Ordnance Pamphlet 1171 (Preliminary, 17 April 1944) is the U.S. Navy’s technical manual for two families of shipboard optical rangefinders. Rangefinders Mark 58 and Mark 58 Mod 1 were used in Gun Director Mark 50; Rangefinders Mark 65 and Mark 65 Mod 1 were designed for the exposed deck mount Rangefinder Mount Mark 65.
The pamphlet covers the complete optical system of each instrument — wedge windows, penta prisms, correction and compensator wedges, searchlight filters, main objectives, stereoscopic reticules, erecting lenses, ocular prisms, rayfilters, and eyepieces — together with the range scale reading system and internal adjuster system. Structural detail extends to the optical tube assembly, gimbal joint, height adjuster, main objective cells, stereoscopic reticule cells, end box assembly, penta prism mounts, wedge window cells, adjusting drive assembly, compensator and correction wedge assemblies, collimator assembly, and main eyepiece assembly.
The adjustments section covers height, interpupillary distance, focus, internal adjustment, rayfilters, searchlight filter, and assembly adjustment. Accuracy, unit of error, care of the rangefinder, gas filling, and lubrication and cleaning complete the Rangefinder Mark 58 coverage. A separate section describes the principal differences in Rangefinder Mark 58 Mod 1. The Rangefinder Mark 65 section covers the end box bracket assembly, measuring knob assembly, and auxiliary sight, followed by Rangefinder Mark 65 Mod 1 and a summary of principal differences among all four variants.
Using the viewer: Use the Full Table of Contents button (bottom-right) to jump to any section. Use the double caret (») symbol at top right of viewer to adjust scrolling.