-6- 



speeds 5 cable lengths, and towpoint positions For these tests the 

 models were fitted with target screens. The targets were 

 towed by a 1/16- inch diameter steel cable connected to the 

 models by a loop of wire with a breaking strength of about 75 

 pounds. AH turns were 180 degrees with the radius of turn 

 maintained as nearly equal to the length of cable as practicable. 

 All models were towed at the heavy displacement and at the trim 

 which gave minimum resistance in Part 1 of the test program. 

 The BuShips designs were towed both with conventional bridle 

 and with single cable attachment. The TMB design was towed 

 with single cable attachment only. When the Bureau of Ships 

 designs were towed with single cable attachment the point of 

 attachment was located midway between the extreme forward and 

 after locations used for the bridle attachment. Motion pictures 

 were taken of the models in action and a print of the film con- 

 stitutes a part of this report,, 



Part 4 of the program consisted of expanding to full 

 scale the data gathered in Part 2 of the program and presenting 

 curves of estimated horizontal drag of the target including 

 simulated cable load and horizontal cable tension with varia- 

 tion of speed and length of cable. 



It was not possible in all cases to obtain the trims 

 by the stern specified in Reference (1) without exceeding the 

 specified displacements. In such cases the models were trimmed 

 the maximum practicable with the available ballast. 



