Naval Photo Interpretation 
  
Fig. 4. 
A close study of this low oblique proves that there 
are not less than four different wake patterns, probably 
as a result of four different hull designs. ; 
on the other hand, is quite different, formed as a narrow, 
single stream about one third as wide only as the central 
stream of the right-hand couple. 
Of the two vessels down to the left in the picture, 
with arrow-head patterned bow waves, the stern wake of 
the left one is more or less without any side-streams, and 
because of that there is a conspicuous dark area between 
the bow wave and the wake. The vessel to the right, on the