Buffington, Hamilton, and Moore 



on the sea floor from outside the sphere. When the two spots coin- 

 cide at a maximum measured fore-and-aft inclination with the thwart- 

 ships axis horizontal, the horizontal plane of symmetry of the sub- 

 mersible is exactly parallel to the sea floor and an interior reading 

 can be made which measures, exactly, the slope of the sea floor. 

 The two projectors are small, simple, and fortunately, not subject 

 to refraction problems. The details are the subject of a technical 

 memorandum currently being published by NEL. 



Fig. 1 illustrates the basic geometry involved in the installation 

 aboard DEEPSTAR 4000. The forward of the two light projectors is 

 mounted at maximum distance from the sphere, on the fore-and-aft 

 axis, and is adjusted so that it projects its spot vertically downward 

 or normal to the basic plane of horizontal symmetry of the submer- 

 sible. The second projector is also mounted on the fore-and-aft axis, 

 but next to the sphere. It is adjusted so that its beam shines oblique- 

 ly, and its spot coincides with the spot projected by the vertical pro- 

 jector on a plane which is tangent to the bottom of the sphere and, at 

 the same time, parallel to the horizontal plane of symmetry of the 

 submersible. 



OBSERVERS 

 SPHERE 



FORE & AFT 

 AXIS THROUGH 

 HORIZONTAL 

 PLANE 



\ 



u / n I / 1 III /irnii II 1 1 1 1 II II III II 1 1 1 iiiiiii 



^/ 



COINCIDENT 

 SPOTS 



1 1 1 1 1 II IIIV 



FLOOR OR \ 



SEA 



CALIBRATION PLANE 



VERTICAL AXIS NORMAL 

 TO HORIZONTAL PLANE 



Fig. 1 - Lateral Aspect. Geometry for initial mounting and 

 adjustment of inclinometers for measurement of a level sea 

 floor. The horizontal plane of the submersible is parallel 

 to the plane of the sea floor (or plane tangent to the sphere 

 base) when the light spots coincide. This situation obtains 

 regardless of the slope of the sea floor. The only change is 

 angular rotation of the entire relationship with regard to ab- 

 solute horizontality . 



83 



