40 



Towing Speed, 2.0 Knots 



Towing Speed, ^.0 Knots 



'^^ 



Towing Speed, 7.0 Knots Towing Speed, 10.0 Knots 



Figure 34 - Photographs of the TMB 48.6-Inch Displacement 

 Float Being Towed 



These tests were made under loads imposed by the 100-pound weight towed from the forward towpoint. 



Hence, the total drag is chiefly composed of wave-making and form drag for 

 the conditions under which the displacement float operates. For purposes of 

 analysis, accordingly, the coefficients of total drag are assumed to have 

 little dependence on the Reynolds number. 



The humps in the curves of Figure 30 indicate the speeds at which 

 the bow and stern waves are in phase, giving rise to large wave-making resist- 

 ance. With an Increase in speed beyond the humps in the curves of Figure 30, 

 the resistance was actually found to decrease for the two higher loading con- 

 ditions. This is due to the fact that the float under these conditions became 

 sufficiently submerged so that wave-making resistance was greatly reduced, 

 whereas the form or pressure drag and the frictional resistance continued to 

 increase. For loads imposed by the 50-pound weight towed from the after 



