JUNE-SEPTEMBER 1944
JUNE 1944
THE NORMANDY INVASION
432. Prospects of the schnorkel boats
For some weeks prior to the beginning of June, the Biscay-based Type VIIC U-boats, on becoming ready for sea, had carried out deep-diving and trimming trials and then returned to base, remaining at six hours’ notice. It had been our intention to equip most of these boats with schnorkel during May; but production delays occasioned by the Allied bombing offensive in Germany prevented this from being done. Moreover, the progressive disruption of traffic in France led to loss of much of the equipment which was despatched. In the event, only eight boats were equipped that month, of which five were formed into group Dragoner and sailed, between 17th and 25th May, for the western part of the Channel to operate, with the support of the shore radar service, against the enemy cruiser and destroyer formations which made occasional excursions into that area. Although valuable experience was gained during the operation, both in the use of the schnorkel and in the tactics to be adopted in an area heavily patrolled by aircraft, results were disappointing in that no contacts resulted from a steady stream of information passed to the U-boats. At the same time we were dismayed to discover from radio intelligence reports that the enemy was very soon aware of the location of the boats through detection of the schnorkel by airborne radar.
As group Dragoner’s operation had shown that schnorkel-fitted boats were able to remain in an area dominated by enemy aircraft, it was possible to plan for their future employment in the Channel against the enemy’s invasion forces. Indeed, consideration was given to moving them at once to bases on the French north coast; but this idea was rejected, since, with no bunkers available at Cherbourg, Le Havre or Boulogne, the U-boats would have fallen easy victim to air attack, even before the invasion occurred. Operational control of Channel U-boats was, however, transferred to the SO U-boats West since he was thoroughly conversant with the minefields in that area and also for fear of a breakdown of communications between Germany and western France at the beginning of the invasion.
433. Initial operations against the Normandy landings
At 0001 on 6th June, U-boat dispositions in Home Waters were:
(a) Group Mitte, comprising 22 non-schnorkel boats, lying at six hours’ notice at Bergen, Stavanger and Kristiansand.
(b) Ten non-schnorkel and seven schnorkel-fitted boats en route from Norway to the Atlantic, some of them already 300 to 500 miles south of Iceland. Actually, five of these boats had already been destroyed and one damaged, but we were unaware of this.
(c) Three Type IX boats on weather reporting duty in 30 degrees West.
(d) Group Landwirt, comprising 37 boats all told. Of these, eight schnorkel-fitted and nine non-schnorkel were at Brest; while the remaining 19, of which only one was fitted with schnorkel, were distributed between St Nazaire, Lorient and La Pallice. All were at six hours’ notice.
First information of the landings reached U-boat headquarters at 0305 on 6th June, and groups Mitte and Landwirt were brought to immediate notice; the five schnorkel boats which were already in the Atlantic were ordered to make for Western France at high speed, while those still to the west of Norway were halted and told to remain in their present positions until further orders.
In this hour of crisis the role of the U-boats was decisive to the outcome of the war and every available boat had to be flung into the battle, regardless of cost. Clearly, their primary task was to attack the invasion fleet off the Normandy coast. But this area was only accessible to schnorkel boats and even they would have great difficulty in reaching it, since the enemy would surely devote a large proportion of his uncommitted A/S forces to the protection of his western flank. However, should the eight Landwirt schnorkel boats succeed in forcing their way into the central English Channel, their prospects of success against the great weight of shipping to be found there might be good. The chances of their effecting a breakthrough would certainly be enhanced if further boats were transiting the area at the same time; so, with the additional knowledge that a number of enemy supply convoys were coming from the direction of the Irish Sea, Dönitz was compelled, against his better judgement, also to send the nine Brest-based non-schnorkel boats into the danger area on the first day in order to attack traffic passing through the western Channel on its way to Seine Bay. For the rest, since the enemy had complete air superiority and we were thus unable to discover whether or not he intended to land elsewhere, the remaining non-schnorkel boats of group Landwirt were sent to cover the approaches to the Biscay coast, while those boats which had been halted west of Norway were assigned specific patrol areas and group Mitte remained in harbour at short notice.
434. First U-boats in the Channel
Despite a shortage of local escort vessels and frequent interruption of Headquarters communications, SO U-boats West managed to sail 35 of the 36 boats of group Landwirt on the first day of the landings. The eight schnorkel boats were sent to the area north of Cherbourg, where they were expected to arrive in five to six days, and the nine non-schnorkel boats from Brest to the area between Lizard Head and Hartland Point. They were ordered to proceed at high speed on the surface and consequently had to fight their way through against enemy air opposition. But there was no alternative to this, since it was essential to bring our forces to bear while the invasion was still young and the enemy therefore at his weakest; besides which the boats had to be out of Brest and well away from the coast that night, in order to get out of range of the enemy A/S forces patrolling just off the harbour. As was to be expected, this mass exodus of U-boats evoked the strongest enemy air activity hitherto encountered, nine boats reporting having been attacked, while double that number of attacks and sightings were reported by the enemy aircraft engaged. Subsequently it appeared that more than 50 air attacks occurred on that first night, while four large aircraft were shot down. The drama of some of these incidents is illustrated by the log of U.415:
“… 7th June 1944, 0140. Sea 1 to 2, swell, moonlight, good visibility. Dropped escort off Brest. Course 270 degrees, full speed (15 knots).
0145. Next astern attacked by aircraft. I open fire with her. Aircraft shot down by U.256. Radar audible on all bearings, strength 3 to 4.
0220. Radar no longer audible to starboard, so assume aircraft on run in. Sunderland approaches from green 40. I open fire. Four bombs fall just ahead and detonate under the boat. Liberator attacks simultaneously from the starboard beam, firing her guns which hit my bridge. She drops no bombs. The Sunderland’s bombs have brought my diesels to a standstill. The boat rises high in the water and settles by the stern, so that water enters the conning-tower hatch. Order ‘Clear lower deck; clear away rubber dinghy’. Radio out of action so cannot report. Manned emergency radio transmitter on bridge. Rubber dinghy and life-buoys are being cleared away. Boat remains afloat, so order all ammunition on to the bridge. Rudder jammed to starboard.
1228. Sunderland renews attack from starboard, firing her guns and dropping bombs from low altitude. Bombs straddle us amidships. Directly afterwards the Liberator flies in from the port bow. I open fire. My twin machine-guns shoot well and the aircraft crashes in flames. My Wanze and Fliege have been shot out of action. Some time later the Senior Engineer reports all clear for diving on one electric motor, so I order all hands below and commence return passage…”
On that first night, one schnorkel and five non-schnorkel boats reported that they were returning because of damage, while U.970 and U.955, the latter returning from the Atlantic, were sunk. Towards the morning of the 7th we deemed it necessary to allow the boats to proceed to their stations submerged, and their daily run was thereby reduced to 50 or 60 miles; however, despite this relaxation, two more boats - U.629 and U.373 - were lost and two others damaged on the following night. By 10th June, two of the nine non-schnorkel boats which had left Brest for the Plymouth area had been sunk, while five had been forced to return damaged, and it was clearly impossible for U-boats without schnorkel to reach the western part of the Channel. On the following day, therefore, the two boats still at sea - -U.740 and U.821 - were advised to return, but they failed to do so and were assumed to have been destroyed on their outward passage.52
435. Problem of employment of the non-schnorkel boats
The non-schnorkel boats which left Lorient, St Nazaire and La Pallice on 6th June were drawn up in a double reconnaissance line between the latitudes of Brest and Bordeaux, conforming roughly to the 200-metre line. On 8th June one of our meteorological aircraft sighted a south-bound convoy 120 miles west of Brest and, since this could have been an enemy landing force, the boats were moved in to the 100-metre line, whence they could engage more speedily. Some hours later these ships were identified as fishing vessels; nevertheless, the boats were retained on the 100-metre line, for here they could lie on the bottom for long periods and thereby shorten the time needed for recharging batteries. Normally they were forbidden to bottom in less than 100 metres of water; but this ban was now lifted, since the danger from ground mines was regarded as less than that from air attack while on the surface. Although this procedure reduced to a minimum the time spent on the surface, the boats were still located and attacked on almost every night; but we dared not recall them to harbour, because a further enemy landing, or the mining of the approach channels, could have trapped them there. We therefore chose the lesser evil and left them exposed to the danger of air attack at sea. By 12th June it was evident, from the strength in which the enemy had landed in Normandy, that the danger of an immediate landing on the Biscay coast had passed and the boats were recalled to harbour, where they remained at six hours’ notice.
Their future employment was the subject of long discussion, and the question arose as to whether it might not be more expedient to send them into the Atlantic rather than keep them idle in harbour, even though their prospects against convoys would be extremely poor, for their appearance in the Atlantic might well induce the enemy again to employ his independent hunter groups in that area, from where they had been withdrawn to the Channel. However, FO U-boats believed that the enemy possessed sufficient A/S vessels to render such a withdrawal unnecessary and that he was still able to provide his Atlantic convoys with, at least, close escorts and escort carriers. In the Flag-Officer’s opinion, therefore, the sending of nonschnorkel boats to the Atlantic would result only in further heavy losses, whereas, by keeping them in western France we still had some prospect of inflicting damage on the enemy in the event - still a possibility - of his invading the Biscay coast.
“… Two years ago it was true to say that Norway had to be defended in American waters; that is, where we could sink the greatest tonnage. This precept is no longer valid. Today it is more important to sink one LST in the invasion area than, say, one Liberty ship in the Atlantic…” (385).
The boats therefore remained in their bases, while the work of equipping them with schnorkel was pressed on with the utmost vigour.
436. Precautions against an enemy landing in Norway
In the opinion of the German Naval Staff, the British invasion forces still remaining in Scottish and English coast ports on 8th June were sufficient for a secondary landing on the Norwegian coast, and hence they considered that the threat to Norway persisted.
By virtue of the rugged nature of the Norwegian coastline, the boats of group Mitte were in less danger of being trapped in their bases through an enemy landing, or by minelaying, than those of group Landwirt. However, there were too few reconnaissance aircraft available in the area to guarantee the sighting of an approaching landing force in sufficient time, and so a large number of U-boats had to be used for reconnaissance duties in Norwegian waters, for which they were ill suited. Between 8th and 10th June, 11 boats of group Mitte put to sea and, together with those boats already on patrol, formed a reconnaissance line from Trondheim to Lindesnes. Additional boats from Kiel later brought the strength of the flotilla up to 30, of which 16 were kept at sea. The patrolling boats suffered from frequent air attacks and they were therefore ordered to remain submerged, except when recharging batteries; the depth of water was too great to permit lying on the bottom, but some of them took advantage of density layers to drift, stopped and trimmed. Nevertheless, despite all precautions, two boats from group Mitte and four Atlantic-bound schnorkel boats fell victim to enemy aircraft during the month . Towards the end of June, as it became obvious that the threat to Norway had greatly diminished, the number of boats on patrol between 57 and 61 degrees North was reduced to five. Concurrently, nine boats of group Mitte were paid off and their crews drafted to the 23rd and 24th Flotillas, for manning the new Type XXI U-boats.
437. Considerations concerning the use of schnorkel boats in the Channel
Since the enemy had chosen to establish his bridgehead in Seine Bay, it was abundantly clear that only schnorkel boats had any chance at all of attacking his supply traffic, and that even they would be running a grave risk in so doing. FO U-boats, although outwardly confident, was haunted by the fear that he had demanded the impossible from his crews. We had had too little operational experience with the schnorkel to lay down hard and fast instructions for its use, or to state what procedures should be adopted in the presence of numerous A/S vessels; we did not even know if the boats would find the time to schnorkel-charge their batteries while operating in such a limited and populated area. No operational experience had been gained in the shallow waters of the Channel since 1940; it was a year since we had operated in American coastal waters; and, for all we knew, the enemy might now possess depth-charges or other weapons of such devastating effect in shallow water that a U-boat’s detection would ensure her destruction. Thus the boats, fitted with a schnorkel installation with which they were still unfamiliar, were being sent to face an unknown threat in an area considered, even in 1940, as too dangerous for such operations.
Operational control was rendered difficult and onerous by the problem of communicating with U-boats, even in normal operations, and during group Dragoner’s brief sortie into the Channel in May there had been many instances of boats missing important messages through having to schnorkel, despite careful timing of long-wave routines. It was most likely, therefore, that in the present circumstances the boats would have few opportunities to transmit, and that the Command would have to rely entirely upon radio intercepts and the reports of returning commanders for a picture of the situation. Such intelligence could be long out of date, and it is not surprising that we were unable to make up our minds on the viability of U-boats in the Channel, either before or after the invasion.
438. Twelve schnorkel boats against the invasion
The absence of an accurate assessment of the situation imposed an additional burden of responsibility on FO U-boats. His decision to use the schnorkel boats was influenced by the fact that, of all the weapons at our disposal, the U-boat was the only one capable of destroying any considerable quantity of the enemy’s invasion supplies before they had been landed; and, when balancing the amount of ammunition carried in a supply ship, or the number of tanks in an LST, against the cost in German lives and material needed to destroy these once they had been landed, there could be only one conclusion, namely, to attack the supply traffic with every available U-boat.
This requirement overruled our reluctance to use those schnorkel boats joining direct from Germany, which were on their first operational cruise and usually reached the approaches to the Channel only after a strenuous three- to four-week passage; indeed, to reduce this transit time, four of these boats were ordered to proceed surfaced, at high speed, as far as the latitude of the south of Ireland and then to continue into the Channel on schnorkel. One other was sent to the North Channel and another to the Minch, with the object of tying down enemy forces in that area.
In the early stages of the Normandy landings only 12 schnorkel boats were able to take an active part against the enemy’s seaborne forces - eight from group Landwirt and the four mentioned above.
439. Experience of enemy countermeasures
“… Every enemy vessel supporting the landing, even though it may be carrying only 50 men or a tank, is a target. Press home your attack, even at the cost of your boat. Should it be necessary to close the enemy landing fleet, pay no regard to the danger of shallow water, mines or other hazards.
Each soldier and weapon destroyed before reaching the beachhead diminishes the enemy’s chance of victory.
A U-boat which inflicts losses on the invasion forces fulfils her highest mission and justifies her existence, even though she herself may be destroyed.” (386)
This grim order was carried by the boats when they sailed from Brest on 6th June. On the way out, that night, most of them came under attack from enemy aircraft and the next day brought them into contact with the surface groups, which were waiting for them just off the coast. The difficulty experienced in forcing a way through the ring of enemy warships was brought home to us by a report from U.984, which returned to Brest on 9th June. U.984 had been located on 7th, 30 miles north-west of Ushant, by a surface group which subjected her to a 24-hour depth-charge pursuit and almost exhausted her. She finally shook off her pursuers by heading for the French coast, and an extract from her log is of interest:
“… 8.6.44. 2000. Six miles west of Ushant. Although enemy radar is still audible, I decide to schnorkel a little to ventilate the boat. We have now been submerged continuously for nearly 42 hours without a change of air, and for the last 12 hours breathing conditions have been extraordinarily bad. The men have literally been gasping for breath. A certain amount of relief has been obtained by breathing through potash cartridges, with the aid of escape apparatus mouthpieces.
2212. I am now close to the coast, my batteries completely exhausted, so decide to return to Brest to recharge and top up with torpedoes…”
Similar experiences were reported by U.953, which entered Brest on 18th June, and by U.269, U.27S and U.984 (again), which all put into St Peter Port, Guernsey, between 13th and 18th. On 8th June, when 40 miles north-west of Ushant, U.953 had an encounter with a group of three destroyers, one of which bore the number H90, and claimed to have sunk all three;53 but, after developing a defect in her periscope, she was forced to return before reaching the operational area. Apparently the enemy had set up several patrol lines between Lizard Head and Ushant, and between Start Point and the Channel Islands, besides keeping a particularly sharp watch on French waters.
The use of St Peter Port by the three U-boats, for battery-charging, served to provide interesting proof of the excellence of the enemy’s intelligence system. Up to that time the harbour had been left unmolested by enemy aircraft; but a few hours after the arrival of each boat an attack was delivered by fighter-bombers, resulting in the loss of one patrol vessel and damage to two others.
We were greatly concerned at reports that boats had been bombed - and perhaps fired at - while schnorkelling at night, indicating that the schnorkel could be located and recognised by radar. In these circumstances it became even more difficult for the boats to find time and space for recharging their batteries, and we could only hope that no such accurate location and recognition would be possible amongst the dense traffic to be found in the actual area of operations. In view of these schnorkelling difficulties we refrained from restricting the boats to specific attack areas and merely detailed three to operate to the north and three to the south of the parallel 50° 10’ North, with freedom to cross this line if A/S and traffic conditions so demanded.
440. Great uncertainty over the situation in the Channel
Enemy radio intercepts on 11th and 13th June indicated that one or more boats had reached mid-Channel. But, as there was no further intelligence of this nature, and in the light of the reports of those boats which had returned, serious doubt soon arose as to whether the intercepts had referred to actual asdic contacts, or merely to the suspected presence of U-boats. This lack of further intercepted enemy action reports was particularly worrying, as it pointed to the possible destruction of any boats which had managed to reach Seine Bay. Because of this uncertainty and our lack of knowledge of the operational possibilities in the assault area, we examined the question of recalling to base those four boats approaching the Channel from Germany, which were now approximately south of Ireland, and of diverting the next four - at this time north and north-west of Britain - to attack areas to the west of the British Isles. However, in view of the necessity to exhaust every possible means in combating the invasion, we determined to keep to our original plan and send them all to the Channel.
On 17th June FO U-boats reluctantly decided that the next four Biscay-based schnorkel boats to become operational should be used to transport anti-tank and machine-gun ammunition to Cherbourg, which was now cut off and seriously threatened.
“… The U-boat is a complicated and highly developed instrument of war, wholly unsuited to transport purposes. My decision to employ them on this task is made easier by the fact that we are completely ignorant of the operational possibilities in the landing area…” (387).
The four boats duly sailed from Brest and La Pallice, between 20th and 22nd June, with 8,000 rounds of anti-tank and 350,000 rounds of machine-gun ammunition, only to be recalled on 23rd, because the entrance to Cherbourg harbour was blocked.
441. The recall of the U-boats from sea
The first positive information of conditions in the actual operational area was provided by U.621 and U.764, both of which returned to Brest on 22nd June. The former had, on 15th June, penetrated the screen of a convoy of six LSTs, to the north of Seine Bay, and had fired a spread of three torpedoes which all detonated prematurely; however, she later sank a straggler - LCP 280 - with a T5 torpedo. On 18th, in the same vicinity, prematures again robbed her of success, this time against a Valiant and a King George V class battleship. U.764 had, on 15th June, attacked and sunk the frigate Blackwood to the north of Jersey, but had then to return on account of damage.
Operational conditions appeared to correspond generally with our original expectations, the approach to the operational area proving very difficult, while the area itself offered considerable opportunity for successful attacks, with little enemy opposition because of poor conditions for asdic and radar location. However, these opportunities could not be fully exploited on account of torpedo failures and the U-boat’s low speed, and both boats reported being frequently passed over by convoys without an opportunity to attack them.
No further reports were to be received from the operational area until the beginning of July; so when, on 25th June, a four-day series of intercepted enemy U-boat sighting reports suddenly ceased, we wondered whether the A/S situation might have deteriorated since U.621 and U.764 left the area or, alternatively, whether these two boats might not have struck a particularly favourable period. Worried by this uncertainty, we decided, on 2nd July, to send no more boats to mid-Channel, and five, then passing through the western Channel en route to the operational area, were recalled to Brest, where they were to remain until the situation in the invasion area became clearer. Two of these, however, failed to arrive, and we presumed that they had been lost to the south of Ireland or while entering the Channel.54 In order to clarify the situation as soon as possible, the five boats which had been longest in the operational area were instructed either to transmit a situation report or to return to base forthwith.
442. Use of schnorkel boats justified by results
The first and, as it turned out, the only boat of the five to return from the Channel was U.894, which arrived on 5th July, and her Commanding Officer confirmed that operational conditions in the Seine Bay area were every bit as favourable as indicated hitherto. He reported that on 25th June, while 40 miles north of Jersey, he had sunk a frigate in an encounter with a surface group, British records showing that the vessel in question - HMS Goodson - was in fact damaged and towed back to harbour. He also claimed to have sunk two large ships and damaged two others from among a group of transports which he attacked on 29th, 30 miles north of Cape Barfleur; in this case British records show that he actually sank three ships totalling 21,500 tons and damaged one of 7,240 tons.
“… This proves conclusively that the U-boat is able to operate in the Seine area, and that introduction of the schnorkel has restored her efficacy in areas heavily patrolled by aircraft. Nevertheless, we must not lose sight of the fact that a schnorkelling U-boat is likely to be taken by surprise…” (388).
On 5th July, U.671 put into Boulogne. This boat was one of those which came direct from Germany and, in accordance with her instructions, had kept well in to the English coast on the final eastward run. She had reached the middle part of the Channel without difficulty; but on 4th July, while lying bottomed 20 miles south-west of Beachy Head, was detected - probably through an oil trace - and attacked with depth-charges, the resulting damage compelling her to make for the nearest port. As there were no U-boat technicians at Boulogne, a party of 30 was sent from St Nazaire and these men, working under great difficulties, had her ready for sea before the month was out.
In a contemporary assessment of the results of U-boat operations during the first four weeks following the Normandy landings, we found that of 12 boats which left Brest for the Channel in June - -10 with torpedoes and two with mines - three had been destroyed and two had failed to reach the operational area. Judged by conditions prevailing in 1944, these losses were quite tolerable, but matters were entirely different in the case of those boats arriving direct from Germany; of these, only two had survived - U.671 and U.480 - while two were presumed to have been destroyed in the Bay of Biscay and four in the western Channel. It has since been established that one was lost in the Bay, three in the western Channel and two in the centre part of the Channel. Such heavy losses proved that we had given too difficult a task to these inexperienced crews and quickly scotched any idea of routeing boats from Germany via the North Sea and Dover Straits, a step which was being seriously contemplated.
The factual reports from U.984 and U.671 decided us to continue operations in the Channel, but only with boats based in Western France. During the first four weeks of Channel operations, U-boats had sunk five ships totalling 30,994 tons - including an LSI(H) - and two frigates, and had damaged one ship of 7,240 tons and one corvette, for the loss of a good 500 men of the U-boat arm. Expressed in terms of supplies lost to the enemy, these sinkings, alone, would have warranted an even greater sacrifice on behalf of the German army in its grim, bloody defensive battle. Furthermore, as, from now on, only experienced crews would be sent into the Channel, it was reasonable to expect that losses might remain within tolerable limits.
JULY 1944
TIGHTENING OF THE ENEMY BLOCKADE OFF THE BISCAY COAST
443. Conditions in the Channel continue favourable
The capture, at the beginning of July, of an enemy track chart and an accurate appreciation of our U-boat, E-boat and air activity, furnished us with a fairly good picture of the enemy’s supply organisation. Nine convoys left from each side of the Channel daily and, of those bound for France, four sailed from Portsmouth, three from the West of England and two from the Thames, following buoyed routes and times to arrive in the unloading area between 1400 and 1800, while it was still light. There were no night sailings. The routes were protected on their flanks by destroyer patrols, while the convoys themselves were usually escorted by motor-launches. Ships and escort vessels often towed kite-balloons as protection against low-flying aircraft, and these balloons sometimes enabled our U-boats to spot a convoy, through the periscope, at long range.
The A/S defences in the area lying between Seine Bay and the Isle of Wight were far less dangerous than in the western Channel and, during the last two weeks of June, after three successive boats had been pursued almost to exhaustion in the latter area following attacks on surface groups, orders were given to refrain from attacking A/S vessels and to concentrate on invasion supply ships.
Throughout July schnorkel boats continued to be sent to the Channel, as they became ready for sea; but, since we had no idea of when losses occurred, the number of boats in the operational area was overestimated at about six, whereas the actual figure had been between three and four. By 21st July four more boats had returned and, between them, claimed to have sunk three ships totalling 20,000 tons and two destroyers, with a further three ships and one destroyer damaged; but British records show only two ships totalling 3,426 tons and a trawler sunk. Mines had been laid by two of these boats, U.214 laying 16 SMA off Plymouth, which damaged one ship of 7,177 tons, and U.218 a similar number off Land’s End. Only two of the boats had encountered strong enemy opposition, the others practically none. All four Commanding Officers were optimistic in regard to prospects in the unloading area, where the great concentration of shipping made detection less likely, and considered that the effect of the enemy defences depended chiefly on the luck and skill of individual U-boat commanders.
444. Schnorkel routine and disposal of refuse
Only through the verbal reports of individual commanders did we learn of the hardships suffered by the crews during their three- to four-week sorties. In daylight, which lasted for nearly 20 hours out of 24, they dared not raise the schnorkel to ventilate the boat; consequently the atmosphere, which was always pretty foul in a schnorkel boat, was further polluted by the stench of decaying waste food and other refuse. A few boats had been equipped with a new type of air-pressure WC, which included a sump and large-bore discharge pipe through which waste matter could be evacuated after being chopped up; others tried to solve their problem by packing refuse into tins and laboriously disposing of them at night through the Bold55 discharge tube. But in July one commander hit upon the idea of stowing all his refuse, including packing cases, in an empty torpedo tube and firing it every three or four days. Of course, the tube could no longer be used for its proper purpose and had to be isolated so as to avoid fouling the remainder; but this procedure, known as a Müllschoss (rubbish shot), was subsequently adopted by most of the boats, and thereafter, when a boat returned to base, the first dockyard workmen to arrive on board no longer recoiled from the open hatch.
Since every man’s movement consumed oxygen, a boat’s routine was usually adjusted to the schnorkelling pattern - clean ship, torpedo maintenance and meals being put off until the night schnorkelling period, when there was sufficient fresh air for all. For most of the time and unless on watch, crew members generally lay on their bunks, and a few commanders even extinguished the lighting to discourage conversation and other oxygen-consuming activities.
445. Ordeal in the Channel
This last mentioned measure was psychologically unsound, since it allowed the minds of the crew to dwell too much on outside noises. In these Channel operations, the din endured by the U-boat crews surpassed anything experienced hitherto; the buzzing and screaming of various types of noise-box, the pinging of asdic and the whirring of propellers were continuous, while the detonations of innumerable bombs and depth-charges shook the boat as a constant reminder of the enemy’s presence. It was almost impossible to estimate the range of a noise-source; the faintest humming could spell danger, and a sustained noise often drowned the whirr of approaching propellers. On occasion, a destroyer would suddenly be heard directly overhead, or depth-charges would explode nearby without warning. Even the bravest - and one must grant that these pale-faced U-boat men were brave - could not fail, eventually, to become adversely affected by such conditions.
A U-boat could find herself in very serious straits if hunting vessels remained in her vicinity and gave her no opportunity to ventilate between decks, as illustrated by the following extract from the log of U.763, for 6th July 1944:
“… 1645. South of Isle of Wight. Bottomed again in 55 metres. Enemy still has contact. I shall wait here till night. Depth-charges are now fewer and further between. Thirty-four detonated in our near vicinity between 1600 and 2000. Despite the addition of oxygen and the use of potash cartridges, the air has become perceptibly fouler. A very great quantity of air was consumed by members of the crew who had to be moved in order to keep trim during my attempt to shift position. The crew are becoming more exhausted. It is nearly 30 hours since the boat was last ventilated. The first cases of vomiting occur, and I issue each man with a potash cartridge. Breathing becomes distressed. The enemy search group is still active overhead… The intervals between depth-charges are getting longer, but detonations are nearly all very close… During the 30 hours of the pursuit, 252 depth-charges were counted in the near vicinity, 61 at medium range and 51 at long range…”
A schnorkel failure or defect could also cause serious difficulty, as is illustrated by the experience of U.218, on 20th June, during her minelay off Land’s End:
“… 0400. Bomb or depth-charge concussion has apparently fractured a tappet lever on the port diesel. Starboard diesel started; but owing to insufficient exhaust pressure the safety valve lifts and the exhaust gases escape into the boat, filling all compartments and necessitating the wearing of escape apparatus.
0500. Surfaced to ventilate the boat.
0503. Naxos gives three separate warnings, amplitude 4 to 5. Dived to 80 metres.
1200. Several men suddenly taken ill during the forenoon. By noon two-thirds of the crew are suffering from severe headache and stomach-ache, nausea and retching and are no longer fit for duty. The remainder, also complaining of bad headache, keep things going. There are several cases of fainting through over-exertion and carbon-monoxide poisoning.
1230. Rise to periscope depth in an attempt to ventilate with the port diesel.
1240. Port diesel starts, but exhaust pressure is too low to empty the schnorkel mast. The safety valve lifts again, filling the boat with exhaust fumes which cause further cases of poisoning.
1250. Electric compressor started in an attempt to draw out the fumes and replace them through the schnorkel valve. The state of the crew continues to deteriorate.
1400. Surfaced to change the air in the boat. I cannot wait until dusk.
1406. Dived. The boat is thoroughly ventilated. By evening there is only a slight improvement in the state of the crew. Milk is issued to counteract the effects of the poisoning. Six men, in a state of collapse, given injections of lobelyn sympatol to stimulate heart action…”
446. Difficulties of navigation in schnorkel operations
The constant battle against the enemy defences called for the greatest determination and physical and mental toughness on the part of the U-boat commanders. This meant the employment of younger men, and in 1944, with most of the senior commanders either dead or forming the backbone of training establishments and shore commands, their ages ranged between 23 and 26. These young officers had received their commands after only four to seven years’ service and few of them had any experience of navigation in difficult tidal waters; the same was true of the navigators, nearly all of whom joined their boats direct from training school. Moreover, in these Channel operations and, later, in operations in British inshore waters, commanders and navigating officers had to cope with the added difficulty of continual submergence.
The periscope could, of course, be used for terrestrial navigation, but with the object lens so close to the surface it was necessary to approach very near to the shore; the commanders fought shy of this, for the risk of destruction by mine or A/S forces was greater in depths of 15 to 30 metres.
A device for taking star sights by periscope was only in the development stage. To obtain a fix by radio beacon, the boat had to surface sufficiently to bring her frame aerial above water, in which state the conning tower was exposed to location and attack from the air. Speed in operation was therefore vital, but, as a number of these beacons had been destroyed by bombing and others were frequently out of action for various reasons, it usually took some time to obtain a fix and commanders understandably, seldom ventured to expose their boats for so long. In these circumstances they had generally to navigate by dead reckoning - a difficult task, since, apart from Hurd Deep, there were no well defined depth lines in the Channel; furthermore, the tidal rates and directions given in the Tidal Atlas were primarily for surface navigation and not for the water strata between 30 and 50 metres below the surface in which the boats normally operated. The tides were sometimes so strong that the boats had difficulty in intercepting a convoy, or even remaining in a selected position, for a submerged U-boat could not anchor to prevent herself from drifting and only around the time of slack water could she rest on the bottom, trimmed by the bow, allowing her stern to swing with the tide. On occasions when their batteries became exhausted, commanders were compelled to seek bottom regardless of the state of the tide and to risk damage to rudder and screws, by dragging.
Despite all these difficulties, the boats would probably have managed to fix their positions with reasonable accuracy, had not navigation frequently to be sacrificed to tactical need. If A/S vessels happened to be searching in the vicinity, gyro-compass and echo- sounder had both to be switched off to reduce noise, and after some hours of dodging here and there neither commander nor navigator had any idea of their position; consequently the U-boats sometimes found themselves in awkward situations.
447. U.763 drifts into Spithead
The experience of U.763, between 7th and 8th July 1944, will probably remain unique in the history of the U-boat. The following is an account from her log:
“… 7.7.44.1200. After having been pursued with asdics and depth-charges for nearly 30 hours, our greatest worry is the fixing of our position. No echo-soundings could be taken during that time and our alterations of course and the set of the tide have taken us a considerable distance. Dead reckoning puts us 20 to 30 miles north of Cherbourg…
1654. Touched bottom (40 metres).
1902. Bottomed in 40 metres. This shallow depth makes me wonder if we are actually further to the southward. There is a 9-knot current there. Though we are trimmed by the head, the boat is lying very badly. Rise to periscope depth. Course 330 degrees. Land in sight to port, bearing 300 degrees true…
2258. It is beginning to grow dark. As visibility is bad to starboard, I can make no further check. There are no stars. From a study of the chart it appears certain that the current has carried us between the Channel Islands. Sounding continuously and utilising the northerly set, I try to schnorkel clear to the northward. Visibility ahead is good enough…
8.7.44. 0041. The soundings do not agree with the chart. An attempt to fix by radio beacon produces one position only (Brest), which passes through the area in question and, together with the soundings, appears to confirm our estimated position. So long as I have sufficient water and visibility there is no point in surfacing. Carry on schnorkelling in order to have the batteries sufficiently charged, by daylight, to enable me to obtain a fix at periscope depth.
0337. Touched bottom (16 metres). Stopped schnorkelling. I determine to surface, since our estimated position cannot possibly be correct. The farther we proceed to the north-west the shallower the water becomes, whereas according to the chart it should become deeper. I wonder if the echo-sounder is reading correctly.
0356. It is almost a flat calm, moonlight and misty. Surfaced… About two and a half miles on the port quarter, four destroyers are lying in the moonlight. Land lies on both beams. The shapes of several steamships are visible to port. I turn off to the north-west, assuming that I have the enemy-occupied Cotentin Peninsula to starboard and the Channel Islands to port. The echo-sounder must be out of order and the current must have carried us into shallow water.
0433. Submerge again when the echo-sounder shows 30 metres. Bottomed at 35 metres. After pondering over what I have seen, it suddenly occurs to me that we have fetched up close to the English coast. The direction of the Brest position line on the chart shows that in all probability we are at Spithead, however unlikely that may sound…”
That night and the following forenoon U.763 remained bottomed a few miles north-west of the Nab light.
“… 9.7.44 1525. Left bottom.
1548. Periscope depth at silent running speed. Using the periscope sparingly and just awash, I discern three small vessels anchored in the stream.
1605. An anchored landing craft - US 264 - lies on the starboard beam, and ahead of her the hospital ship, No. 62. I pass between them to the other side where, on the port bow, I sight two old 2,000-to 3,000-ton steamers, in ballast, lying at anchor. On south-easterly courses the water becomes shallower. A fix by cross-bearings shows that I am in danger of being left high and dry by the tide. I therefore turn about and make for a 20-metre patch.
1802. Bottomed again in 17 metres. Low water is at 2204, so that I am no longer in danger of being stranded…”
Despite the opportunities that presented themselves - though there were no really worth-while targets - the Commanding Officer could not attack for fear of his Lut torpedoes running ashore and falling into enemy hands.
“… We have inexplicably got the boat in here unnoticed and will get her out intact, for she must not fall into enemy hands.
2220. Action stations…
2250. Leave bottom. Rise to periscope depth. I keep to the starboard side of the fairway. Returning landing craft and what I presume to be two destroyers, pass us on the opposite course…
2338. Course 140 degrees. We have not been observed. The water gets gradually deeper…
From the Commanding Officer’s observations we saw the possibility of penetrating into this area to lay mines. Indeed, such an operation was planned, but it had to be dropped because of the subsequent evacuation of the Channel.
448. Enemy starts close blockade of the Biscay coast
At the end of June, enemy light naval forces operating at the western entrance of the Channel transferred their attention nearer to the Biscay coast and, on 6th July, a small force of destroyers attacked one of our outgoing U-boat convoys off Brest, sinking two of the escorts. Thus began a gradual enemy infiltration into the Bay of Biscay coastal waters and, since our own defence vessels were too weak to give battle, there was nothing we could do to stop it; moreover, we had no air reconnaissance at our disposal. Having encountered no opposition, enemy squadrons gradually felt their way southwards, until by the end of July they were operating off La Pallice and Bordeaux with the same immunity. In these circumstances, rendezvous positions for U-boats and their escorts were shifted back into those areas covered by our coastal batteries, but even so the enemy continued to sink so many of our escorts that, eventually, the U-boats had to sail and return from operations unescorted. The Senior Officer U-boats West made some attempt to counter these surface attacks by stationing two schnorkel boats off Brest for two days at a time - i.e. for as long as they could remain without charging their batteries - and passing to them by radio the positions of radar-located destroyers; but this information always failed to agree with the observations of the boats themselves, so that doubt arose as to the accuracy of our radar ranges. These boats kept guard from 8th July to 2nd August without a single success.
The deterrent effect on the enemy of even minor counteraction was demonstrated by two Luftwaffe attacks on enemy formations off Brest, on 20th and 21st July, in which one destroyer was sunk and a cruiser damaged;56 whereafter the enemy behaved more cautiously for a few days and kept well clear of the coast. But a little later, when it became clear to him that these Luftwaffe attacks had been only a flash in the pan, he resumed his inshore operations, with the result that we had to abandon our entire patrol system and to confine our swept channels to within the 200-metre line.
AUGUST-SEPTEMBER 1944
EVACUATION OF THE ATLANTIC BASES
449. Evacuation of Brest, Lorient and St Nazaire
The American breakthrough at Avranches on 4th August threatened the three northern Biscay bases with encirclement, and steps had therefore to be taken to evacuate the U-boats in good time. The primary requirement was to complete those boats currently fitting out with schnorkel at Brest, Lorient and St Nazaire, while those for whom there was no gear available in these bases were made ready for sea and sailed for La Pallice or Bordeaux, the opportunity being taken also to transfer experienced dockyard and specialist personnel, together with essential material such as schnorkel components, T5 torpedo testing gear and non-ferrous metals. The U-boat personnel remained in the three northen bases, above all those whose boats were undergoing extensive refits and could not complete in the near future, were, as far as the land battle permitted, returned to Germany.
Subsequent to the enemy breakout, the situation deteriorated rapidly and our scanty forces in Brittany, retreating before the advancing enemy spearheads and the Maquis, hastily withdrew into the coastal fortresses. This influx of troops, many of whom, demoralised and undisciplined, sought shelter from enemy bombing in the U-boat bunkers, caused such disruption to work on the boats at Brest and Lorient that the latter’s completion became doubtful. Furthermore, the army’s erroneous and pessimistic evaluation of the general situation gave the impression that Lorient could not be held for long, whereupon the Senior Officer of the local flotilla, on his own initiative, sent several U-boats to sea; and only through the intervention of the Supreme Command was some semblance of order restored, allowing work on the U-boats to proceed.
On 6th August enemy spearheads had penetrated to within 20 miles of Angers, the headquarters of SO U-boats West, who was thus forced to evacuate to La Rochelle. Until the evacuation was completed on 8th, U-boat Command temporarily assumed control of operations in the Channel. This move had its compensations in that SO U-boats West was thereafter in close contact with his forces, allowing him, in the event of precipitate action by the military authorities, to take such measures on behalf of the U-boat arm as he thought fit.
450. Transfer to bases at La Pallice and Bordeaux
The transfer of U-boats from the three northern bases to La Pallice and Bordeaux proved to be a most hazardous undertaking. The enemy had apparently been warned of our intention and, quite understandably, used every means to destroy the boats during their passage, which, having no torpedoes, were unable to strike back. With enemy air and surface forces ever present, navigational accuracy was bound to suffer, and Commanding Officers were frequently unable immediately to find the escort that should have been awaiting them off their port of destina- tion; consequently, and in view of the fact that escorts dallied at the rendezvous for only a short while before returning to harbour, the boats had generally either to ensure an early arrival, so that the approach of the escort might be picked up by hydrophone, or to proceed into port unescorted. A few of them chose to withdraw to seaward for the time being, thereby re-entering the sphere of the hunter groups.
The danger experienced from aircraft and mines, even in the near approach channels, is well illustrated by the following extract from the log of U.309:
“… 12.8.44. 0345. Approaching escort rendezvous off La Pallice in company with U.981.
0415. U.981 mined. I send the following signal: ‘U.981 mined. Incapable of diving. Everything out of action. Request escort at rendezvous forthwith. U.309’.
0620. Lying stopped with U.981, whose engines are still out of action. Halifax aircraft approaches, passing over us three times and dropping flares. U.981 now able to proceed on electric motors. We proceed at slow speed, steering 090 degrees, parallel with the line of buoys.
0624. Bomb attack on U.981… A further attack from the Halifax. The AA fire of both boats lies well on the target. A second mine detonates alongside U.981, which is again bombed by a twin-engined aircraft. U.981’s diesels suddenly spring to life and she sheers off course.
0643. U.981 is clearing away rubber dinghies. She starts to sink. Her crew are jumping over- board. I close her and pick up 40 survivors…”
The transfer of U-boats to the southern ports was completed by 21st August. Of a total of 16 boats which left Brest, Lorient and St Nazaire, seven (two schnorkel and five non-schnorkel), or about 50 per cent, failed to arrive; and these heavy losses were all the more painful when it was dis- covered that most of them could have been avoided. In the event, once the enemy had broken out of the beachhead and had started to advance rapidly into Brittany, the German High Command expected that he would drive for the ports, which were urgently needed for the unloading of immense quantities of supplies; however, available Allied forces were apparently considered inadequate to this task and, with the exception of Brest, the U-boats could have remained in their bases to complete repairs, before being sailed direct to Norway.
451. Effect of bombs on U-boat bunkers
The ultimate concentration of U-boats in the bunkers at La Pallice, Brest and Bordeaux evoked heavy bombing by strong enemy formations between 9th and 13th August. The bunker at Bordeaux received 26 direct hits from 11,000-lb bombs, but only superficial damage was caused to the roof, which consisted of two thicknesses of reinforced concrete, one of 6.2 metres beneath a “burster course” of 3.5 metres. At Brest, the 5.6-metre roof of the bunker, which then had no “burster course”, was partially penetrated in three places by extremely heavy bombs - estimated at six tons - one of these breaches being 10 metres in diameter and the others, situated over the dividing walls, small. The U-boats in the bunker were unaffected and only slight damage was sustained by bunker equipment. Specialists from the Todt organisation, who afterwards inspected the bunker at Brest, considered that, given a 3.5-metre “burster course”, the roof would have withstood the heaviest bombs then known to exist. This inspection yielded valuable information, which was at once applied to the design of U-boat and dockyard bunkers currently under construction in Germany.
The last air attacks on the Biscay U-boat bases, in which all unprotected dockyard equipment was completely destroyed, provided conclusive proof of the vitally important role played by the U-boat bunkers since 1941. We wondered, indeed, why in 1941 and 1942 the RAF had not attempted to disrupt their construction, for at that time neither our AA defences nor our fighter force could have offered effective resistance to concentrated attacks. Continuous raids on the then unprotected bases would have so impeded U-boat repair work that, by the end of 1942, the U-boat campaign would have been rendered ineffective.57
452. Recall of the U-boats from the Channel
By 11th August two more boats had returned from the Seine area, where they claimed to have sunk six ships and damaged two; British records show, however, that only one LST was sunk and two ships totalling 17,180 tons damaged. According to these commanders, both the traffic situation and opportunities for attack were still as good as ever; but enemy activity had intensified. This latter assessment was reinforced by the experience of U.309, which, her batteries run down and her crew exhausted, had had to return after only six days in the operational area, and by that of U.275, which was forced to put into Boulogne, badly damaged. That enemy opposition had indeed increased seemed all the more likely since several other boats were overdue.
All in all the situation was far from satisfactory, and by 20th August we were beginning to wonder if there were, in fact, any boats left in the operational area, for there had been no recent intercepts of enemy sightings of, or attacks on, U-boats, while British broadcasts had announced the sinking of three, including one destroyed in an alleged attempt to break through the Straits of Dover from west to east.
Eight schnorkel boats were approaching readiness in western France; but in the existing circumstances, instead of sending them as reinforcements to the Seine area, we allocated these boats to the Bristol and North Channels, assuming that opposition there would be weaker. In occupying the Bristol Channel we were influenced by a radio report made on 22nd August by the returning U.667, which had been operating off the north Cornish coast since the end of July, claiming to have sunk a destroyer and 15,000 tons of shipping.58 Unfortunately, we received no intelligence on the A/S situation in that area, as U.667 was destroyed by a mine on 25th while entering La Pallice.
As a final step, between 24th and 26th August we ordered the seven boats estimated to be still in the Channel to return to Norway and, to our great relief, five of them reported themselves subsequently. They claimed good results, aggregating one destroyer and five ships of 22,800 tons sunk and another ship damaged, while British records show that five ships totalling 17,635 tons and the minesweeper Loyalty were sunk, and two ships totalling 12,821 tons damaged.
453. Good results from Alberich
Of the last six boats to operate in the Channel, U.480 distinguished herself by sinking a minesweeper - HMS Loyalty - and about 14,000 tons of shipping. She was the second Atlantic U-boat to be treated with Alberich - a coating of rubber designed as a protection against asdic location - and the following extracts from her log give an excellent idea of the conditions in the Channel at that time:
“… 18.8.44. 0257. North of Seine Bay. My intention is to make for the buoyed route with the westerly current; there to lie on the bottom until 1630 - the time at which the previous observation has shown traffic to be at a maximum - when I shall rise to periscope depth, heading the current and using my motors as necessary to remain hove to in sight of the chosen buoy. I shall attack only largeish ships…
0653. Bottomed one mile south-west of buoy situated 34 miles north-west of Cape Barfleur…
1500. North-bound convoy suddenly passes overhead… To explain the situation in the operational area, let it be said once more that barely five minutes pass without the sound of depth-charge detonations. Asdic impulses are constantly audible on all bearings. The noises made by ‘circular saws’ and sonic buoys59 complicate our hydrophone listening, so that it is often impossible to use the hydrophone tactically. Machine-gun and pom-pom fire is frequently audible, apparently fired by patrol vessels. Landing-craft are to be encountered everywhere, not only on the defined routes, so that by day it is almost impossible to identify a convoy by hydrophone…
1530. Left bottom. Hove to at periscope depth…
2050. Since my expectation of an evening convoy is unfulfilled, I head away to the eastward, with the current, to schnorkel. In future I shall carry out the same procedure every afternoon, since I regard this as the only way of coping with these difficult tidal conditions…”
U.480 sank the ss St Enogat on 19th August and HMS Loyalty on 22nd. She was passed over by convoy FTM 74 on 25th, from which she sank a straggler - ss Orminster - with a T5 torpedo, and was then hunted for seven hours.
“… 25.8.44. 1508. Am being pursued by four A/S vessels, two of which are operating asdics; the third, which apparently acts as depth-charge dropper, approaches at intervals of from five to ten minutes and drops charges; the fourth can be heard to be running her engines at very low speed. Listening conditions are particularly good.
2140. Beginning of dusk. Pursuit lasts until 2200, during which time we have covered five miles over the ground. I have stopped the gyro and refrain from using the hydrophones. I maintain my depth by shifting the crew. One of the A/S vessels frequently lies directly above us with her engines just ticking over, when the least sound aboard her is clearly audible and asdic impulses are extremely loud. In these circumstances, any boat with a mechanical fault which causes the smallest noise must, at all costs, locate and rectify it. The depth-charge dropper, which has lately been lying stopped, approaches and drops five or six depth-charges, at intervals. These cause such trivial damage that I am convinced that the enemy is unable to locate us by asdic and so is without an accurate range. He has merely a hydrophone contact which, because of the absence of noise in the boat, is bound to be vague. I attribute the enemy’s failure to locate me, mainly to the protection afforded by Alberich…”
454. Losses in the Channel justified by results
Our final assessment of the U-boat effort in the Channel and off the Cornish coast showed that in the period 6th June to the end of August, a total of 30 schnorkel boats took part in 45 sorties, their achievements in both areas amounting to:
|
As Estimated By |
As Shown By |
Sunk |
12 escort vessels totalling 112,800 tons |
5 escort vessels totalling 8,404 tons 12 ships totalling 56,845 tons |
Damaged |
1 escort vessel totalling 44,100 tons |
1 escort vessel totalling 36,000 tons |
These U-boats also carried out three minelaying missions which, according to the Britis’ records, resulted in the sinking of one and damage to two ships. Twenty U-boats were destroyed Related to the number of sorties, these losses amounted to 45 per cent, to the number of boat employed, 66 per cent. This high percentage was not, however, so serious in itself, since the 20 boat concerned were, after all, obsolete by this time. The loss of 1,000 men, of whom 238 - or about 2 per cent - were picked up by the enemy, was also not too high a price to pay for the results actuall achieved.
Having regard to the fact that nearly all the ships sunk were carrying war supplies, the validit of the following contemporary appreciation by FO U-boats cannot be denied, even in retrospect
“… 15.9.44. Our U-boat effort in the Channel is thereby terminated, and the old fighting spirit of the U-boat arm has again magnificently stood the test. A comprehensive survey of operation shows that, contrary to our initial misgivings and the doubts that assailed us during the course c the operations, we were right in employing the U-boats. Considering the extremely difficult operating conditions, the results achieved were good and losses tolerable, though heavy. Despite the fact that our blow at the enemy’s supplies was indecisive, it was certainly severe and helped to relieve pressure on our troops ashore. Besides achieving tangible results, we also gained experience and knowledge of continuously submerged U-boat warfare which will be of great value, particularly for the new-type boats. We also tied down considerable sea and air escort forces, which would otherwise have been available for purposes such as the disruption of our supply traffic off the Dutch and Norwegian coasts, as well as for intensive air attacks on our lines of communication on the Western Front. Results would have been better and losses certainly lighter, had the boats been possessed of higher submerged speed and a greater endurance; the fact that these very qualities have been highly developed in the new-type boat gives us good hope for the future. The schnorkel was, in effect, decisive, and operations in these areas would have been out of the question without it. No one would have believed a few month ago that a U-boat could proceed submerged for 42 days without surfacing. It is the schnorkel alone, which now enables us again to operate close in to the British coast, and to continue using the older boats until the new-type are ready…”
455. The withdrawal to Norway
Several boats were still under repair in western France and, until such time as they were completed, the flotilla staffs and dockyard personnel had to remain behind; eager to return to Germany, the dockyard workers finished most of this work well ahead of the estimated date. Other boats, which had been paid off at Lorient and St Nazaire, were remanned and, after being temporarily; patched up, were sailed for Norway, some of them leaving with schnorkel masts fixed in the vertical position or with torpedo tubes blanked off. A few serviceable schnorkel boats also left for Norway there being no reliefs for their sick commanders. The only boats which, through lack of batteries could not be made ready for sea - U.123 and U. 129 at Lorient and U.178 and U. 188 at Bordeaux-were paid off and later scuttled.
After the last U-boat had left Bordeaux on 25th August, there was no further need to defend that harbour, and the base personnel were dispersed. Part went to reinforce the garrison at La Rochelle and the remainder, made up of some 20,000 naval and dockyard hands, formed a battalion which was detailed to return overland to Germany; but only a small proportion of the latter managed to fight their way through to the German lines, the majority falling prey to Allied troops or the Maquis.
The SO U-boats West, whose ultimate duties were limited to getting the boats to sea, was flown back to Germany and, after a brief period at U-boat Headquarters, he and his staff transferred to Norway to take over the administration of the operational Atlantic boats and to assume responsibility for base, dockyard and convoy matters.
From the middle of August a total of eighteen U-boats left the Biscay bases for Norway, the last to leave being U.267, which sailed from St Nazaire on 23rd September. The only boat to be lost was U.445, presumed sunk early on in her passage through the Bay. The general success of the operation was taken to indicate that the enemy had by then tightened up his blockade of the western Channel at the expense of his watch in the Bay itself. Quite a number of dockyard technicians and specialist naval officers took passage in the departing U-boats, while the U-boat personnel who remained behind were absorbed into the land defences, where they distinguished themselves by their toughness and courage.
OTHER AREAS
456. Schnorkel boats in British coastal waters
There were no U-boats in the North Atlantic from July to September 1944, apart from a few engaged on meteorological duties, the main reason being a lack of schnorkel equipment, coupled with the decision of 1st June not to send further non-schnorkel boats to that area.
Of eight schnorkel boats which sailed from Norway in June, four went to the Channel and the rest - U.423, U.478, U.715 and U.1225 - were all lost en route to the Atlantic. Certainly the waters through which these boats had to pass were heavily patrolled, but the schnorkel should have taken care of that problem. We were therefore forced to assume that, with crews only imperfectly trained, the boats in question had occasionally found it necessary to surface, an assumption supported by comparison of their plotted positions with those contained in intercepted British radio messages. A typical example lending weight to this theory was provided by U.865, which, between June and August, had been forced on four occasions to break off her passage owing to schnorkel defects, and in September, after further schnorkel training, met her fate on her fifth attempt to gain the Atlantic. As far as can be judged from the position of her sinking - learnt since the war - she had still been unable to manage her schnorkel and had been bombed and sunk while heading for base.
All non-schnorkel boats, as they became operational, continued to be sent as reinforcements to group Mitte in the Norwegian ports. Because of continuous daylight at this time of year and the consequent added danger from air attack, the six boats hitherto keeping watch off the coast were withdrawn on 16th July when it was revealed that U.319 was missing and that three other boats had suffered bomb damage. After the withdrawal of the anti-invasion guard, group Mitte remained distributed among Norwegian ports, its strength being maintained for a while at 22 boats; but, from the end of July, 14 of these were transferred, at intervals, to Libau and Revel for operations against Russian naval forces in the Gulf of Finland, their place being taken by six schnorkel boats.
The few Type IXC boats to become operational just sufficed to maintain about three on meteorological duty between Greenland and the Azores. The only Type VIIC boat to come into service in July was U.300 which, after a brief spell in the Minch, had to return owing to bomb damage, and it was not until mid-August that a number of medium boats were available for operations. Of these, two were disposed in attack areas off Reykjavik, two north of the Minch, one in the Moray Firth and three in the North Channel, the commencement of their activity being confirmed by several intercepted signals from enemy patrol forces.
The first report received from this batch of U-boats came in on 30th September and was very satisfactory. It originated from U.482, which had operated in the North Channel from 30th August to 10th September and claimed to have sunk one destroyer and four ships totalling 23,000 tons from an ingoing convoy. British records show that she sank the corvette HMS Hurst Castle and four ships aggregating 31,611 tons. On the strength of this report, two more boats from Norway, and five schnorkel boats on their way back from France, were sent to the area, where they were allocated prescribed attack sectors. At the same time, realising that continuous schnorkelling in the face of heavy enemy opposition imposed great strain on the crews - particularly the newcomers - we permitted those Commanding Officers working in inshore waters to decide for themselves whether to withdraw to the westward, or, in case of excessive strain, return to base before expending all their torpedoes.
Subsequent to U.482’s successful sortie, the enemy appeared to cut down on traffic in the North Channel and succeeding boats, which remained there for only a few days, achieved nothing. The same conditions were experienced by U.262, U.714 and U.758, during a brief spell in the Bristol and St George’s Channels, where they surprisingly reported very little traffic; what traffic there was consisted exclusively of convoys and, with slow-moving schnorkel boats operating in tidal waters, much skill was needed to make contact. Nevertheless, losses being slight - one boat west of the North Channel and another west of the Hebrides - we were encouraged to continue with this type of operation and to send schnorkel boats into all British coastal waters.
457. Remote areas, except the US coast
Five days after the commencement of the Normandy invasion, the few boats still operating in remote areas - two south of Nova Scotia, two in the Caribbean and two in the Gulf of Guinea - were instructed to start for home with sufficient fuel to take them, if necessary, to Norway. As it happened, by the time that U.516 and U.539, returning from the Caribbean, had reached Cape Ortegal - in mid-August - the threat from the Allied Biscay blockade had become so serious that they were perforce ordered to proceed to Norway. U.539 needing additional fuel for the trip had subsequently to be supplied by U.858 - a meteorological boat - some 400 miles south-west of Iceland.
U.530 spent a considerable time close to Trinidad, but the routes of the convoys entering and leaving here were so widely dispersed that she failed to get in a single attack. Operations off the Brazilian coast finally ceased when U.861 left the area in July. The African coast north of Dakar was evacuated for good on the return of U.546 in August, and the return of U.170, late in September, marked the end of operations off Freetown. Two of the last Type IXC schnorkel boats to sail from the Biscay bases went to the St Lawrence, in which area, patrolled mainly by aircraft, the Commanding Officers felt confident of success; but neither of them had the good fortune to discover a convoy and they achieved nothing. Operations in the Indian Ocean, however, continued satisfactorily, using about three Penang-based boats at a time, and in August, U.198, U.859 and U.862 encountered considerable traffic around the Mozambique Channel and to the north of Madagascar, where they sank eight ships.
During the period under review, few of the Type IXD boats sent from Germany to the Indian Ocean reached Penang, U.860 being lost in the South Atlantic in June, U.198 to the north of Madagascar in August and U.871 and U.863 in the North and South Atlantic, respectively, in September. U.859 was torpedoed and sunk by an Allied submarine while entering Penang after an operational cruise lasting nearly six months, and at about the same time the torpedo-transport U-boat, U.1062, returning to Germany from Penang with a cargo of vital war materials, was sunk just north of the Equator.
The further loss at the end of May of the Penang-bound U.450 - the last available U-tanker - and of the Type IXC boats U.505 and U.549, was attributed to enemy carrier groups patrolling from the west of the Azores to the Equator. However, we never knew that U.549, before her destruction, had sunk the (to us) notorious American aircraft carrier Block Island and damaged a destroyer. Neither did we know of the capture of U.505, owing to the excellence of Allied security and to the strict isolation of her crew by the Americans. It was not until the end of 1944, or the beginning of 1945, that a U-boat officer held in a Canadian prisoner-of-war camp managed to pass us a message warning of the probable capture of a U-boat, intact and complete with signal publications.60 We were thus provided with a possible explanation of many curious incidents which had occurred in the Atlantic since the summer of 1944, when enemy forces had contrived to turn up at our prearranged rendezvous with the same punctuality as the U-boats themselves.
52 U.740 and U.821 were sunk by aircraft on 9th and 10th June respectively.
53 No ship was sunk in this attack, nor was H90 - HMS Broadway - present.
54 British records show that both were sunk in the Channel.
55 Bold was the asdic decoy.
56 The cruiser HMS Frobisher was slightly damaged by a/c bomb on 18th July and the frigate HMCS Mantane on 20th July.
57 A highly contentious view, which both greatly over-estimates the capability of the RAF at that time and underrates the efficacy of the German defences.
58 British records show one corvette, one LCI(L) and one steamship of 7,176 tons sunk and one LST damaged.
59 By “circular saws” he probably alludes to Foxer. Reference to sonic buoys is not understood.
60 U.505 was captured on 4th June 1944 by USS Guadalcanal, USS Chatelain, USS Pillsbury and USS Jenks, and successfully brought into Bermuda. Many valuable documents were taken intact.