RUDDER TRIALS, U. S. S. STERETT. 



By Assistant Navai, Constructors R. T. Hanson and J. C. Hunsakbr, 



U. S. Navy, Juniors. 



[Read at the twentieth general meeting of the Society of Naval Architects and Marine Engineers, held in 



New York, November 21 and 22, 191 2.] 



1. This paper was first prepared as a thesis submitted to the Depart- 

 ment of Naval Architecture of the Massachusetts Institute of Technology; 

 and the writers desire to express their grateful appreciation to Prof. Cecil H. 

 Peabody, under whose supervision, as head of that department, the tests 

 were conducted, for many helpful suggestions, both in the preparations for 

 the tests and in the analysis of results. 



2. The objects of these trials were: (i) to determine the moment of 

 pressure on the rudder in turning at various speeds and helm-angles; (2) to 

 compare these values with the corresponding values given by Joessel's 

 formula, and to obtain a coefficient of reduction thereon; (3) to establish a 

 formula, directly applicable to this particular type of vessel; and (4) to 

 investigate the condition of "meeting ship" with the helm when already 

 turning, and the condition of turning with engines reversed. 



3. It is believed that previous published turning trials have been 

 conducted at speeds not greater than 20 knots, and that particular interest 

 attaches to these trials on account of the high speeds (28 knots maximum) 

 at which they were run. 



4. The trials for the conditions of "meeting ship" and "backing" were 

 made for the purpose of obtaining data which, it was hoped, would be of 

 interest in the design of steering gear for ships of a type similar to that tested. 



5. For these turning trials, the U. S. S. Sterett, a destroyer of recent 

 design, was designated by the Navy Department. The trials consisted in 

 securing, with a recording, spring dynamometer, a continuous record of 

 tension in the standing part of one tiller chain, together with records of 

 time, helm-angle, and revolutions of both turbines. 



6. The results of the tests have been summarized in curves of twisting 

 moment, both maximum and on steady turning, coefficients of reduction 

 on Joessel's values, and an approximate empirical equation. 



TABLE OF PRINCIPAL DIMENSIONS, ETC., U. S. S. STERETT, DESTROYER. 



Built by Fore River Shipbuilding Co., Quincy, Mass., 1910. 



Length between perpendiculars 289 ft. o in. 



Length over all 293 ft. io| in. 



