coordinates X41»Y452,: Some of these computed 
distances will be longer than the corresponding 
taped values and some will be shorter. But, none 
  
of the differences should exceed that which would 
be expected knowing the probable accuracy of the 
tape measurements and of the photogrammetric 
  
triangulation. 
3. FIT-UP PREDICTION 
  
3.1 Targetting the Ship Halves 
  
As indicated in paragraph 2.2.1 it is desirable to 
use targets to identify specific points of interest. 
In the case of mating ship-halves, the primary points 
of interest are the "hard points" which should match 
between the halves,and the rolls of the bilges and 
gunnels. Figure 3 shows the target scheme used to identify 
these locations on the ship halves built by Sun. Note 
that targets were at as-built intersections of molded 
lines such as longitudinals with deck heads and stringers 
with inner or outer shells. Targets on the rolled surfaces 
were also placed on as-built molded edges, but not generally 
at specific points along these lines. Targets on the 
main deck were positioned along the punch marked centerline. 
These targets, as will be seen, allowed an analysis of the 
straightness of the joined centerline after the mating 
  
faces were mathematically joined. 
Target bases were 3-inch (nominal) squares of 16-gauge 
sheet metal painted flat-black on one side. A 
small hole was drilled through the nominal centers of 
the plates to facilitate alignment of the targets with 
  
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