Tilt
Tilt is the angle formed between the vertical of a shipboard fitting (such as a gun mounting or a director) and that of an idealized reference plane for the ship. These small imperfections in construction require corrective mechanisms for accurate gunnery.
Generally, tilt was only a problem when one instrument (such as a director) had to communicate an angular reading to another fitting (such as a gun mount) which might have a slightly different alignment. The usual remedy was to define a plane of reference for the ship and mount tilt correctors on the directors, elevation receivers and other sensitive instruments so they would "speak a common language" of elevation no matter what their angle of training.
Tolerance
The Royal Navy allowed gun mountings to have up to tilts of up to 20 arc minutes throughout the war, as the tilt correctors then in use could correct for this magnitude of error &mdashl in elevation. However, by the mid 1920s, the adoption of mountings of up to 40 or 45 degrees was anticipated, and the as-yet-untreated issue of deflection errors attributed to tilt would grow equal to the tilt error at 45 degrees elevation (about 8-10 knots of deflection on most sights), the decision was made to reduce the maximum tilt to 5 arc minutes in 1926.[1]
See Also
Footnotes
- ↑ Gunnery Branch. Addendum No. 2 to Director Firing Handbook, 1917, O. U. 6125(2), G. 10777/26, issued in September 1926.
Bibliography
