Page 540 - Practical Design Ships and Floating Structures

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Physically, the wave effect included in the effective speed is less important or may be not reasonable
for the propulsion characteristics behind the ship. However, due to possible errors in the measurements
for one specific ship, this hypothesis has to be proved by analyzing measurements of other ships.
70 70
60 60
50 50
3 40 E 40
a 30 n 30
1
1
20 20
10 10
0 0
00 05 10 15 20 25 00 0.5 1.0 1.5 2.0 2.5
v,,I~/~I V,,[m'SI
Figure 9: Delivered power at propeller as a Figure 10: Delivered power at propeller as a
function of the effective speed function of the blockage speed

6 CONCLUSIONS
Based on a novel analysis of model tests for an inland ship-model and a container ship-model at
different water-depths conducted in the Shallow Water Towing Tank Duisburg (VBD), a new method
is proposed for resistance and propulsion prediction of the ship performance in the subcritical speed
range and in a not too extremely shallow water by using an effective and blockage speed defined by
the mean sinkage. Whereas the total resistance is found to be a unit function of the effective speed and
independent of the water depth, the delivered power at propeller at a ship self-propulsion point
corresponding to the effective speed could be considered as a unit function of the blockage speed.

Acknowledgement
This work was partially supported by the Ministry of Education and Research (BMBF) of the Federal
Republic of Germany. The author is grateful to Mr. Lochte-Holtgreven for conducting the model
experiments.

References
Emerson, A. (1959): Ship Model Size and Tank Boundary Correction Journal of North East
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Graff, W., Kracht, A. and Weinblum, G. (1964) : Some Extensions of D.W. Taylor's Standard Series,
Transactions of Society of Naval Architects and Marine Engineers, Vol. 72.
Gross, A. & Watanabe, K.(1972): On Blockage Correction Proceedings of the 13'h lTTC,
BerlidHamburg.
Horn, F. (1932): Hydrodynamische Probleme des Schiffsantriebs. Editor: G. Kempf und Foerster
Jiang, T. (2000): Ship Waves in Shallow Water. Habilitation Thesis, Mercator University Duisburg,
Germany.
Kim, H.C.(1963): Blockage Correction in a Ship Model Tank. Report of Michigan University
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Lackenby, H. (1963): The Effect of Shallow Water on Ship Speed The Shipbuilder and Marine
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Landweber, L.( 1939): Tests of a Model in Restricted Channels. TMB-Report 460.
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