"ملف 28/1 J تخريب آبار النفط، إلخ" [و‎‎١‎١] (٢٦/٢١)

( V 9772/20/49 )
Enclosure.
ANTI-SABOTAGE PRECAUTIONS.
Addendum to Memorandum dated January i t 1940.
(M.O. 1767/39).
Possible Methods of Sabotage.
1. Investigation of two recent cases of sabotage of
British merchant ships in foreign ports has revealed the
following facts. In each case an explosive charge
fitted with a delay action fuse was probably concealed in
a package, part of a consignment of similar packages Kttk
which formed part of the ship^ cargo. These were a
container of strawbex'ry pulp and a case of canned beef.
The loading ports were a Bulgarian port and Buenos Aires
respectively.
2. Information has been received that bombs or
incendiary devices may be concealed in the following
objects which, although not part of the ship’s cargo,
may be placed on board by enemy agents in the hope that
they may be overlooked:-
Tea canteens, thermos flasks, water bottles,
jam jars and similar articles, containing explosives set
off by delay action fuse.
Packing cases, specially treated to make them
inflammable and liable to spontaneous combustion.
Portmanteaux or trunks delivered on board
immediately before sailing and purporting to belong to a
passenger or member of the crew.
Clothes, rags or dunnage, pretreated to render
them inflammable and ignited by an acid capsule secreted
among them. These clothes, &c., have a dusty or greyish
appearance owing to the chemical treatment.
Lactometers, fountain pens and coloured pencils
may be small incendiary bombs with delay action.
Imitation lumps of coal, briquettes, &c.,
containing xx explosives.
Lead objects in the shape of a cigar containing
an incendiary liquid and a delay action fuse.
Lubricating oil to which a substance has been added
which will cause the oil to catch fire when the engines are
xtxx started.
It will be appreciated that no list of this nature
can fee. possibly be exhaustive, and therefore objects which
do not appear on the list are not for that reason to be
regarded as free from suspicion.
Bombs have been discovered which consist of two
cartons of cardboard, 4-£-in. by 2£-in. containing sulphur
and Jjotassftun nitrate. These charges are ignited by
means of a percussion cap operated by a small watch which
has a maximum delay of one hour, rhese are contained in a
brass cylinder which may be inserted in one end of the carton
or between two cartons.
Only by exercising the strictest vigilance can such
attempts at sabotage be prevented.