Partial translation of document C-21

              INTENSIFICATION OF U-BOAT WARFARE
                   [Extracts from a file]

(Page 1)
Conference with Head of Naval War Staff: 1.1.40.
Special Points.

1. Report by Ia [Chief of staff] on Directive of Armed Force
High Command of 30.12. According to this, the Fuehrer, on report of C.
in C. Navy, has decided:

(a) “Greek merchant vessels are to be treated as enemy vessels in the
zone blockaded by U.S.A. and Britain.

(b) In the Bristol Channel, all ships may be attacked without warning.
For external consumption these attacks should be given out as hits by
mines.

Both measures are to be taken with immediate effect”

[Pencil note:] “For the conduct of the air war too? See page 5 above”

(Page 5)

Conference with Head of Naval War Staff: 2.1.40.
Special Points.

1. Report by Ia on Directive of Armed Forces High Command, dated 30.12.,
referring to intensified measures in naval and air warfare in connection
with “Fall Gelb” [case yellow, the code word for the invasion of Holland
and Belgium].

In consequence of this Directive, the Navy will authorize,
simultaneously with the general intensification of the war, the sinking
by U-boats, without any warning, of all ships in those waters near the
enemy coasts in which mines can be employed. In this case, for external
consumption, pretense should be made that mines are being used. The
behaviour of, and use of weapons by, U-boats should be adapted to this
purpose.

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(Page 37)

U-boats Warfare against Merchantmen : 6.1.40.

The Fuehrer has in principle agreed (see minutes of report of C. in C.
Navy of 30.12) to authorize firing without warning whilst maintaining
the pretense of mine hits in certain parts of the American blockaded
zone. In accordance with this, the following order is herewith given to
the Flag Officer Submarines, Group East and Group West:

"All U-boats in the North Sea, position between 61 degrees and 56
degrees North and 4 degrees West and 0 degrees, are authorized to make
immediately unrestricted use of weapons against all ships. Attacks
should be unobserved so that the pretense of mine hits can be
maintained".

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(Page 139)
18.1.40
Special Points:

1. The High Command of the Armed Forces has issued the fol-

                                                              [Page 827]

lowing Directive dated 17.1 cancelling the previous order concerning
intensified measures of warfare against merchantmen: The Navy will
authorize, with immediate effect, the sinking without warning by U-Boats
of all ships in those waters near the enemy coasts in which the use of
mines can be pretended.

U-Boats must adapt their behaviour and employment of weapons to the
pretense, which is to be maintained in these cases, that the hits were
caused by mines. Ships of the U.S.A., Italy, Japan and Russia are
exempted from these attacks.

["Spain” has been added underneath in green pencil]

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(Page 221)

Extract from minutes of report of C. in C. Navy to Fuehrer. 26.1.40
[After mentioning the Fuehrer’s decisions on, and agreement with
measures for intensifying U-Boat warfare against merchant shipping the
minutes end with the words:]

Attacks should be unobserved in order to preserve as far as possible the
pretense of hits by mines.