Binoculars of the U.S. Navy -- U.S. Naval Gun Factory Optical Shop & Annex -- Offset wedge attachment -- The Mk 42 Binocular -- Opticalman training schools ============================ The U.S. Naval Gun Factory optical shop in Washington, D.C. manufactured & repaired telescopic gun sights, and was established 1917 from the existing Optical Repair Shop. The USNGF Annex in Rochester, N.Y. was formed during WWI, when the Crown Optical plant in Rochester was commandeered, in an attempt to ensure quality and increase production. The Annex manufactured binoculars in large quantity, closed immediately after WWI, replaced by a temporary glass molding facility, and the Annex equipment was moved to a new shop at the NGF. There are reports that the Gundlach plant in Rochester was also used as part of the Annex. The role of exports to the U.K. is uncertain, though Crown 6 x 30s were exported. Binoculars produced at the Annex, based on surviving examples so marked, were: --3 x 50 Galilean, amber filters in swivel mounts inside the eyecups. --6 x 30 models were made in massive quantities, and were also used by the U.S. Army, examples marked U.S. Army Signal Corps are not scarce. The standard USNGF 6 x 30 is identical to Crown Optical 6 x 30s, which are distinctively heavy, and both carry 5 digit serial numbers in tiny digits on the rear hinge lug, by the objective. (One example of a Crown 6 x 30 is hand engraved U.S. Navy A-6, a mysterious inscription.) For Mark & Mod designations, see chart below. The 6 x 30 Mark XI is a later model, introduced in the late 1920s, waterproof, with an aluminum upper prism housing cover with sloped cutaway outer edge, 7 screws attaching the flat lower cover, and large rubber eyecups. One example is marked: 6 x 30, Mark XI No. 31, US Navy Bur of Ord, NGF, 1927. --10 x 40 Mark XII resembles the 6 x 30, with 7 screws through the bottom housing cover, waterproofed, and a sloped shoulder like the Mk XI. One example is marked: Mark XII No. 9, US Naval Bureau Ordnance, NGF 1931; and another example reads Mark XII No. 89. Note that the 1944 Schedule of binoculars copied below describes the Mark XII as a 10 x 45. --10 x 45 binoculars were made by the NGF in 4 or 5 styles, some experimental. One model used the Crown 6 x 30 body with 45 mm objectives (and possibly redesigned eyepieces), one example is marked Bureau of Navigation. Another 10 x 45 resembles the old B & L 10 x 45, with widely spaced objectives, and distinctive upper prism housing covers in a teardrop shape. Two examples are marked Bureau of Navigation, and one has the acceptance mark (NO) 6323. Another is marked 10 x 45 Mk VI Bureau of Ordnance. --The Mk 37 is a 9 x 63, modified at the NGF from a standard 7 x 50. --The Mk 1-1 is a pier mounted giant binocular, probably 20 x 120, with 45 degree offset eyepieces using rhomboid prisms. One example is marked Bureau of Ships, and has a stamped acceptance mark (not engraved, and assuming it is an acceptance mark), of a large N with an O around it, followed by 232. SCHEDULE OF BINOCULARS, NAVY DEPARTMENT, BUREAU OF SHIPS, FILE NUMBER S2407 - 533074. 8|2|44. MK | MOD | GENERAL ARRANGEMENT | CONTRACTOR | MAGNIFICATION | APERTURE | FIELD (DEGREES) | EYE RELIEF, MM | TRANSMISSION % | BUREAU | STATUS (1944) | REMARKS 6 | 0 | 68816-O | N.G.F. | 10| 45 | 4.2 | ---- | ---- | ORD. | OBS. | 6 | 1 | 68826-O | N.G.F. | 10| 45 | 4.2 | ---- | ---- | SHIPS | OBS. | 6 | 2 | 68839-O | N.G.F. | 10| 45 | 4.2 | ---- | ---- | SHIPS | OBS. | 6 | 4 | 68816-O | N.G.F. | 10| 45 | 4.2 | ---- | ---- | SHIPS | OBS. | 7 | - | 56588-O | N.G.F. | 6 | 30 | --- | ---- | ---- | ORD. | OBS. | 7 | 0 | 66673-O | N.G.F. | 6 | 30 | 8 | ---- | ---- | ORD. | OBS. | 7 | 1 | 66674-O | N.G.F. | 6 | 30 | 8 | ---- | ---- | ORD. | OBS. | 7 | 2 | 66675-O | N.G.F. | 6 | 30 | 8 | ---- | ---- | ARMY | ----- | 9 | - | 66686-O | N.G.F. | 3 | 50 | --- | ---- | ---- | SHIPS | OBS. | GALILEAN 10| - | 119666-O | N.G.F. | 4 | -- | 10 | 22 | ---- | AERO. | OBS. | 11| 0 | 119683-O | N.G.F. | 6 | 30 |8d40'| 15 | ---- | ORD. | OBS. | WATERPROOF 11| 1 | 119683-O | N.G.F. | 6 | 30 |8d40'| 15 | ---- | ORD. | OBS. | WATERPROOF 11|2-3| 141890-O | N.G.F. | 6 | 30 |8d40'| 15 | ---- | ORD. | OBS. | WATERPROOF 12| 0 | 132869-O | N.G.F. | 10| 45 |5d12'| 14 | ---- | ORD. | OBS. | WATERPROOF 12| 1 | 132869-O | N.G.F. | 10| 45 |5d12'| 14 | ---- | ORD. | OBS. | WATERPROOF 12| 2 | 132869-O | N.G.F. | 10| 45 |5d12'| 14 | ---- | ORD. | OBS. | WATERPROOF 14| - | -------- | N.G.F. | 6 | 30 |8d40'| 15 | ---- | AERO | OBS. | MK 11 WITHOUT MIL SCALE 15| - | 153551-O | N.G.F. | 7 | 50 |7d 2'| 14 | ---- | ORD. |EXPMTL.| BAKELITE 17| - | -------- | N.G.F. | 4 | 25 | --- | ---- | ---- | ORD. |EXPMTL.| 25| - | -------- | N.G.F. | 10| 70 | --- | ---- | ---- | ORD. |EXPMTL.| ONLY 2 MADE 25| 1 | 244100-O | N.G.F. | 10| 70 |5d10'| 13.5 | 79.6 | ORD. |EXPMTL.| ALTERED MK 13; SUPERSEDED BY MK 37 37| 0 | 254211-O | N.G.F. | 9 | 63 |5d42'| 13.5 | 78.4 | ORD. | CURR. | MK 13 MODIFIED OBJECTIVE References: Crowell, Benedict. America's Munitions 1917-1918. Washington: Government Printing Office, 1919. (p577-9) (Navy Department, U.S.A.) Annual Reports of the Navy Department for the fiscal year 1919. Washington: Government Printing Office, 1920. (Department of the Navy, Bureau of Ordnance) Navy Ordnance Activities: World War 1917-1918. Washington: Government Printing Office, 1920. ================================ The 'Binocular Offset Wedge Attachment, Mark 7' was made by Polaroid for WWII 7 x 50s. It is two short metal cylinders that fit over the objectives and are held by a clip. In each cylinder is a clear plastic wedge with seven holes drilled through it (along the optic axis), covered by a thin plastic window. The thick plastic is about 7 mm thick on the right edge and 15 mm thick on the left edge. It has the effect of laterally offsetting the field of view, retaining a faint image of objects directly in front (the faint image is from the holes drilled through the wedge). Some were labeled for attachment to Mark 13 binoculars. A 'Schedule of Binoculars' from 1944 has it listed with the Mark 22, and the Mark 27 has a note, 'wedge attachment omitted' (as if it was issued with the Mark 22). These are all B & L 7 x 50s. There is a variant that is a stand-alone unit with a handle. It is used in conjunction with naval gunfire training. The weapons officer gives a set of coordinates(as determined through the bino with the offset wedge assy.) of an actual target to the mount captain. The idea of the offset wedge assy., is to offset the angle without affecting the range. In this manner the target is not actually distroyed, but the rounds will appear to be on target. --Peter Abrahams and Earl Osborn =============================================================== USN Mark 42 During WWII, the US Navy listed three models of very wide angle glasses: the Mark 43 Sard 6 x 42 at 11 degrees 50 minutes (60 oz.); the Mark 41 B & L 7 x 50 at 10 degrees (58 oz.); and the Mark 42 Pioneer 7 x 50 at 10 degrees (51 oz.). An image of a Mark 42 is posted at: http://home.europa.com/~telscope/mk42j.jpg 130 kb Markings: 7 X 50, 10 degree, SER: (removed), DES. PAT. 137441, PIONEER. This binocular uses triplet objectives; and mirrors of solid aluminum instead of prisms, this is a poor material to use for a reflecting surface & should probably be considered experimental (especially since the back of the mirrors are the outer shell of the body, with the rubber covering glued onto the mirrors!). Although it is only slightly lighter in weight than the others, it is a very comfortable binocular to use due to the wide body, and the user can focus without moving the hands from a normal grip. The eyepieces appear similar to the Mk 43 but are not identical, eye relief is 14 mm, although the rubber eyeguard prevents this close approach. Pioneer Instruments seems to have been associated with Kollsman, and a division of Bendix Aviation in Bendix N.J. (aircraft instruments). Patent: 2,424,283 J.R. Miles Mark 42 binocular 7/1947 ============================ The OM rate for opticalmen started in 1947. During WWII, instrumentmen (IM rate) repaired typewriters, etc. & optics. There were three classes of schools for OMs: A school: basic, binoculars, alidades, sextants, machinist skills. Great Lakes main school, smaller school in Pensacola Florida, later the Great Lakes school was moved to Florida. B school: rangefinders. Located at the Naval Gun Factory in Washington DC, closed in the early 1960s. Students had to be ranked 2nd class or higher. C school: periscopes. Located at New Groton Conn, where the Kollmorgen factory that made USN periscopes was sited. Students had to be ranked 2nd or 1st class. There was also training at the Long Beach Naval Shipyard, on general optics for rangefinder operators; 100 operators for 4 battleships were trained. The U.S. Army optical repair school at Aberdeen would sometimes train repairmen for the Marines, who used tanks & field artillery, not utilized by the Navy. (From Jim Rose) =================================== Home page: http://www.europa.com/~telscope/binotele.htm