627 Squadron in retirement









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Thorpe Camp

At First Sight

At Second Sight

Mosquitos Airborne


BEF Al Faw Video '05


At First Sight
U Boat Pens - Brest - Norman MacKenzie DFC. and Andy Denholm

This is, strictly speaking, an account of a 617 Squadron operation using 12,000lb “Tallboys”, but 617 were on the same station as 627, and we had acquired a propensity for taking pretty pictures of our own operations from a low altitude, for Bomber Command, and were therefore on the spot, so to speak for recording this effort, on film.

As the war against the U-Boats increased steadily at sea, one “Thorn in the Flesh” was the U Boat pens at Brest. They had been attacked on many occasions using different types of bombs, but with minimal success.

Specially designed bombs were manufactured to give the necessary penetration through the reinforced concrete roof of the pens before detonating. These bombs were highly streamlined with extremely robust casings, and if my memory is correct, were designed by the great Bames Wallis. Having confidence that the design of the bomb was right, the next important factor was to ensure that they could be placed accurately on the target!

I am sure that there must have been many squadrons capable of carrying out that duty, but the one chosen was 617, of Dam Buster fame, The raid was planned for 12th August 1944, and on the morning of that day I remember seeing the trolleys being rolled out with covers over the bombs. One, however, was uncovered and it appeared to be very sleek, no doubt to give a very high velocity.

Woodhall Spa was the base for 617 Squadron of Lancasters, and also 627 Squadron of Mosquitoes, the low level night marking specialists, of which I was one of the navigators. My pilot was Norman MacKenzie, “B” Flight Commander, and we were put on the battle order to accompany 617 Squadron for the purpose of shooting some 16 mm film of the delivery of the bombs.

Take off time was 0755 and we flew in one of the Canadian built Mossies with Packard engines, a MkXX, “H” KB215. We preferred the MkIV aircraft with Rolls Royce engines - they had a smoother purr than the Packards and didn’t cut out as the Packards did when going into a dive, due, I believe, to the design of the Stromberg carburettor. Apart from this they were very good aircraft.

Taking off about 45 minutes after the 617 boys we climbed to our normal cruising height of 28,000ft and set course for Brest. During the last fifteen minutes run into the target we reduced height to 16,000ft to come in just under the 617 Lancs to enable us to see the bombs being released. An accurate calculation of the time of impact enabled me to start filming a few seconds before the first bomb exploded. This gave a clear picture of the target showing the results of previous attempts to gain entry. The nets and ships in front of the pen entrances are so located as to discourage a low level attack, probably with torpedoes.

The film, and video with stills of the film, show the accuracy with which these special bombs were dropped, although the clouds of debris prevent the sighting of the striking point of the later bombs. It is interesting to note that the pictures indicate a beam of light projecting from one of the pen entrances. It is possible that this has been created by the flash from a bomb being detonated inside the pens, or a high intensity fire following such an explosion.

The day of the raid was one of brilliant sunshine and I can remember the “greenhouse” effect inside the Mossie cockpit. Over the target there was high level flak, the accuracy of which can be judged by the puffs of smoke shown on the film, and through which we passed. It was one of those occasions when the smell of cordite was quite strong inside the cockpit!

The return flight was uneventful, touching down at 1110hrs.

No. 627 Squadron Battle Order

'H' KB215
S/L MacKenzie. N. W.
P/O Denholm. A.
07.55hrs 11.01hrs Photo Recce. Target U-Boat Pens Brest. Visibility very good. On target from 09.45 to 09.49hrs. About three bomb bursts seen on N.W. corner of aiming point, which was then obscured by smoke

Three stills from the cine film taken by:

F/O Andy Denholm in Mosquito H – KB215, of bombing of Brest U-Boat pens by No. 617 Squadron, using 12,500lbs ‘Tallboy’ bombs. In the first photograph can be seen the ‘Tallboy entering the concrete pens, in the second the bomb exploding and in the third can be seen the flash and debris coming from the mouth of the pen over the waters of the harbour, conclusive proof of penetration.

Copyright 1943-2012 627 Squadron in Retirement or as credited