PROGRESS IN MARINE CONSTRUCTION — GRACIE. 699 



is coupled direct to the steam turbine and the latter to the pro- 

 peller shaft, the pump and water turbine being placed in one casing 

 and so designed that the frictional and eddy losses are reduced as 

 far as possible. Some small installations have been fitted for marine 

 purposes, a transmitter has been tested with a load of 10,000 shaft 

 horsepower, and it is proposed to fit several large German vessels 

 with the system. A transmission efficiency of about 90 per cent is 

 claimed at full load, with a slight reduction at light loads. The 

 ratio of primary to secondary speed is normally about 5:1, but trans- 

 mitters could be designed for larger ratios. 



Electrical transmission has now been applied to several vessels. 

 Alternative schemes have been tried in which the power is generated 

 by steam turbo-generators, and by generators driven by Diesel oil 

 engines, and applied to the propeller by alternating-current motors. 

 Considering the transmission efficiencies likely to be attained and 

 the increased weight and initial cost of the installation, it does not 

 appear probable that a system of this kind will be able to compete 

 successfully, in ordinary cases, with the direct-driving engine or 

 mechanically geared turbine. Where, however, power has to be 

 provided for other than propelling purposes (in which case the same 

 generating plant could be available), it is possible that this system 

 would have advantages. 



Within the period under review, vessels built solely for the purpose 

 of carrjdng cargo have undergone notable development. The prin- 

 cipal object of the owner of such vessels is to secure improved econ- 

 omy in each successive addition to his fleet, speed and accommodation 

 being secondary considerations. And here again I have the same 

 story to tell — the story of increase in dimensions and of reduction in 

 fuel consumption in relation to work done. 



The following table shows the steady advance in the vessels of one 

 well-known line of cargo tramps: 



Tons, dead-weight. 



1895 6, 400 



1899 7,200 



1905 8,200 



1912 9,300 



1913 9,600 



The speed has remained practically constant at 11 knots, but while 

 the 6,400-ton dead- weight carrier of 1895 developed 1,400 indicated 

 horsepower and consumed 24 tons of coal daily, her successor of to- 

 day can carry 9,600 tons and steam at the same speed on an expendi- 

 ture of only 32 tons daily for 2,300 indicated horsepower. Fifty 

 per cent more dead weight is carried and 64 per cent more power 

 developed, but only 33 per cent has been added to the coal account. 



