38 



Towing Speed, 2.0 Knots 



Towing Speed, 6.0 Knots 



Towing Speed, 8.0 Knots Towing Speed, 10.0 Knots 



Figure 32 - Photographs of the TMB 48. 6'- Inch Displacement 

 Float Being Towed 



These tests were made under loads imposed by the 50-pound weight towed from the after towpoint. 



The model towed stably up to the highest speeds shown on Figure 30 

 for each loading condition. Above these speeds there occurred an oscillatory 

 instability in roll which appeared to increase with speed. This instability 

 was observed to occur at the speed at which actual transition upward through 

 the water surface (as defined for the TMB planing float in the foregoing) 

 began. However, no attempts were made to investigate this phenomenon further, 

 since the float, which had been designed for a specific purpose, performed 

 satisfactorily under all loads throughout the speed range originally specified. 



