive nights, he still had no idea. Captain Hobson had decided that the U-boat simply got ahead of the convoy again during the day, submerged, and came up to periscope depth at the right moment among the columns.
Hobson had been quite sure of that until Yorke scribbled a few figures on a pad. The convoy attack had stopped by 2100 on both nights, so they could assume the U-boat dived deep at that time and an hour later was somewhere astern running on the surface, already charging batteries. By daylight next day, about 0700, he had nine hours’ charge in his batteries.
At daylight he could – if he wanted to take the risk – still see the convoy, but if he was running on the surface and able to see the convoy, then one of the escorts was just as likely to spot him, or pick him up on radar, even though the sets the frigates had at the moment were crude.
The important thing was that from 0700 until the German attacked that night was at least twelve hours. During that time the convoy had made about seventy miles, and zigzagged at least once, probably twice, and perhaps thrice. It was quite impossible (even if he had the zigzag diagrams in front of him) for the U-boat to race ahead of the convoy and submerge at a point up to fifty miles away where he knew the convoy would not just pass, but pass immediately overhead. From one side of the convoy to the other was only 1200 yards. The first two attacks had been made on the fourth and fifth columns. That meant not only was the U-boat picking a spot across which a convoy 1200 yards wide would pass, but two columns only 200 yards apart.
The Ted could tear around for half an hour at nine knots submerged so he could change his position by, say, five miles (leaving himself some juice in the batteries to manoeuvre for the various attacks), but if he moved on the surface or submerged then Johnny’s escorts would find him: the two frigates were crisscrossing ahead of the convoy all the time, night and day. Yesterday Johnny had put his third corvette right in front, only a few hundred yards ahead of the commodore, and no Asdic had produced an echo, that much was obvious. The U-boat, Yorke had demonstrated to Hobson, was not entering the convoy box that way.
Finally, almost cross-eyed with fatigue, Yorke shut his notebook. It must be black magic, an old recipe kept in an ancient sock by a charcoal burner’s great-grandmother in the depths of the Hartz mountains, levitation, knowing which form to fill in or which bureaucrat to bribe…what other explanations were there? He undressed and slid into his bed. If the weather worsened he would envy those with bunks – the only way he could stop himself sliding out of this well-sprung bed as the ship rolled would be by lying spread-eagled on his back.
Years of watchkeeping meant Yorke could waken within a few minutes of the time he set himself, and he woke just before a cadet knocked on his door, telling him it was nearly noon. After a brisk shower and a shave – during which time he could see through the porthole that the weather had improved slightly – he dressed and went up to the bridge. The Penta was missing.
Captain Hobson said he had called the commodore about eleven o’clock, and from the commodore’s reply it seemed the Swede was claiming engine trouble again. He had, just like the previous two days, pulled out of the column, slowed down and let the convoy draw ahead. Yorke could see for himself that the Penta was now out of sight astern, and the convoy had altered course at eleven thirty according to the zigzag diagram.
Grey ships steaming along on a grey sea under a grey sky; a long grey swell rolling in from the west. There had been no hint of the sun at noon, so there had been no sights; the barometer was staying the same. Yorke walked into the chartroom to look at the chart. Hobson had put a pencilled cross, with the time and date, showing the noon position by dead reckoning, and the convoy’s zigzag progress across the chart was so slight he had to use a sharp pencil. Six knots – Columbus’ little ships must have crossed to the New World at about that speed when running before the Trade winds. Six knots. A man walking briskly made five. The convoy from Liverpool to Freetown was going the whole way at slightly more than the speed of a man walking to church on a Sunday morning with a nip in the air. That was the speed at which most convoys crossed the Atlantic, simply because six knots was the speed that most small merchant ships could guarantee to maintain…
Suddenly in his imagination he saw astern, out of sight just below the curvature of the earth, the Penta and the U-boat. He saw them stopped close to each other, the U-boat rolling and pitching uneasily in the swell, a grey cylinder, tiger-striped with rust, the waves slopping and squirting through the gratings of the deck plating. Did the Swede lower a boat and take across fresh bread and other comforts? Pass across special hose and pump over diesel fuel?
He found himself sketching the two vessels lying close together, using the pad left for the navigator’s rough calculations. Neither merchant ship nor submarine would dare get too close to each other because even a slight collision could sink the U-boat. But if the Swede passed a cable and took the U-boat in tow at slow speed, a hose could be passed without any trouble and without any risk of collision.
In fact the Penta could tow the U-boat back to within sight of the convoy.
Or, more likely, the Swede could chase the convoy at full speed, say fifteen knots, with the U-boat on the surface astern of her, charging batteries at the same time… From the high vantage point of the Penta’s monkey island they could keep a sharp lookout for the British escorts, knowing the Penta’s bulk would hide the U-boat from radar, and once they were close, within three or four miles, they could slow down – as they had done before – and the U-boat could dive at the last moment.
The U-boat would still be outside the convoy, outside the box with three corvettes and two frigates circling round it, Asdics pinging, the sound waves radiating out with sensitive receivers waiting to catch even the hint of an echo from something solid. And the hydrophones, like old men’s ear- trumpets, listening for unusual noises, the sound of a U-boat’s electric motors and the swish of the propellers. But the hydrophones were useless when very close to a convoy, deafened by the pounding of the pistons of the merchant ships, whether they were steam or diesel… The effect would be the same as a quavery old lady trying to make herself heard to someone using an eartrumpet as a brass band marched by thumping out a lively ‘Colonel Bogey’.
Captain Hobson was leaning over the chart table beside him and Yorke suddenly realized the Yorkshireman was staring at him open-mouthed. ‘No one would expect what old lady to compete in what?’ a startle
d Hobson asked, and Yorke realized he had spoken his thoughts aloud.
‘Hydrophones,’ he said lamely. ‘They’re like an old man’s eartrumpet. Sound carries fantastically under water. Very effective, a hydrophone, providing the operator is well trained. Some chaps get a sort of sixth sense. Of course, you can’t chase something at high speed, or your own noise deafens the hydrophone operator.’
‘What about the old lady?’ Hobson asked.
Yorke was embarrassed at trying to explain his thoughts to this down-to-earth man.
‘I was thinking that an old lady wouldn’t try and compete with a brass band by shouting into an eartrumpet…’
‘I should hope not,’ Hobson said. ‘Mind you, eartrumpets have gone out of fashion now, you know. Haven’t seen one for a long time. Nor a brass band, come to think of it. Still plenty of old ladies around – competing old ladies, too.’
‘That bloody Swede,’ Yorke said. ‘I was thinking of her meeting the U-boat back there, over the horizon…’
‘Aye, I’m glad you’ve got round to thinking about that,’ Hobson said with an about-time-too note in his voice. ‘I’ve been thinking of them passing over bottles of schnapps and tins of Stockholm tar. And saucy postcards – you’d be surprised what those Scandinavians get up to. I see you’ve been sketching it,’ he said, pointing at the pad.
‘And fuel, too,’ Yorke said, tapping the chart table with his pencil.
‘Aye, that’d be a help; but I still don’t follow what you meant about the old lady and the eartrumpet.’