B-17 CC Additional Material by Robert M Stitt

Coastal Command
Tactical Instruction No. 41
Coastal Command Anti-Submarine Tactical Instruction
C.C.T.I. No. 41
INTRODUCTION.
This Anti-Submarine Tactical Instruction is issued with the primary object of enabling aircraft to destroy U/Boats. All other
results from attacks, such as killing members of the crew, superficial damage by machine-gun fire or forcing the U/Boat to
dive, are of secondary importance.
A number of separate instructions on Anti-Submarine Tactics has been issued by this Headquarters from time to time
and numerous amendments added. These instructions have been revised and consolidated into one, which cancels all
Coastal Command Tactical Instructions previously issued on this subject i.e. Nos. 31, 33, 35, 36 and 40. In future, variations
in tactical procedure will be issued as amendments or addenda. Amplification of the instructions contained herein
will be found in Coastal Command Tactical Memoranda.
To kill U/Boats, crews must have a sound theoretical knowledge of:-
(i) The best means of sighting U/Boats.
(ii) The correct method of attack.
(iii) The correct procedure after attack.
The successful application of this theoretical knowledge is dependent on continual practice. But neither theoretical perfection
or practical proficiency will be of any avail if, when the critical moment comes in a real attack, the release mechanism
for some reason or other fails to function correctly. All Junior Commanders and Captains of aircraft should, therefore,
continually bear in mind:-
(i) The vital importance of air crews being given continual training in delivering attacks.
(ii) The absolute necessity for eliminating any possibility of failures due either to defective maintenance or faulty crew
drill.
VISUAL LOOKOUT.
Good visual lookout by day and night is of outstanding importance in all A/S operations. In order to bring their crews to
maximum efficiency, captains of aircraft must carefully organise a watch system and train individual members in both how
and where to look.
There must always be at least two A/S lookouts who must keep a constant watch while on duty. They should cover a 180°
sector, i.e. from ahead to 90° on either side of the aircraft and one of them must invariably be provided with binoculars.
Lookouts should be changed every half hour whenever this is possible.
The area of sea to be searched must be at a sufficient range from the aircraft - dependent on height and visibility - to give
the crew a good chance of sighting the U/Boat before the aircraft is itself observed.
Full details of how an efficient lookout can best be organised and maintained are given in Coastal Command Tactical
Memorandum No.50.
A.S.V. LOOKOUT.
In addition to a visual lookout, it is essential that, subject to the restrictions detailed in para. 10 below, that an efficient
A.S.V. watch should always be kept. The proper use of A.S.V. by day can be expected to increase appreciably the total
number of U/Boats sighted and by night is indispensable.
MK. II A.S.V.
There is no restriction on the use of A.S.V. Mk II by night, but except when specially ordered it is not to be used by day on
A/S patrols unless:-
(i) Visibility is under three miles.
(ii) Aircraft is flying above cloud in sufficient quantity to make sighting of U/Boat unlikely at over three miles. A.S.V.
should be switched off at least 10 minutes before descending through cloud.
(iii) Required for navigational purposes.
When a Mk.II A.S.V. blip fades and the operator is reasonably sure that it was caused by a U/Boat, the following procedure
should be adopted, except (a) at night and (b) on convoy escorts:-
(i) Switch off A.S.V.
(ii) Leave area to a distance of at least 20 miles.
(iii) 20 to 30 minutes after leaving area, return without using A.S.V. at height which will ensure maximum degree of surprise.
(iv) Should no sighting follow, continue duty ordered.
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