The German proximity fuse.

In message
, Geoffrey
Sinclair writes
It should be noted the claimed major shoot down was the USN
ships reporting what they thought they had shot down.

And, like bomber gunners, both raid count and bandits splashed were
prone to error... when Seaman Smith sees the aircraft he's hammering
with 40mm shellfire burst into flames and ditch, naturally that's *his*
kill. As it is also Seaman Jones who'd just riddled it with 20mm, and
it's also a kill claimed by the 5" teams who had been shredding it with
fragments on its way in... and every one of those claims is honestly
made.

In the fights with Kamikazes the USN ships reported they needed
to fire 100% VT (proximity) fuses, since there was normally no time
to set and use time fuses.

However, they were told by BuOrd to use 25% time fuzed shells: the
bursts had deterrent effect, indicated the raid to other units, but
primarily it pointed up any gross errors like the director aiming at the
wrong group of aircraft.

Before the RAF introduced window Bomber Command was recording
that around 6 to 9% of returning aircraft on night missions had flak
damage, March to July 1943. This dropped to 2.85% in August and
averaged 2.3% for all of 1944 and 1.4% for 1945. Window remained
effective against the fire control radars for the remainder of the war.
The average for aircraft returning damaged by flak on night raids
February to December 1942 was 6.5%, for all of 1943 5.8%. In effect
a proximity fuse at around 3 to 7 times the lethality would restore to
exceed the pre window hit rates.

US experience was that VT fuzing was about three times more effective
than time fuzing on a straight rounds-per-bird comparison: this rose to
nearer four times by war's end as experience was gained and reliability
improved.

--
He thinks too much: such men are dangerous.
Julius Caesar I:2

Paul J. Adam MainBoxatjrwlynch[dot]demon{dot}co(.)uk