POWER AND SPEED TRIALS OF TEN THOUSAND DEADWEIGHT-TON 



TANKER. 



By H. A. Everett, Esq., Member. 



[Read at the twenty-ninth general meeting of the Society of Naval Architects and Marine Engineers, held 



in New York, November 17 and 18, 1921.] 



The following description of the trials of a modem oil-carrying steamer of good size 

 are presented, not with the idea of showing an exceptional performance but with the thought 

 that extensive progressive speed trials of a merchant vessel at full load draught in conjunc- 

 tion with the predicted performance, based on model experiments, will prove useful informa- 

 tion to members of this Society. Incidentally there are several points in the working up 

 of the data which differ from the methods commonly used for merchant vessels. 



GENERAL DESCRIPTION. 



The ship on which the trials were made was built by the Union Shipbuilding Company 

 of Baltimore and was a new, steel, longitudinally framed, bulk oil carrying steamer, and with 

 the characteristics tabulated as follows. The trials were run April 19, 1921 : 



Length (O. A.) 436' 1" 



Length (B. P.) 419' 3" 



Breadth (Mid.) 56' 3" 



Depth (Mid.) 33' 4" 



Class — Lloyd's, *100 A-1 ; American Bureau, *A-1. 



Draught on trial, forward 25' 6>^ " 



aft 25' 7" 



mean 25' 6^" 



Trial displacement (fresh water) 13,390 tons. 



Wetted surface 39,160square feet. 



Block coefficient .801 



Propeller — 4 bronze blades, steel hub, 18" 0' diameter, 15' 6" pitch. 



^ . n . • 1 • 27" X 45"X 75" 

 Engme — One tnple expansion, ^, 



Boilers— Three S. E. Scotch, 15' 10" diameter by 11' 4" length. 

 Furnaces — Nine 46" diameter. 



Total heating surface 8,952 square feet. 



Total grate surface 189 square feet. 



Working pressure 195 Jbg 



S. & K. oil burners. 



The model was towed at the U. S. Experimental Model Basin in Washington, D. C, 

 and the results of these tests are given on Plate 63. 



THE TRIAL COURSE. 



The trials were run over a measured mile in Chesapeake Bay, off Kent Island and 

 nearly opposite Annapolis. The course is an excellent one, with a depth of about 120 feet. 



