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ed through gears to four 500 kilowatts, 90 revolutions per minute, 120/240-volt genera- tors. The turbines operate at 300 pounds gage and 200 degrees Fahr. superheat. One of them is arranged for non-condensing operation at reduced load with 175 pounds gage steam pressure and 15 pounds gage back pressure. The generators are of the modified 3-wire type each having a compensator for supplying the excitation neutral bus. The neutral for the 115/230 volt 3-wire lighting system is supplied from two 300-am- pere rotary balancer sets arranged for opera- tion singly or in parallel. The main direct current switchboard consists of thirteen panels, the overall dimension be- ing 29 feet 8 inches long by 7 feet high, ex- clusive of the blank filler sections at the top. For control of auxiliaries which cannot be conveniently supplied directly from the main direct current switchboard, twelve power dis- tribution panels are installed about the ship. A total of 187 motor driven auxiliaries are installed with an aggregate rating of consider- ably more than 3000 horsepower. The motors are, in general, of the enclosed ventilated drip proof type for under deck auxiliaries and en- Standardization Sea I rials IS not customary to conduct exhaustive sea esi for merchant vessels such as are de- manded for ships of the navy. In this re- spect, therefore, the S. S. PRESIDENT HOOVER has established a unique record. It was deter- mined to carry out careful standardization trials and a continuous run at sea in order to determine accurately, speed, power, revolu- tions and fuel consumption. The results were highly satisfactory and gave proof of skilful design of hull and machinery showing that the estimates were well founded and conservative. The data obtained is of great value to the Science of naval architecture and marine engi- neering as it has heretofore seldom been avail- able in such completeness and with such a de- gree of confidence in its accuracy. The S. 8. PResIDENT Hoover sailed from the Plant of the Newport News Shipbuilding and Dry Dock Co. at 5:00 a.m., Tuesday, June 16, 1931, for her official trials off Rockland, Me. The vessel made the run to Rockland at an average speed of about 20 knots except for a few hours during the early morning of June S. S. PRESIDENT HOOVE? closed waterproof for deck auxiliaries. Prac- tically all controllers are of the magnetic con- tactor type with drum type master controllers for the cargo winch and warping capstan mo- tors and push button control for others. The emergency lighting and power system consists of two 15 kilowatts, 120/240-volt, 3- wire direct current generators each directly connected to a gasoline engine, also a 140 ampere-hour 240 volt (120 cell) storage bat- tery. The battery is installed primarily as a final reserve for the radio. but its capacity is sufficient to supply also the emergency lights for about one-half hour. Upon failure of the main supply the emergency bus is immediately transferred to the battery by an automatic throw over switch. A special manually oper- ated switch is provided whereby the radio sys- tem can be supplied from the battery. Power from this emergency plant is also available for the gyro compass, running lights, 18-inch searchlight, whistle operator, fire alarm, and watertight doors. There is a total of 50 miles of electric light- ing and power cable ranging in size from 4- inch to 2 inches in diameter and containing a total of 750 miles of copper wire. On Board the S.S. President Hoover During Standardize tion Trials off Rockland, Me——Left to right—Mrs. J. Harold Dollar; Capt. Roger Williams; J. Harold Dollar; Mrs. K. Ferguson; and Capt. C. A. McAllister 17 when she was slowed down on account of fog. Preliminary data obtained by observing the speed between Chesapeake light vessel and Winter Quarter light vessel indicated that the ship would exceed her guaranteed speed of 20.5 knots at the designed shaft horsepower of 26,500. It was also evident that the fuel MARINE REviEw—August, 1931 35 oe