64 PROGRESS IN TURBINE SHIP PROPULSION. 



as with both. A compact arrangement of the double pinion double reduction gear 

 representing latest practice is shown in Fig. 6, Plate 33. 



Of necessity the cross compound turbine installation with its double pinion gear 

 is more costly than the single complete expansion turbine, and with keen competition 

 will not be installed unless shipowners recognize its manifest advantages. So far as 

 the writer has observed, owners seem quite indifferent to the probable reliability of 

 machinery so long as they secure insurance and the protection of the classification 

 societies. The plea is therefore made by the author that underwriters, in collabora- 

 tion with the classification societies, should discriminate in insurance rates between 

 types of installations having manifestly differing degrees of reliability. 



No doubt single-screw steamers will frequently be driven by single complete ex- 

 pansion turbines, at least for low powers. An example of a small sized installation 

 1,500 horse-power is shown in Fig. 7, Plate 34, and attention is called to some of 

 its features. The double reduction gear elements are arranged one above the other 

 with the high-speed pinion uppermost. This elevates the turbine axis and permits 

 the condenser to be located immediately below the turbine, permitting the exhaust 

 to issue from the under side of the turbine and pass vertically downwards to the 

 condenser, much simplifying the removal of water. One end of the turbine is car- 

 ried directly upon a bracket integral with the gear case, the other by the exhaust out- 

 let being set directly upon the condenser. The condenser is secured by its upper sur- 

 face to seatings, eliminating disturbances to alignment on account of expansion of 

 the condenser. 



There appears to be much apprehension in the matter of the reliability of tur- 

 bine-geared steamers, and if current rumor may be relied upon there have been 

 many failures, which, with more careful design or by employing the best in the art, 

 would seem to have been wholly unnecessary. To correct such an impression. Table 

 II gives a list of all vessels equipped with the floating frame gear and Westinghouse 

 turbines. The table states the date on which the vessel entered service, the power 

 of the installation, and approximately the miles traveled up to the present time 

 (September i, 1918). 



Some troubles have been experienced as are certain to occuf with all kinds of 

 machinery. Since there must be a large human element, footncncs are appended, 

 plainly stating the character of the troubles. 



