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systematic testing with bulbs fitted as separate appendages at the fore end of 

 the ship. 



Unconventional means and methods were tried to assess the behaviour and 

 interaction. For this purpose, geometrical bodies like spheres, cones, cylin- 

 ders, etc., were included in the programme (Figs. 2a, 2b, 2c, 2d, and 2e). 



The science of hydrodynamics already reveals the individual resistances 

 of geometrical bodies, also when they are towed in tandem formation at differ- 

 ent spacings between them. In choosing the unusual devices, the aim has been 

 to study their comparative interactions with the hull, rather than their direct 

 adoption as a resistance reducing mean. 



The circular streamlined axisymmetric body has been selected as the near- 

 est geometrical contemporary to the existing ship bulbs. Two ship models: one 

 of a coastal tanker and the other of a motor launch were selected to be subjected 

 to systematic testing. Some of the devices as fitted are shown in the accom- 

 panying photographs. The devices as tried may be subdivided into the following 

 categories according to their functions: 



(a) interference effect, 



(b) bow wave suction or flow deviation, 



(c) wave suppressors, and 



(d) wave scrapers or spears. 



Geoff>e'tr/cal h)oc//es 

 /n^er/cre/>cz 



o9 



A 



Fig. 2a - Passive means — geometrical bodies interference 



1100 



