Wisconsin Maritime Museum Site Index
Periscope Gallery


The identification plate on back of the periscope. It reads

U.S.N. Bu. of Ships
Submarine Periscope
Design 92KA40T/1.4.H.A
Registry No. 1071
  H.P. L.P.
Magnification 6X 1.5X
Field of View 32°
Small Division
of Reticule Equals
Line of Sight Elev. 74° 30'
Dep. 10°
Inspector S.G.M. Jr.
Mfg. 1943 by
Kollmorgen Optical Corp.
Brooklyn, N.Y.

The design number breaks down as follows:

92 Serial number of the periscope design
K Built by Kollmorgen Optical Corp., Brooklyn, N.Y.
A Type of periscope, a "bifocal altiperiscope". "Bifocal" indicates that the periscope is double power. The "altiperiscope" means that is a periscope which has the combined quality of an altiscope, a type of periscope from which the upper prism has been omitted and thus views straight upward. This means that the periscope can see from the horizon to straight above.
40 Optical length of the periscope in feet
T Treated optics, which allows for increased light transmission and improved definition.
1.4 Outside diameter of the upper part of the reduced head section in inches. Unfortunately, the Submarine Periscope Manual doesn't actually describe what the "reduced head section" is.
HA High angle, permitting view at any angle from the zenith to a point below the horizon

ID plate on optics head of Periscope at Wisconsin Maritime Museum
Time picture taken Sat Sep 25 11:19:24 2010
Location picture taken Museum Galleries
Wisconsin Maritime Museum
Manitowoc, Wisconsin
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