SECRET
From: THE COMMANDER-IN-CHIEF, WESTERN
APPROACHES
Date: 27th April 1943
To: ALL BRITISH
AND CANADIAN ESCORT VESELS OPERATED BY WESTERN
APPROACHES INCLUDING SUPPORT GROUP
Subject: WESTERN APPROACHES TACTICAL POLICY
The enclosed memorandum showing the Tactical Policy in the
Western Approaches Command, is forwarded for information and
guidance.
[signed Max Horton]
A D M I R A L
THE OBJECT
1. The object as laid down in A.C.I's is as follows:
"The safe and timely arrival
of the convoy at its destination is the primary object of
the escort.
Evasion attains the primary object
and should therefore be the first course of action considered.
Although attempted evasion may attain the primary object,
the need for reducing the time spent in dangerous waters and
the desirability of reaching, an area of air cover must be
considered when planning evasive measures."
COMMENT ON THE OBJECT AS STATED ABOVE
2. The object as laid down has been the subject of a good
deal of criticism principally on the grounds that it is not
offensive enough. It has also been suggested that Support
Groups should be given a different object, namely the destruction
of U-Boats. Briefly the arguments of the defensive and offensive
schools of thought run as follows:
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Defensive |
If trade can be maintained
by the continued passage of convoys in comparative safety,
the war can be won by other means. Furthermore, the continued
failure of U-Boats to achieve any great measure of success
will sap their morale and weaken their determination. |
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Offensive |
Failure to destroy the U-boats will enable
their numbers to increase to such an extent that we shall
eventually be overwhelmed by sheer weight of numbers.
The morale of the crews will remain at a high level unless
a reasonable number of casualties are inflicted, and as
a result their offensive spirit will be sustained at a
high pitch. |
SOME FACTORS WHICH AFFECT OUR POLICY
3. The submarine is an exceedingly difficult type of vessel
to locate. It is not therefore possible to search out and
attack him in a large area without very considerable forces
and a very large expenditure of effort. Ho must therefore
be dealt with in those areas where he is bound to concentrate
in fairly large numbers, e.g.: his bases, vicinity of convoys,
areas of approach to his bases, areas in which it is known
by intelligence that he is likely to be present in a reasonable
degree of concentration.
4. The morale of the Merchant Service is showing signs of
strain and it is therefore undesirable to adopt a policy which
accepts the sinking of Merchant Ships as a means of indicating
the presence of a U-boat and thus rendering him open to attack.
5. The U-boat is particularly vulnerable to air attack, against
which at the moment he has no satisfactory counter measure.
His policy for dealing with air attack is at present unformed
and he prefers to avoid contact with aircraft altogether if
he can.
6. The policy of forcing the enemy to dive, which was held
to be the correct one in the past, is no longer always sound.
U-boats are frequently more effectively dealt with when on
the surface, and provided the escort vessel has adequate speed
it is probably preferable to keep the enemy on the surface
as long as possible. Asdics is no longer the only weapon against
the submarine.
7. The enemy's policy for attacking convoys is continually
changing, largely due to the measures we have taken to deal
with his particular methods and due to the introduction of
new equipment. It is essential that we should change our tactics
in order to meet new forms of attack. About a year ago the
enemy was concentrating his effort principally upon surface
attack at night, and at first he achieved considerable success
with this method. The use of snowflakes and R.D.F. has gradually
forced him away from this policy, but it is a fairly safe
assumption that he still prefers this method of attack if
he can carry it out with a reasonable chance of success. This
is one of the reasons why it has been considered undesirable
to abolish the use of snowflakes altogether. The night dispositions
laid down in A.C.I's were largely designed to provide an R.D.F.
screen round the convoy to prevent this surface approach by
the enemy, and operation Raspberry was designed to produce
an effective search for the attacker after he had done his
work.
It is of interest to note, however, that practically every
submarine destroyed during the past year was detected and
dealt with prior to attack and there were very few occasions
on which a successful kill was effected after attack had taken
place. This is probably due to the fact that prior to attack
the submarine is committed to a certain course of action for
the achievement of his purpose, whereas after attack he can
concentrate all his efforts on escape.
8. During recent months there is definite evidence that enemy
policy has undergone a change. The following facts are evident
in this connection:
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(1) All U-boats in contact with the convoy made strenuous
endeavours to get ahead of the convoy. The object of
this appears to be to enable them to attack submerged
if surface attack is deemed to be unlikely to succeed,
or if they are forced to submerge by the action of our
air or surface forces.
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(2) Advantage is taken of the disturbance caused by
the first attack to allow successive U-boats to approach
the convoy undetected. Thus, even if the first attack
is made submerged, or by surfacing inside the screen,
the succeeding attackers may attempt penetration on
the surface.
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(3) Submerged attack or submerged approach is much
more frequently attempted than heretofore.
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(4) U-boats detected approaching
the convoy at night and driven off by the escorts frequently
make no further effort to attack during the remainder
of the night. This may be due to lack of determination
or to the fact that they have lost too much bearing on
the convoy. |
OUR TACTICAL POLICY
9. What should be our tactical policy to meet the existing
enemy policy? To return once more to the object. It is considered
that the object of the close escort must still be the safe
and timely arrival of the convoy. This does not mean that
the object can only be achieved by purely defensive measures,
but it does mean that a reasonable degree of protection must
be afforded to the convoy. It must also be accepted that our
policy must not entail the use of Merchant Vessels as "bait".
The matter is largely a question of numbers. Whatever form
of warfare is considered, the question of the strength of
the opposing forces must play a very large part in deciding
whether an offensive or defensive role can be adopted. In
an extreme case where the number of ships available to escort
the convoy is very small, they must adopt a largely defensive
role, restricting such offensive measures as they may be able
to take to an area around the convoy.
It is proposed to divide the problem up Into two parts (1)
By night and (2) By day.
1. By night
10. It is considered that our policy should be to dispose
a reasonable proportion of our force so as to try and prevent
an attack being carried out on the convoy and to utilise any
balance of our force left over for offensive measures.
11. The question of what constitutes a reasonable proportion
to be so allocated for defensive purposes depends upon circumstances,
but it is generally considered that the number of vessels
so employed should be between six and eight. Under certain
conditions and when the enemy threat is not heavy, such vessels
may be utilised to make sorties against the enemy but they
should not remain long away from the convoy if more than one
submarine is known to be in the vicinity. The disposition
of this force should be such as to provide, so far as is possible,
complete R.D.F. cover with a concentration of force in the
sector in which attack is most probable. This sector may vary
in size but will, with present enemy policy, normally lie
before the beam of the convoy.
12. If the enemy succeeds, in spite of this, in executing
an attack, endeavour should be made to locate and sink the
U-boat that has delivered this attack by carrying out an offensive
search in the area in which he is most likely to be - this
operation should not uncover the convoy to the extent of permitting
other U-boats to approach and attack the convoy unmolested.
13. In this connection, it should be noted that recent reports
show a tendency for U-boats to follow one another in to the
attack from the same direction.
14. The proportion of force available after this close screen
has been provided should be employed to harass and attack
U-boats which are gaining position or waiting to attack on
the outskirts of the convoy. This force should be careful
not to confuse the close screen by approaching the convoy,
unless in pursuit of the enemy.
2. By day
15. It is considered that our policy should be to dispose
a reasonable proportion of our force so as to try and prevent
a submerged attack being carried out on the convoy. The size
of the force so allocated depends on circumstances, but it
is considered that six vessels should normally be sufficient
to provide a reasonable degree of security. These vessels
may be utilised for making sorties against the enemy and in
particular they should do this when the number of U-boats
in contact are few or they are known to be too far aft in
bearing to be able to deliver a submerged attack. One additional
vessel should normally be stationed astern of the convoy to
harry stragglers and generally act as "watchdog".
16. Any vessel over and above the numbers required for providing
the cover referred to above should be used entirely for offensive
purposes such as chasing up H/F D/F bearings or patrolling
at visibility distance from the convoy.
17. If the enemy succeeds in spite of these measures in executing
an attack, endeavour should be made to locate and sink the
U-boat that has delivered this attack, by carrying out an
asdic search in the most likely area where the U-boat maybe.
Vessels not forming part of the close screen may be employed
in such an operation. This operation should not unduly expose
the convoy to attack by further U-boats though this is not
considered to be of such importance by day as it is by night.
CONCLUDING REMARKS
18. The above policy may have to be varied in order to meet
special occasions or peculiar tactics by the enemy. Senior-Officers
of Escort Groups have complete freedom to exercise their initiative
under all circumstances, and it is not desired that they should
be rigidly bound to comply with any of the diagrams or operation
orders laid down in A.C.I's.
It is highly important for Senior Officers of Escort Groups
to retain the initiative and not allow the enemy to throw
the escort force into confusion.
A sharp watch should be maintained for new tactics on the
part of the enemy and an immediate adjustment must be made
in our own tactics to meet any such change, once it is detected.
The air provides a strong offensive weapon which, skilfully
handled, provides an effective counterpart to the somewhat
defensive role that is forced upon the smaller escort groups
when no support group is present. This must be born in mind
by those who feel that we are not being sufficiently offensive.
A new night operation to replace Raspberry and Half Raspberry
is about to be issued for trial. This operation is designed
to conform with our policy as laid down in this paper.
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