[Reprinted from the PROCEEDINGS OF THE Royal Sociery, A. Vol. 89] 
Ship Resistance: The Wave-making Properties of Certain 
Travelling Pressure Disturbances. 
By T. H. Havetock, M.A., D.Se., Armstrong College, Neweastle-on-Tyne. 
(Communicated by Sir J. Larmor, F.R.S. Received October 7,—Read 
November 27, 1913.) 
1. In previous papers* I have investigated the wave-making resistance 
of a ship by comparing it with a certain simple type of pressure disturbance 
travelling over the surface of the water. In a recent papert on the effect 
of form and size on the resistance of ships, by Messrs. Baker and Kent of the 
National Physical Laboratory, reference is made to this point of view. The 
main work of these authors consists in the examination cf model results and 
the deduction of empirical formule of practical value. In addition, they 
connect the wave-making properties with the pressure distribution and have 
obtained graphs of the latter for various ship forms under certain conditions ; 
these curves show a range of negative pressure, or defect of pressure, between 
the positive humps of excess pressure corresponding to the bow and stern. 
The authors remark that this will have an effect upon the wave-making, but 
conclude that it is sufficient for their purpose to be able to state that such 
pressure disturbances, as they have shown to exist when a ship is in motion, 
will produce waves which will vary more or less in accordance with the theory 
referred to above. 
Under the circumstances it seems advisable to extend the mathematical 
* ‘Roy. Soc. Proc.,’ 1909, A, vol. 82, p. 276 ; also 1910, A, vol. 84, p. 197 ; also ‘ Proc. 
Univ. Durh. Phil. Soc.,’ 1910, vol. 3, p. 215. 
+ G.S. Baker and J.L. Kent, Trans. Inst. Nav. Arch., vol. 55(ii), p. 37 
(1913). 
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