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Curious object n°1.
- Thread starter JulienCD68
- Start date
Maybe not the same as but not too dissimilar to the fuze for the 8 Inch nuclear spotting shell. https://www.bocn.co.uk/threads/us-fuze-t316.106696/#post-331475 . See also https://www.bocn.co.uk/threads/nuclear-projectiles.85947/ re the M424 8 Inch nuclear spotting shell.
JulienCD68
Well-Known Member
Thank you.
Do you have any additional information?
Any documentation that could help us?
Do you have any additional information?
Any documentation that could help us?
Try here:
Canada's Naval History
Learn more about Canada's naval history since 1910 through hundreds of objects and images drawn from the collections of the Canadian War Museum and its partners. Most are available on-line here for the first time, and each provides a unique glimpse into the past.
www.warmuseum.ca
JulienCD68
Well-Known Member
Thanks for all.
Berst regards.
Berst regards.
JulienCD68
Well-Known Member
JulienCD68
Well-Known Member
These devices are very similar in design wether they're from 1920 or 1950, and regardless of country of origin (my initail thought was German post-WW2, but that's just guessing based on the material used and the shape of the pendolum).
We (RNoN) used pre-WW2 british D/R-recorders in the german Type 1215 exerciseheads for the G7a(TI) torpedoes up to them being phased out in 2000 (mounted in the pocket for the tracking-lamp with an adapterplate).
We have a few recorders at Herdla torpedobattery (ref attached photo).
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JulienCD68
Well-Known Member
Interesting.
Thank you very much.
Thank you very much.
AR & AV Should mean Arriere and Avant. French probably
JulienCD68
Well-Known Member
It's a mechanical depth- and roll recorder. It's located in the exersicehead to record the behaviour of the torpedo in regards to roll and depthkeeping (ie effects on vertical/horosintal rudders). The movements are detected by pendolums controlling a pen or a needle writing/scribing the movements on a roll of paper that is transferred from one roll to another controlled by a mechanical mechanism run by a spring which is wound up before the unit is installed in the head. The waterflap on top flips back from the waterpressure, unlocking the spring and pendolums, so that the drive starts moving the paper and record the torpedo's movements.
The attached images are scans from 1972 with Mk VIII exersice torpedoes at Kaholmen torpedobattery (Oscarsborg fortress). It's not the original papers from the recorders, but traces of them on ordinary paper made with a pen. However, it shows what such recordings look like with the running distance at the x-axis (m), the depth (m) on top, and roll (degrees at the in the y-axses.
Different navies might use different terms, but in my opinion you have the following categories of torpedoes:
* Dummy (torpedo with an "empty" head, or even a model, which replicate a torpedo in terms of phyisical dimensions/weight for various use like testing and certification of loading/launch equpiment etc.)
* Exersice (an ordinary torpedo with an exersicehead, which is used to conduct exersices in regards to launching/steering and verifying all functions of the torpedo. The head can be equipped with various types of instrumention for recording relevant data to be analyzed after the run).
* War (a torpedo with warhead for use in actual combat)
Instruments in the exersicehead might be recording (mechanical/electromechanical/digital) and/or transmitting depending on the type/era, but the D/R-recorders shown here are typically devices from around 1900 and forwards, with only mechanical registration as described above.
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JulienCD68
Well-Known Member
Thank you very much for these clarifications.
Thank you so much, Natter! It reminds me a bit of the old limnigraph that my father kept (from back when they switched to modern models) from his days measuring river flow rates... Modern versions would transmit the data, but with the older ones, you’d have to retrieve the torpedo, right?
Allthough today it's technically feasible to transmit telemetry during the run, I honestly can't see the practical need (maybe in some special occasions during development-procedues to see live respons from steering commands?). Obviously all torpedoes are retrived so the data would be recovered regardless format (mechanical recordings on paper, electronic recordings on magnet tape, digital memory etc). It's a reason these old mechanical D/R-recoders were in use for close to a century: They fulfilled the purpose/need as they were.
I forgot to comment that these recordings show both a normal run (low depth-setting, using the magnetic infleunce mechanism of the CCR pistol) as well as one with an initial unstable depth (obviously a torpedo with the influence-mechanism disabled). It's also worth mentioning that this battery has an almost uniqe sub-surface launch-system where the torpedoes are launched from a frame lowered into the water to a depth at about 3 m. With an ordinary torpedotube launching the torpedo with a powdercharge or pressurized air from a few meteres above the water, the torpedo will normally seek even deeper initially (at our other batteries with the ex-german G7a(TI) torpedoes we typically saw an intial depth at 30 m).