In 1984 Iowa conducted a comparison of optically determined ranges from the Spot One (Top Spot) 26.5 foot range finder and radar determined ranges from the Mk13 fire control radar located on top of Spot One.... At 44,000 yards the compared ranges differed by 100 yards...
Bill Jurens wrote:That relative performance of optical vs radar spotting, though the quotes are probably correct (Cdr Morss does not make things up), would certainly be considered atypical for regular day-to-day performance. Even in the 1980s the Iowas habitually used radar spotting for range, optical spotting for deflection. The navy very carefully compared the relative accuracy of optical vs radar, vs aircraft spotting during 1944-45, finding that at least for range, radar showed considerable superiority. It's important to discriminate, however, between establishing range as an absolute value, and spotting the M.P.I. which are really two different things.
Brad Fischer wrote:Finally with regards to shock to radar systems it was a problem but was, relatively speaking, fairly rare. We did a survey of all the action reports and gunnery exercises for Mark 8 equipped battleships during the war and the average failure rate was 4.7% for a single unit and a 0.22% failure rate for a two unit failure. This data was compiled from 300 firing events.
Francis Marliere wrote:Mr Fischer, is the data for Mk8 representative of WWII radars or can we expect the earlier sets to be less reliable ?
Thorsten Wahl wrote:x axis time starting with 0 to 30 minutes
upper graph measured distance
-black true distance measured by Langbasisgerät
-green 10 rangfinder Vormars
-orange 10 m rangfinder aft
-yellow 10 m rangfinder turret A
-blue 10 m rangfinder rangfinder turret B
-dashed line average from the rangefinders
lower graph rate of change of distance
-black true rate of change
-red rate of change from the E Mittler
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