High-Speed Planing Hull for Rough Water 



data were processed by a PDP-8E computer on line. Each channel 

 of data was analyzed at the rate of 200 scans per second and, at the 

 conclusion of each test run, an ordered listing of the peaks and 

 troughs of the pitch and heave motions and the accelerations at the bow 

 and CG were printed out in addition to statistics such as l/lO, l/3, 

 and average values. This instantaneous output of processed data was 

 extremely useful in interpreting the results. 



A comparison between the computed average CG accelerat- 

 ion and the results of model tests is tabulated below for a displace- 

 ment of 150, 000 lbs. , a speed of 45 knots and a range of LCG in a 

 head State 3 sea. 



It is seen that the computed values are approximately 0. 05g 

 larger than the measured values. The average values are used in this 

 comparison since, in random sea tests, the average statistics include 

 considerably more impact peaks than do the l/lO highest statistics. 

 Thus, the comparison between measured and computed results are 

 expected to be more reliable. It is interesting to note that a forward 

 movement of LCG from 34 ft. to 38 ft. reduces the impact acce- 

 lerations by nearly 3 5 %. 



The measured pitch and heave motions and added resistance 

 in waves are not presented in this paper, but are in substantial agree- 

 ment with results computed by the methods of Reference 3 . 



Coursekeeping Stability and Turning Performance 



The calm water stability and maneuvering characteristics of 

 the l/l6-scale model with appendages were investigated by means of 

 straight course tests and by rotating arm tests. In both tests, the 

 model was free to heave and pitch, but was restrained in yaw, roll, 

 surge and sway. The restraining forces and moments were measured 



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