SUCCESSFUL USE OF FLARES BY COASTAL COMMAND AIRCRAFT ATTACKING AT NIGHT To defeat the cautious tactics of the U-Boats, which now surface for only a few hours during darkness, aircraft of Coastal Command not fitted with Leigh Lights have been supplied with flares. They are of two million candle-power and burn for 50 or 60 seconds. Released from a height of about 700 ft. when the aircraft is some 3,000 yards from its target on its A.S.V. run-in, they will give, in clear weather, a sighting range of about 1,700 yards and in haze about 800 yards. Five attacks by aircraft using these flares in the Bay area have recently been assessed. Unfortunately, although the attacks were well carried out, it was difficult to obtain evidence of damage. At 2305 on 5th January, 1944, Halifax aircraft R/58, on anti-submarine patrol, obtained an A.S.V. contact. It had already made several contacts with trawlers but on closing this contact it sighted a wake about 4 miles distant. Visibility up moon was about 5 miles and down moon about 2 miles, but there was a slight haze and the aircraft could not see the U-Boat itself until the range was about 3,000 yards ; three flares were then released. The U-Boat first tried to shoot them out hut turned its guns on the aircraft as it came in to attack. After dropping six charges from 150 ft. the aircraft climbed to 800 ft. and, circling the U-Boat, which had remained on the surface, released another flare when about four points abaft the starboard beam. The U-Boat again tried to shoot it out. The aircraft then attacked with gunfire and the U-Boat dived, apparently within about five minutes of the depth-charge attack. The next attack in which flares were used was made by Halifax aircraft S/502 at 0403 on 29th January. Visibility was bad, being not more than mile. After making one blind attack on an A.S.V. contact, the aircraft obtained a second A.S.V. contact bearing Red 80°, range 6 miles. It homed on to it on a course of 090° and at a range of 2 miles by Radar the stop watch was started and run for 24 seconds. Two flares were then released, at an estimated range of 2,000 yards. The Radar operator continued to home the Captain and at 300 yards range a surfaced U-Boat was sighted dead ahead. Using the Mark XIV bombsight, the aircraft dropped two 600 lb. A/S bombs from a height of 1,300 ft. They were released when the conning-tower of the U-Boat, illuminated by the flares, was seen on the graticule of the bombsight. It was estimated that the bombs straddled forward of the conning-tower ; they were felt to explode and immediately afterwards the U-Boat's flak ceased. The aircraft crossed the position a second time and then had to set course for base. On the same day another Halifax, " U " of 502 Squadron, was flying in the Bay on anti-submarine patrol. Visibility was described as " very dark under cloud (6/10 to 7/10 base 400-500 ft.) nil without illumination." An A.S.V. contact was made at 2107. At first it was thought to be with a passing aircraft but during the investigation of the contact a single red pyrotechnic, apparently fired from sea level, was seen on the aircraft's port quarter. The Halifax, maintaining contact with difficulty, released six flares at about 2 miles range at a height of 800 ft. and then sighted a fully surfaced U-Boat 11 miles away on the port bow. In this case the flares were particularly valuable, as the aircraft could not make a direct attack ; they enabled it to keep the U-Boat in constant view while circling to get into position. The circuit was almost completed when the U-Boat was seen to be taking evasive action to port ; the aircraft therefore made a steep turn to port, dropping two more flares just before levelling out for the final run. Coming in at Green 160° to the U-Boat's course, the aircraft dropped four 600 lb. A/S bombs from a height of 400 ft. The rear gunner saw explosion plumes on either side of the U-Boat and also had a momentary view of the conning-tower before it was obscured by spray. It was estimated that three explosions were to starboard and one to port of the U-Boat. The aircraft circled the area but it could not find the U-Boat again. Aircraft " L " of the same squadron carried out the fourth attack a few hours later, visibility being again described as " nil." Homing on a radar contact made at 5 miles range, the aircraft released, from a height of 1,500 ft., three flares which revealed a surfaced U-Boat dead ahead. The U-Boat at once opened fire. Using the Mark XIV bombsight, the Halifax dropped three 600 lb. A1S bombs from a height of 1,100 ft. They seem to have been dropped with extreme accuracy ; the flak ceased at once and very soon afterwards contact was lost. At 2202 on 18th February Halifax L/58 made what is regarded as a model attack. Flying at 2,000 ft. it obtained radar contact almost dead ahead at a range of about 12 miles. Homing was accurate and good contact was maintained up to the time of the attack. When the range was 3,000 yards four flares were released, the height of the aircraft then being 750 ft. Almost immediately afterwards a U-Boat was sighted bearing green 5° distant 1 miles. It was making 18 knots on a course of 090°, the aircraft's course being 173°. Flying at a height of 100 ft. it came in fine on the U-Boat's port bow to make its attack with six depth-charges spaced 100 ft. apart. They were seen to straddle the track of the U-Boat just ahead of the conning-tower, the third charge being close to the U-Boat's port side. The conning-tower could be seen disappearing into the depth-charge plumes. Unfortunately this very promising attack produced no evidence of damage, though the aircraft searched for two hours. It is unfortunate that so little evidence was available for the assessment of these attacks. whatever damage the U-Boats sustained, their crews must have been unpleasantly surprised and shaken by this form of attack. Without the use of flares, the attacks could never have been made at all—on three occasions visibility was nil. It will be noted that two of the attacks made on these particularly dark nights were carried out at considerable heights, one at 1,300 ft. and the other 1,500 ft., thereby giving the aircraft some measure of protection against the enemy's fire. The attack by Halifax L/502 was particularly good, in that it had to manoeuvre into its attacking position after the flares had been dropped owing to the U-Boat taking evasive action. Source - The Anti-U-boat Division of the Naval Staff. 15 March 1944.