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SMD-ISRB Sympathetic Fuze

B

Bonnex

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Bellifortis,

The sympathetic fuze you asked about that features in the "NDRC Misc Weapons Report" was a joint ISRB and Admiralty Superintendent of Mines Design (SMD) development although most of the work was done by SMD. It was developed in time for the 'Cockleshell Heroes' raid on the Gironde led by Major Hasler RM.

The fuze was not particularly reliable and Cotterill of ISRB Stn IX designed a click diaphragm fuze with soluble plug delay but owing to pressure of work this fuze was passed to the USA for further development (resulting in their 'Concussion Fuze').

I will add some more detail later.
 
Bonnex said:
Bellifortis,

The sympathetic fuze you asked about that features in the "NDRC Misc Weapons Report" was a joint ISRB and Admiralty Superintendent of Mines Design (SMD) development although most of the work was done by SMD. It was developed in time for the 'Cockleshell Heroes' raid on the Gironde led by Major Hasler RM.

The fuze was not particularly reliable and Cotterill of ISRB Stn IX designed a click diaphragm fuze with soluble plug delay but owing to pressure of work this fuze was passed to the USA for further development (resulting in their 'Concussion Fuze').

I will add some more detail later.
Click to expand...

Herewith a description of the fuze/pistol from an Admiralty document in the public domain (TNA ADM189). There are a couple of minor errors.

ADM189-105.jpgADM189-018.jpgADM189-019.jpgDSCF8006 SMD WITH CAPTION.jpg
 
Hi N.,
thank you for posting the additional info. You mention that the fuze was not particularly reliable. If it was used in Operation Frankton, was there any feedback on its reliability, in that operation ?
regards,
Bellifortis.
 
Bellifortis said:
Hi N.,
thank you for posting the additional info. You mention that the fuze was not particularly reliable. If it was used in Operation Frankton, was there any feedback on its reliability, in that operation ?
regards,
Bellifortis.
Click to expand...

I don't know the answer to that. Clearly the attack teams would not stay around to gather information on the workings of their limpet mines (and of course only one team survived the Operation and its aftermath). The most likely 'feedback' would be from German investigations I would have thought.

Paddy Ashdown's splendid book on the raid (A Brilliant Little Operation, Aurum Press 2012) has a list of results compiled and sent to Berlin the day following the attack. Four ships are identified as having been damaged and the time of explosions given:
Steamer Alabama 5 explosions - 0700, 0703, 0800, 1005 and 1305 hours.
Steamer Tannenfels 2 explosions - 0830 hours and one 30 seconds later.
Steamer Dresden 2 explosions - 0845 and 0855 hours.
Steamer Portland vibrations felt at 0550 and 0630 hours.

It would suggest that none of the Sympathetic Fuzes functioned as intended on these four ships.

[Another two vessels were involved]
 
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