Good afternoon,
sorry if I follow up with this old thread too, but the Turkish blueprint posted by Bonnex dated 18 August 1941 sounds to me like a further confirm that this fuze is German and was issued to ABWEHR agents, the which sabotage section in Turkey (ref. II K.O. Naher Osten or KONO) was established during the summer of 1941 in order to bridge operations to the Middle East.
One of the most common shortage of material for the personnel operating abroad were fuzes fitted with clockworks as delay mean and mechanical activation, it looks in my opinion that this “Mark I” fuze was designed in order to overcome this problem by releasing a simple device, manufacturable abroad with light machines by sourcing local materials.
It is in fact as simple in principle as a normal watch used to close an electrical circuit, it relies on a standard 12 hours movement with a slotted wheel spliced to the hours pivot and a lever system composed of few pieces to release the striker. Notice the movement is neither drawn in the Turkish blueprint or in Allied documentation, this might mean from the producer side that any 12hrs watch movement could do the job and from the Allied side that among the samples recovered, they found different commercial movements.
Moreover from the pictures of the samples recovered it is clear that there was more than one manufacture involved, just look at the samples of page 5 and 6 of Bonnex’s “Mk 1 Timer Part 1”, these are made in different workshops with different materials (notice for instance the movement cover in plastic or brass and the differences of the slotted wheel).
The same slotted wheel principle is also seen in the later Mark IV, firstly recovered in the United States during June 1942 after the landing of ABWEHR agents delivered by submarines. The Mark IV is pretty much a Mark I, reshaped and with a reduction gearbox to extend the delay time up to 14 days; It also relied on a commercial 13 jewel Swiss movement designed for a wrist watch, 20 samples of this fuze were recovered with serial numbers following the pattern K 1XX, the meaning of the designation K 1 is not known to me.
Altough the Mark I has a s/n in numbers that follows a different pattern, in my opinion comes from the same office that designed the Mark IV.
It is interesting to note that in a memorandum about the ABWEHR agents landed in the US, the 14 days clockwork is described as being (brackets are mine):
“..based on the mechanical striker principle as in the earlier type (ie Mark I)..
presumably the technical deficiencies experienced with the standard 21 day clockwork electric delay mechanism (ie Mark II).. ..
have resulted in this new type (ie Mark IV)
being designed..”.
In this concise historical recap of the ABWEHR material there is none mention to the 7 days clockwork Mk-III, that was likely recovered sometime between April and June of 1942; this might mean that the Mark III (hence the Mark VI) are devices made by a different agency (see:
http://www.bocn.co.uk/vbforum/threa...Sabotage-Delay?p=310623&viewfull=1#post310623).
The later Mark V is an ABWEHR device too, that coincidentally also relies on a third party clockwork taken from the LZtZ 17 fuze which gave delays between 2 and 72 hours; although I have none information about the Mark II clockwork, it seems that among the six marks the only clockworks specifically designed to accomplish the operational requirement without involving third parties movements were the Mark III and VI.
I’m very sorry for the length of this post.
