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December, 1909 THE HUTCHISON MARINE TACHOMETER. The maximum of efficiency in the best entire The vehicle is the control in the hands of one man. manetivering of any accomplished by placing automobile is an excellent example. One man handles everything--steers, controls the engine, arranges' the proper ratio of gearing, and operates the brakes. If these duties were di- "TAE. MaRINE. REVIEW that which is possible with the func- tions divided between pilot and engi- neer, also demonstrates this fact. Instantaneous Comprehension As Good As Unit Control. Unfortunately such an arrangement is impracticable on a large steam- ship. The complication and unrelia- bility of the mechanism which would be necessary to accomplish this, far overshadows the liability to accident obtaining at present. However, there Fic. f. vided between two péfsdofs, not a fraction of the efficiency of control of the unit machine would result; in the congestion of traffic and speed at which the automobile trav- els would make such an arrangement an exceedingly dangerous combina- tion. Yet, that many of those: drtiv- ing automobiles could not qualify as a second class helmsman is not to be denied. The expertness with which one man will handle a launch, compared with fact, is no doubt that the bridge and engine room should be brought into closer relation to each other. When a sig- nal is given, the captain should be able to determine immediately as to whether it has been correctly exe- cuted. Fewer accidents would result. Man is not infallible; mistakes in transmitting the order to the engine room and in the interpretation and execution of orders are apt to occur, and do occur. The entire absence of tugs to as- sist in the docking of the steamers 531 of the great lakes -is,-the--first thing that attracts the attention of the salt water navigator. The absence, of tidal currents doubtless. removes one, of the difficulties. which at times confront the master of the ocean steamship, but nevertheless, extreme accuracy of control and perfect co-relation be- tween bridge and engine room are necessary for highest efficiency in handling. An indicator showing in pilot house or on bridge, and in the engine room, the exact speed of the engines assists in accomplishing this. Signals Call For: Definite Engine Speeds. Increased efficiency of control is also brought about by a standard speed of propeller .rotation for each signal. No two engineers respond to signals alike; whereas, with a depend- able and accurate tachometer to guide, and a definite pre-arranged rate of revolution ahead or astern understood, the man at the throttle has but to watch the indicator of the tachometer to produce definite results. A marine engineer, accustomed to the reciprocating engine, finds it con- fusing to operate turbines, with no rotating parts visible. An accident which would have proven serious was Nlatrowly averted by quick work with the helm recently, owing to the en- gineer on watch in the starboard en- gine room of a twin screw turbine steamer executing a signal for "full speed astern" with "half speed ahead." He opened the wrong valve, and be- ing unable to "see anything turning over" as he expressed it, was unaware of his mistake. The captain was like- wise unaware of the error, until 'he found the vessel was not swinging to starboard. It was then too late to depend on assistance from the screw and the helm was put hard Over just in time. By means of the Hutchison marine tachometer it is claimed. that two or more turbines or reciprocating en- gines can be operated at the proper relative speeds to minimize vibration without the necessity of counting revolutions or resorting to the ~hit and miss basis now obtaining. = Such an installation is also a coal saver. Every steamer has its most efficient cruising speed just as every steam plant has its most efficient load factor. When the revolutions corres- ponding to this speed have been 'as- certained, if the engineer on watch has an accurate and dependable tach- ometer to guide him, he can keep the engines at this point. The result will be economy in coal consumption.