Luftwaffe losses to ground fire during Bodenplatte

[Jaap Woortman]

Maybe that this page can be a contribution to your discussion. It is a page from Ralph B.Baldwins book :"The deadly fuze". It tells the story of the development and use of the proximity fuze at allied and German side.

Jaap

[ArtieBob]

IIRC, the U.S.Navy quad 40 mounts still had ring and bead sights (for manual pointing and training). However, the Mk 56 fire control system that I remember had gyro lead computing , but was remote from the mount, electrically linked. The cable bringing in the signal to the mount could take a total of 720 degrees twist (360 each way, before having to be manually untwisted). The electodyne drives were very fast in slew and first loaders needed to be well braced as we could get flung off the mount if we were not careful. I have no idea if the Mk 56 was in service during WWII, but the ship I was on in during the 1950s appeared to be pretty much in WWII trim except for the 20mm mounts having been torched off. You are absolutely correct that there was not much reason to upgrade the 40mm after WW II. The 3"/50 mount I mentioned was not the manually loaded WW II version, but the semi-automatic twin mount that was designed to be a drop-on replacement for the quad 40s. This was a direct reslult of the kamikaze attacks and the need not just to "kill" the attacker, but literally have enogh blast and kinetic effect to knock them out of the sky. I believe they were barely too late for WWII.
Next comment, I remember watching the bursts around the towed sleeves, since I was second loader on the 5"/38, I would not have been able to see what was going on during AA practice (gun house). And since I was seeing bursts, if they were 40mm, it would seem that they would be from VT, since I do not remember the 40mm having a mechanism for setting fuzes. But, as I said, my memory could be getting fuzzy after more than 50 years.
Final comment, VT fuzes were apparently restricted to naval use for most of the war, primarily so there was little possibility that unexploded fuzes could be recovered and copied by the enemy (a la H2S).

Best Regards,

Artie Bob

[George Hopp]

Thank you for that, Artie. Very interesting indeed.

As you say, the VT fuzes were used primarily by the Navy through most of the war, to ensure that duds could not be retrieved by the enemy. As a result of this policy, the VT fuzes intended for use in various Army howitzers, were not able to be used and so thousands of them were stockpiled. But, in December 1944, after it was learned that the German drive had captured a munitions dump that had shells fitted with VT fuzes, they were released for general use.

I had supposed that there would be some criticism of my mentioning the use of wet batteries to power the fuze. The earlier fuzes had dry batteries, but their shelf life was only 2-3 months, and this was considered totally unacceptable. So, they created a wet battery, but with the active electrolyte in a glass ampoule (small bulbous glass vessel hermetically sealed) that broke as the shell was fired and permitted the electrolyte to be distributed over the battery plates.

As a byproduct of the low-level Kamikazi attacks, since the reflections from waves could set off the fuses prematurely, a new circuit was devised to reduce the sensitivity of the fuze to the spurious wave noises. And, there were many other problems that the Navy had to overcome to get the fuzes to work properly; but they did, and the fuzes, based on Navy action reports, apparently multiplied the effectiveness of the AA guns by a factor of 3.

All the best,
George

[Graham Boak]

My understanding is that the VT fuses were used against the V1, rather than being restricted to Naval use. The dominant guns there were the 3.7in. and the 40mm Bofors. Initially this was restricted to the UK mainland but later there was considerable effort placed into the defence of Antwerp.

English Heritage was to issue a book on the Diver AA campaign to go with their excellent work on AA Command, but I've yet to see it appear. The matter of fuses will doubtless be discussed, but I suspect that the comments above are correct and the 40mm shell was just too small at this stage.

[George Hopp]

You're right of course, Graham. What I should have said was that while the majority of VT fuze usage was by the US and Royal Navies, it was also used in AA guns in the UK and other Allied territories. Until Dec 44, these fuzes couldn't be used for artillery fire which could yield the enemy a fuze in a dud shell (this injunction also included shore bombardment by naval guns). While the US Navy was creating VT fuses for the US forces, it was also making them for the British forces, including fuzes for the principal Royal Navy AA guns, for the British Army 3.7" AA gun, as well as for Army guns and howitzers.