http://www.admirals.org.uk/records/adm/ ... 86-259.pdf , P.125 (P.49).
Optical RFs couldn't take enough ranges/minute with sufficient accuracy to build up a good range plot in the time required
Were not the Germans rather more successful in this respect? In part this might have been due their choice of stereo rather than co-incidence type range finders. The former possessed some advantage under certain poor visibility conditions and the longer base length was advantageous.
I do not think the base length had much to do with it.
Better trained German range takers. I think it is safe to conclude that the Germans had better trained range takers than the British.
Method and Procedure of Carrying Out the Trials
The trial lasted about five months, commencing in June, 1922, and finishing in November, 1922. In all, some 700 runs were carried out, representing about 30,000 observations...
4. Rangefinder Operators. - The operators taking part in this trial were the same as in Series I, II, and II, with the exception of P.O. Barrett, who did not participate in Series I. They were:
P.O. Wearn, Qual. RT. I. ..
P.O. Barrett " "
L.S. Webb, R.T. II
L.S. Kibblewhite, RT.II.
Qualified stereo operators of about three years' experience.
From the above mentioned document.
So that represents about 7500 recorded observations for each RF (two stereo, two CI) and this was just one of 4 different trials.
remember that the typical RF at Jutland was either a 3m stereo or a 9ft CI, and neither of these will be useful to generate a range rate at a typical range of say 16000 yds, where even the measured accuracy and consistency of 25 and 30ft stereo and CI RF was insufficient. It is possible that at some unrealistic, close range, an RF might be useable to generate range rates, but not at the ranges that the RN and SMS BCs and BBs were engaging at.
Byron Angel wrote:Range rate data were precisely what the IGN derived from their system of multiple range-finders electro-mechanically feeding a stream of range data via the Mittlungsapparat/Gangmittler devices, whose outputs were then applied to the fire control computation. Post WW1 analysis of the German FC system by USN ONI described it as "rangefinder control". British thinking on the subject in WW1 led them as well in the same direction, but they did not succeed in developing the suitable technology. The key here is that, other things being equal (which they were not), the precision of measurement varies according to the square root of the number of measurements. The German system was capable of producing (and processing) materially more range measurements per unit of time than the British system under action conditions.
Note - According to Brooks, range data from British turret range-finders were transmitted by electro-mechanical typewriter which put the range reading on a counter located in the T/S. The data was then manually taken from the counter and plotted on the table.
Contemporary eyewitness accounts from German Artillery officers states clearly that the Germans were able to generate an accurate range rate at 15.000 + m. under battle conditions based on rangefinder data. And as I stated above this is why that American test doesn’t really tell us anything about the German rangefinder systems capabilities because actual combat experience contradicts the findings of the test.
The above was an RN test.
The problem with combat reports is that the gun is also being used as an RF, through the use of spotting corrections.
The RN tests show us how many accurate ranges/minute might be obtained from an RF; the tests have absolutely nothing to do with integrating that data into a fire control computer, but it is clear that the number of ranges/minute and the accuracy of a 3m RF at ~15000 yds will not allow for an accurate range rate to be developed
Thorsten Wahl wrote:first chart of "E mess Übung gegen vermewssenes Ziel" shows the performance of all optical range keepers compared to the true distance
(black line) own ship<-> target ship during a "Ortungsübung"
the second chart shows how fast changes are detected in the approach speed.
It takes about 1 minute on average to detect a change of course of the target.
Emessung Deutschland shows the individual performance of a sailor (St. Matr, Meier) with different rangekeepers 10 U = 10m RuM
6 U = 6m RuM and so on
average result from 2.II. using 10 m RuM at distances of 23,5 km - 20,0 km
absolute accuracy +38m
relative accuracy 18m
average 29 m
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