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150 Kilowatt Diesel Generating Set on the United States War Department Hopper Dredges mum overall space and weight. The question of the cooling water circulation on the motorship is of importance. The engine cylinders are cooled to best advantage by the use of fresh water, which has the least corrosive effect upon the inaccessible passages within the castings. A sec- ond circulating system within the cooling coils for the fresh water, and having sea water as the cooling medium, can be best served by a centrifugal pump with its suction below the ship’s water line. For this particular service, as well as that for the cooling of oil, the quan- tity of the circulating sea water, be- ing dependent upon its temperature, which varies over wide limits, should be regulated by speed adjustment of the centrifugal pump, rather than by throttling. For this purpose, approxi- mately 10 per cent speed adjustment of the pump motor is recommended. Moderate sized equipment, usually below 30 horsepower is used for turn- ing the main engines slowly. For this service, the manual type of con- troller (usually cam or drum type) with separately mounted protective panel and resistors, is offered. Since the turning over operation may be continuous during the entire cycle or revolution of the main unit, resistors good for continuous service are need- ed in the armature circuit, so that the controller handle can be left on any point and the speed adjustment obtained over extended periods. By means of a separately mounted panel, overload and low voltage protection is obtained so that the motor will stop if sufficiently overloaded, or up- on substantial reduction or loss of the line voltage. Looking for examples of magnetic controllers in the engine room, one finds several varieties which are classed as semi-magnetic, and full- The former are more gen- erally used than the latter. For the automatic operation of pumps and compressors, pressure gages with re- lays, diaphragm and float switches are substituted for the ordinary form of push button operation. The plain starter arranged for bulk- head mounting with a push button placed on or near the motor to be started, is most frequently seen on shipboard. Except for the switch- board type of controllers, cabinets magnetic. MARINE REVIEW—November, 1927 should be supplied to protect the parts on the panels from accidental injury, or from dripping water or oil. The push button station makes it possible for the attendant. to start or stop the motor. Such equipment can be used for the fresh water and flushing pumps, compressors and re- frigerating machines for non-auto- matic operation, machine-shop group drive, engine room blowers, etc. (To be Continued) Norman -F.. Titus, chief of the transportation division, foreign and domestic commerce, department of commerce, addressed the Propeller club at luncheon Oct. 26, on the topic of shipping methods abroad. Mr. Titus recently returned from an ex- tensive trip abroad where he studied transportation and cargo handling facilities in different leading ports. Commodore Herbert Hartley, com- mander of the S. S. LEVIATHAN, flag- ship of the United States lines, was made a chevalier of the Legion of Honor by the French government when the vessel called at the port of Cherbourg in mid September. 59