Sec. 59.10 



PROPULSION-DEVICE PERFORMANCE 



339 



A contribution by R. F. P. Desel, entitled 

 "Controllable Pitch Propellers in Ship Propul- 

 sion," appeared in Bureau of Ships Journal, 

 April 1956, pages 2-6. 



59.10 Performance of Miscellaneous Propul- 



Water Intake Through &rille\ 



Water Discharge Aft, Forming 



Propulsive Jets. 

 Under Bottom 

 of Boat 



Centerline of Ship-""''^ 

 for Single-Unit D 



Inflow " Outflow. 

 Downward 

 and Aft 



Inflow from 

 Forward 



Fig. 59. Da Explanatory Diagram for the 

 HoTCHKiss Propeller 



sion Devices. The general arrangement and 

 method of operation of the Hotchkiss propeller 

 are illustrated schematically in the diagram of 

 Fig. 59. Da. A drawing showing the use of a Gill 

 axial-flow propeller in a hydraulic propulsion 

 device is reproduced in Fig. 59. Db. 



It has not been possible to find in the technical 

 literature any published systematic performance 

 data on these and other types of miscellaneous 

 propulsion device, corresponding to the orthodox 

 characteristic curves for screw propellers. The 

 following may be mentioned as sources of refer- 

 ence information on the Hotchkiss propeller: 



(1) Hotchkiss, D. V., "The Hotchkiss Internal Cone 



Propeller," The Shipbuilder, 1931, p. 180 



(2) SBMEB, Apr 1937, p. 188. Illustrates "60-in Worm- 



Drive Cone Propellers for Wood Vessel." Also 

 May 1937, p. 321, and Jul 1937, pp. 382-384. 



(3) The Motorship, 1937-1938, p. 110 



(4) A lifeboat fitted with Hotchkiss cone propellers is 



illustrated and described on pages 45-50 of the 



13 January 1938 issue of Shipbuilding and Shipping 



Record. The following is quoted from pages 45-46: 



"The Hotchkiss system of propulsion consists 



of cones constructed of steel and provided with 



rotary impellers. One side of the cone is cut away, 



forming an aperture in contact with the water, 



which divides into inlet and outlet portions. 



As the impeller rotates, the centrifugal force of 



the water causes it to be projected tangentially 



from the larger end. 



Fig. 59. Db Longitudinal Section Through a Hydraulic Propulsion Device Utilizing a Gill Axial-Flow 



Propeller 

 This drawing, reproduced from page 111 of the July 27, 1939 issue of Shipbuilding and Shipping Record, shows a Gill 

 propeller (marked "rotor") with a close-fitting fixed shroud ring. In other installations the ring is attached to the blade 

 tips and rotates with the propeller. 



