OP-1063   January 1944
The Stable Element
Mark 6 and Mods


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The Stable Element is located adjacent to the Computer in the Plotting Room and performs two major functions:

1. It measures Level and Cross Level angles caused by variation of the position of the deck of the ship with respect to the horizontal, and utilizes these angles in such a manner as to keep the lines of sight of the telescope and the rangefinder positioned automatically on the target while the ship pitches and rolls.

2. It provides means for firing the guns.



Ordnance Pamphlet No. 1063 describes the theory, care, and operation of the Stable Element Mark 6 and Mods. Data on the associated Control Panels Marks 7 and 8 are included. Although Ordnance Pamphlet No. 1063 was written primarily for the Stable Element Mark 6 and Mods., occasional notes have been added to indicate wherein the Stable Element Mark 5 differs from the Stable Element Mark 6.





The first major function listed above is the basic duty of the Stable Element. The method by which the instrument performs this function is described in detail in the section on Application, but it may be briefly stated here that a gyroscope is the heart of the instrument, the gyroscope providing a horizontal reference plane about which Level and Cross Level Angles are measured as the ship pitches and rolls. The construction is such that any motion of the ship's deck with respect to this plane causes relative motion between the gyro and the gimbals in which it is mounted.

Any motion or angular displacement due to these causes is measured by maintaining a pair of follow-up coils, which are mounted on one of the gimbals, in alignment with a magnet mounted on the gyro case. This is accomplished by an electronically actuated motor-driven follow-up mechanism. As the follow-up mechanism acts to keep the follow-up coils aligned with the magnet, the angle generated by each gimbal is indicated about its corresponding (Level or Cross Level) axis on dials calibrated in minutes of arc.

In addition, the angle generated by each gimbal is also applied to Synchro generators and to mechanical output shafts for transmission to other instruments or elements to be controlled.

The instrument also provides means for automatically firing the guns.  The guns may also be fired by means of the firing keys on the front of the housing.  Settings are possible for:
1. Continuous Fire
2. Automatic Firing in Selected Level
3. Automatic Firing in Selected Cross Level
4. Hand Firing in Level
5. Hand Firing in Cross Level

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OP1063 The Stable Element     33.4 mb

Related material: Computer Mark 48 Mod 1