Manoeuvrability and Propulsion of Very Large Tankers 



jet nozzles with larger diameters than 1.10 m may lead to an extension of the 

 speed range where this type of ship control has a superior manoeuvrability, 

 lowering at the same time the required pump power. 



Comparing the two types of cargo-pump-driven lateral thrust units, it is 

 found that at zero forward speed the ejector type doubles the specific thrust of 

 2-3 kg per installed pump horsepower of the simple nozzle system. At 5 knots 

 ship speed, the nozzle with an exit diameter of 1.10 m, which is representative 

 for the ejector system, requires about half the power of the plain nozzle system 

 with a manoeuvrability which, when expressed in maximum yaw angle rate, is 

 the same. 



Since it was found that at speeds above 5 knots the jet steering system can 

 only assist the rudder but not make it superfluous, the tail piece just behind the 

 propeller nozzle should be used as a rudder. Therefore it should be made mov- 

 able. 



REFERENCES 



1. van Manen, J.D. and Kamps, J., "The Effect of Shape of Afterbody on Pro- 

 pulsion," Trans. SNAME, 1959 



2. Nitzki, L., "Einige Weitere Untersuchungen im Zusammenhang mit der 

 Anwendung der A.G. "Weser"-Hinterschiffsform," Schiff und Hafen, 1962 



3. Hadler, J.B. and Cheng, H.M., "Analysis of Experimental Wake Data in Way 

 of Propeller Plane of Single and Twin-Screw Models," Trans. SNAME, 1965 



4. van Manen, J.D., "Size, Type and Speed of Ships in the Future," Third 

 Symposium on Naval Hydrodynamics, 1960 



5. Hadler, J.B., Morgan, W.B., and Meyers, K.A., "Advanced Propeller Pro- 

 pulsion for High-Powered Single-Screw Ship," Trans. SNAME, 1964 



6. Nichols, W.O., Rubin, M.L., and Danielson, R.V., "Some Aspects of Large 

 Tanker -Design," Trans. SNAME, 1960 



7. van Manen, J.D., "Open Water Test Series with Propellers in Nozzles," 

 International Shipbuilding Progress, Vol. 1, No. 2 (1954) 



8. van Manen, J.D., "Recent Research on Propellers in Nozzles," International 

 Shipbuilding Progress, Vol. 4, No. 36 (1957) 



9. van Manen, J.D. and Superina, A., "The Design of Screw Propellers in 

 Nozzles," International Shipbuilding Progress, Vol. 6, No. 55 (1959) 



10. van Manen, J.D., "Effect of Radial Load Distribution on the Performance of 

 Shrouded Propellers," Paper No. 7, The Royal Institute of Naval Architects, 

 March 29, 1962 



269 



