Chapter 10; Attack on the U-Boats

COASTAL COMMAND has, broadly speaking, three methods of dealing with a U-boat once it has left harbour and is on the high seas seeking its prey. It may be discovered by an anti-submarine patrol in the areas where these operate. It is then attacked by the patrolling aircraft and subsequently by others sent, in response to a signal, from the nearest base if it be within range. Such an attack is called a U-boat "strike." The enemy submarine may also be found by aircraft engaged on a sweep or a special search. That is the second method.

The third is used when the U-boat is near a convoy. If sighted it will be attacked by the aircraft detailed to give protection to that convoy. A U-boat at large has therefore to run the gauntlet twice and perhaps three times on the way out and the same number of times on the way back. Moreover, signals sent by an aircraft reporting that it has sighted a submarine are automatically picked up by other aircraft and by vessels of the Royal Navy. Any in the neighbourhood immediately proceed to the attack.

Let us examine the way in which each method is used, beginning with the anti-submarine patrol. This is flown for a fixed number of hours over a certain area. The aircraft engaged upon it sweep the seas in order to cover the area as closely as possible. The extent in distance and time of the patrol is regulated by the state of the weather, the number of hours of daylight and the range of the aircraft. The area to be patrolled is an expanse of sea, and is marked on a chart. The whole essence of the problem is that the navigator must find this area ; having done so he must keep the aircraft within its limits and he must then bring it back to base.

Before taking off the crews are briefed. The briefing is not the elaborate lecture or series of lectures which it may be in the case of an operation by Bomber Command. The navigator already knows the limits of the various patrols laid on from the station. He is told which patrol will be flown. The duration of the patrol is then fixed, but it is not laid down in a hard and fast manner. The number of
times the area can be flown round and over in the conditions prevailing is stated by the Controller, and it is left to the captain to complete these circuits and to carry on for a further period if possible up to what is known as the P.L.E. (Prudent Limit of Endurance).

A margin must always be left to cover possible attacks on U-boats or combats with enemy aircraft. These cause petrol consumption to rise sharply, for the patrolling aircraft may have to increase speed and fly a long way off the course of the patrol.

Then a word is said on the procedure to be followed when attacking a U-boat. What it is and how it is performed must remain a secret. All that can be said is that each movement of it is designed to produce the ideal combination in any form of attack-speed and accuracy. The circumstances in which submarines are to be allowed to pass on their way unmolested are then explained. The great importance of taking photographs of an attack and its aftermath is emphasised.

Such pictures, including any taken of bubbles or patches of oil, may be of very great value to the Intelligence Officers of the Command. The place of an attack is marked by sea-markers, which are flares dropped on the surface of the water. The aircraft will then report the result of the attack.

The gear carried by the crews includes, among other things, charts, pictures of surface vessels, silhouettes and photographs of German and Italian submarines and aircraft, descriptions of suspect vessels, and a list of aerodromes to which the aircraft may be diverted if the weather is too bad over its base to make a landing possible. From this it will be realised that the crews of Coastal Command take much of the Station Intelligence Room with them in their aircraft.

The duration of the patrol is governed by the weather conditions and the endurance of the aircraft. During it a log is kept by the navigator recording everything seen, any incident or alteration of course, and other matters worthy of note.

Back at base the crews are at once interrogated, the questions being based on a standard form. They report what surface craft they have seen, the state of the weather and of the sea. If a U-boat has been sighted and attacked the interrogation is searching and severe.

Crash dive. Will the U-boat submerge before the aircraft can manoeuvre into the best position for attack? Image 1 in a series of 5

Very great care is taken to collect the evidence and then to sift and weigh it. It is recorded in the form of a special questionnaire which in some Groups is supplemented by what is called an " Inquest " Form.

Even with all this care, however, the assessment of the results achieved by an attack on a U-boat is exceedingly difficult. Accuracy is, indeed, almost impossible except on those occasions when survivors are recovered. The attack is so swift -and the results, if any, so prompt that the surface of the sea has closed like a curtain too swiftly for them to be accurately perceived and recorded. This must inevitably be so. Though great patches of oil have stained the sea, though bubbles have formed and burst upon it, the U-boat may not be stricken to death.

It may still be able to limp back to one of the numerous bases at its disposal for a refuge between the North of Norway and the South-West of France. On the other hand, it is equally possible that the opposite may have occurred and that the bombs or depth charges, of which only one explosion and the disturbance of the water caused by it are seen, may have accomplished their purpose and that the U-boat went down on the long slant to destruction, manned by a crew of choked and drowning men.

The cross-over patrol system was established and flown shortly before the war. Its length has gradually been extended both in distance and in time as more powerful aircraft have become available. An examination of the figures for the number of hours flown shows a steady if fluctuating increase over the first twenty-six months of war. The number and length of the patrols are naturally higher in summer, when the hours of daylight are more numerous and the weather conditions more stable. In July 1940, for example, the number of hours flown by our flying boats on patrol was almost trebled.

Though U-boats have frequently been sighted and attacked, the work more often than not is of great monotony. To keep an unblinking and vigilant took-out from the turrets and side windows of a Sunderland or from the blisters of a Catalina flying over what seems an illimitable stretch of sea demands physical and mental endurance of a high order. Sometimes a fishing vessel, British, Spanish, French, Norwegian, Icelandic, is seen ; sometimes a raft, more rarely a periscope with a spume of foam about it. When that is sighted or when the submarine is seen on the surface, the klaxon sounds and the crew get ready for immediate action. Both bombs and depth charges are used to destroy the enemy.

Direct hit. A bomb has burst on the track of an Italian submarine, whose destruction is assured. Image 3 in a series of 5

" A Sunderland attacked an enemy submarine in a position 285' Cape Finisterre 210 miles. Bombs were dropped within twenty feet when the submarine was at periscope depth and a large oil patch with air bubbles was observed. Later more bubbles appeared in the centre of the patch. After twenty minutes the oil patch extended with bubbles continuing to rise. The aircraft remained in the vicinity for three and a half hours." . . . " Two 100-lb. high explosive tombs were dropped which fell a few yards from the periscope. It is considered that the submarine was hit.

Two large brown patches and a pale blue patch appeared on the surface about seven minutes afterwards." . . . " One Sunderland reported attacking an enemy submarine U.26 in a position 240' Bishop's Rock 204 miles, forcing the enemy submarine to the surface. . . . Bombs were dropped, one of which obtained a direct hit A the stern, causing the submarine to sink. Forty-one survivors were being picked up by a naval unit when the aircraft left." . . . " A Lerwick on convoy escort attacked an enemy submarine and claims a direct hit on the conning-tower. Oil and air bubbles were seen after the attack."

The following attack ended in an event at present unique in this war. On 27th August, 1941, a Hudson patrolling from Iceland sighted " the swirl and wake of a U-boat " about 800 yards ahead. It was then a little after 6.30 a.m. "No actual part of the U-boat was seen," reported the captain, " and vision was very limited owing to rain-squall. Marked position with smoke floats . . . and made a submarine sighting report to base." The Hudson cruised round for a little less than an hour, when it again s ighted the submarine, this time on the surface a mile away on the port bow.

It attacked, but its depth-charges hung up and the submarine dived. A second sighting report was sent. Three hours passed and then another Hudson from the same squadron appeared, having been sent out on " strike." The submarine -it was U-boat 570- had by this time surfaced again and was seen at once 1,200 yards away to port.

The second Hudson dived upon it and released its depth charges just as the U-boat was starting to submerge. " The U-boat was completely enveloped by the explosions and shortly afterwards submerged completely." Two minutes later it shot to the surface, where it remained while " ten or twelve of its crew wearing yellow life-jackets appeared on the conning-tower and came down on deck." The Hudson dived and fired all its guns in turn when each co uld be brought to bear as it swept in tight turns round the submarine. " The U-boat crew at once scrambled into the conning tower and went below." Seven minutes later 11 a white flag was seen to be waved . . . the crew also brought out what appeared to be a white board and held this up on the deck." The white flag was subsequently found to be the captain's shirt. It was lightly starched and had frills down the front.

The Hudson at once reported to base and asked for surface craft to be sent to take off the crew who had surrendered to it. While awaiting the arrival of a relieving aircraft the Hudson kept the U-boat covered with its guns. Throughout the rest of the day Hudsons and Catalinas took turns in guarding the prize, being over it for about eleven hours and a half. Dusk began to fall and no vessel had yet arrived.

" If it appears surface craft unable to reach position before dark," said an order issued at sunset, " after giving due warning you should sink U-boat." It was found possible, however, to arrange for aircraft to remain in relays over the Submarine all night and to keep it in view by dropping flares. Its crew were to be ordered to remain on deck and to show a light throughout the hours of darkness under penalty of destruction if they did not comply. Before this order could be executed a naval trawler arrived in the gathered dusk and sought in heavy seas to take the U-boat in tow. At dawn a destroyer came up and the submarine was eventually brought safely to Iceland escorted all the way by aircraft.

The reason why the U-boat surrendered and the motives of her crew in so doing are not without interest. When she was hit, a rush of water into the hull began to generate chlorine gas. The engine-room crew immediately rushed on deck and refused to go back to their stations. They huddled round the conning-tower and remained there all day and all the following night. It would seem that none of the men had ever before been on an operational sortie.

This captured submarine was almost certainly one of a large concentration discovered in Icelandic waters on 26th August, 1941. To attack them every serviceable aircraft of Coastal Command based in Iceland and the North of Scotland was dispatched in a series of sweeps maintained from first to last light. On 26th August 50 sorties were made, on 27th 34, on 28th 84, and on 29th 56, a total of 224 in four days. Many attacks were made. One, carried out by a Catalina, well illustrates the fortunes of war.

Its pilot saw a U-boat on the surface. He dived towards it, but hardly had he put the nose down when he saw another also on the surface but closer at hand. He diverted his attack to this second U-boat, and as he was delivering it, came under machine-gun fire from his original quarry. He carried on, got into a good position, but when he pressed the button his bombs hung up. Both submarines submerged. On landing at base it was found that the Catalina had been hit by one bullet only. It had severed the electrical connections of the bomb-release gear.

This was but an incident in four days of intensive and successful attacks. The shoal of U-boats was harassed and deprived of all offensive power. Its known losses were considerable, its suspected high. The operations against it showed what Coastal Command can achieve in an area within range of its aircraft by a series of well planned and organised sweeps.