DISCUSSION ON MAY MEETING PAPERS. 39 



which is now being equipped, the engines were run at 200 revolutions per minute and the 

 complete equipment weighs about 20 pounds per horse-power less than the original engines. 

 In both cases they are two cycle ; the propeller speed is not altered. 



Referring to the twelve disadvantages of electric drive: Nos. 1, 2, 3, 4, 5, 6, 9, 11 and 

 12 are based on the erroneous assumption that flimsy and inefficient engines are being used; 

 Nos. 7 and 8 must have been written without investigation. (Laughter.) 



Referring to No. 10, if this is to be construed in its broadest sense to cover all possible 

 troubles from grounds or short circuits in generators, motors, control and wiring, investi- 

 gation will show that with the low voltage and high class of marine insulation which is being 

 used, there is less liability of trouble than may be expected with a high-pressure air system. 



For the reason that Diesel electric drive has been referred to, I would like to take the 

 opportunity of mentioning a few points that have been given most serious consideration by 

 shipowners. There are several, but, imfortunately, I have not time to go into all of them. 



The Chairman : — They can be printed, Mr. Dickinson. 



Mr. Dickinson : — Yes, sir. 



Some authorities of international reputation maintain that single-screw cargo ships are 

 more efficient than twin. 



I note that the authors figure on only 15 per cent more for Diesel oil. From some recent 

 quotations it would seem that the difference is greater than this by probably 30 or 40 

 per cent. 



When apparatus of equal quality is being compared, the same personnel should be 

 required for a turbine ship as for an engine ship. 



It is noted that the authors allow the same depreciation and general expenses for the 

 steamer as for the motor ship. It would be right to expect somewhat higher maintenance 

 on reciprocating machinery. 



With regard to the general use of electricity, Mr. Smith made a remark that it is not 

 being done in England. Well, that is interesting if true, but it is being done in England. 

 One of the biggest shipbuilders in the north of Ireland is actually building and equipping an 

 electrically driven cargo ship at the present time. 



The sum and substance of the matter has been said several times, that for each class 

 of freight the proper ship must be put in service. The English had shown us this before 

 the war. One company would have several classes of ships, more expensive and more effi- 

 cient machinery for the longer routes, and less expensive and slightly less efficient machin- 

 ery for the shorter routes. The whole subject of electric drive is altogether too much for this 

 evening. (Applause.) 



The points of particular interest which should be given special study when propelling 

 machinery for ships is under consideration are the following : 



1. Reliability. — Several engines of moderate size and of proportions and speed which 

 experience has demonstrated to be most reliable instead of one or two large direct-con- 

 nected engines each having many cylinders. The failure of any one of these cylinders would 

 cripple the engine. 



2. Maneuvering Ability. — Propeller can be reversed rapidly and continuously (fewest 

 motions to maneuver ship). 



3. Simple Engines. — Engines not reversed nor run at reduced speed; may be started 



