-9- 



DISCUSSION 



The resistance of the targets at a given speed may- 

 be changed by a change in towpoint position., initial trim, and 

 initial displacement. Parts 1 and 2 of the program show that 

 the effect of change of towpoint position on model resistance 

 is small. Therefore,, in Part 3, it was decided to test only 

 the extreme forward and after positions of the towpoints. In 

 the course of these tests., no appreciable difference could be 

 observed in the maneuvering characteristics of the models when 

 the towpoint was moved from the extreme forward position to 

 the extreme after position„ 



Variation in initial trim does have a noticeable 

 effect on the resistance and spray formation of the models . 

 All of the models have more advantageous resistance and spray 

 characteristics at the higher speeds when trimmed by the stern. 

 When trimmed by the bow s all of the models had undesirable and 

 in some cases dangerous spray formations" at low speeds,, 



The models of the two sled- type targets, Model 4024 

 and Model 4025 s exhibited some slight tendency to yaw during 

 the maneuvering tests. Hard pounding in waves was also notice- 

 able,, The two boat-type targets heel the most in a cross wind. 

 As accurately as could be detected by eye, the boat-type sleds 

 towed equally well with bridle or with single cable attachment. 

 As had been noted on full-scale tows (2), during the maneuvering 



