36 DISCUSSION ON MAY MEETING PAPERS. 



Steam ship, Motor ship, 

 single screw. twin screw. 



Length, feet 425 425 



Beam, feet 56 56 



Depth of shelter deck, feet \ 38 38 



Displacement, tons . 14,050 14,050 



Gross tonnage, tons 7,100 7,100 



Deadweight, tons 10,050 9,500 



Capacity (bales), tons 497,000 493,000 



Total oil bunker capacity, tons 1,479 1,215 



Oil consumption per day at sea, tons 35.9 14.55 



Oil consumption per day in port, tons 5.0 0.75 



S. H. P 3,100 



I. H. P 3,870 



Speeds in knots 12 12 



R. P. M 90 105 



Fuel oil consumption per S. H. P. of main engines, all purposes, pounds 1.08 



Fuel oil consumption per I. H. P. of main engines, all purposes, pounds 0.35 



Total weight of propelling machinery, per cent 100 223 



Total cost of propelling machinery, per cent 100 209 



Total operating expense per year, per cent 100 94 



Total gross earnings, per cent 100 105 



Total net earnings per year on initial investment, per cent 100 119 



Mr. W. M. Huskisson, Member: — I would like to make a few remarks respecting the 

 first paper which has just been read. The authors have mentioned the solid injection 

 of fuel by mechanical pressure without the aid of air blast. This system has been invented 

 by Sir James McKeclinie and used by Messrs. Vickers since they abandoned the use of the air 

 blast injection. 



I would like to call your attention to the sentence in the paper which reads as follows : 

 "The chief difficulties encountered with such a system are in getting good combustion at all 

 running speeds and loads and the elimination of the shock in the cylinder, which is apt to 

 occur with a sudden rise in pressure when fuel is injected." 



This is a remarkable statement, because no difficulties such as those mentioned have 

 occurred. Fortunately, one of our ships happens to have arrived in this port today, so I 

 took the opportunity of ringing up the chief engineer and speaking to him on this point. He 

 stated that during the voyage out they ran into a fog and had to reduce the revolutions from 

 118 to 80 revolutions per minute for over one day, and he also mentioned that in coming 

 up the Manchester Ship Canal it was necessary to reduce the revolutions to 40 revolutions per 

 minute (this nm takes about eight hours), and the combustion was perfect as shown by 

 the transparent exhaust at all speeds. I cannot understand why any sudden rise in the pres- 

 sure of the fuel should be anticipated, as special means are taken to avoid this, and I think 

 that the authors' fears of trouble on this score are born of ignorance. 



The authors further go on to say that the advantage claimed is that the compressor 

 troubles are entirely eliminated with a correspondingly higher mechanical efficiency obtained 

 than with air injection. This is quite true. 



Now one would think from this that the advantage mentioned was the only advantage 



