3.5.2.4 
3.5.2.5 
3.5.2.6 
Racking of the Transverse Section 
  
In addition to the planarity of the 
cut the shipbuilder must also know how 
"square". the as-built section is. - This 
is easily determined simply by computing 
a few long distances between points using 
their transformed coordinates. Figure 
i3 illustrates the results of such 
computations. 
Perpendicularity to Centerlíne 
  
Figure 3 showed that targets were set 
along the punch marked centerline on the 
main deck. Photogrammetrically derived 
coordinates for these targets, after the 
transformation described in paragraph 3.5.2.1, 
would all ideally have zero offset and constant 
elevation. Systematic deviations from the 
ideal indicate a lack of perpendicularity 
between the plane of the cut and the ship's 
centerline. Figures 14 and 15 depict typical 
graphic presentations of such analyses. 
Circularity of Rolled Surfaces 
  
Turns on the gunnels, bilges and inner 
shells are designed to be arcs of circles 
and the shipbuilder desires to know how 
close to true circles these turns are 
fabricated. Coordinates of all points on 
each turn: are processed through a best-fit 
circle program which computes the coordinates 
-21-