in the normal position for storage, whereas in the second test they 

 were left in the water. The times required to complete the one 

 nautical mile speed runs are listed in the table below. 



Propellers 



Time to Complete 

 Northward Runs, 

 Minutes 



Time to Complete 

 Southward Runs, 

 Minutes 



Winds 



Waves 



In water 

 Out of water 



9.60 

 9.67 



8.58 

 8.57 



Neg. * 

 Neg. 



Neg. 

 Neg. 



Average time in the four tests : 



Maximum towing speed under 



zero current and wind conditions 



9.11 min 



: 6.6 knots 







*Negligible 



It may be seen from the table that the position of the propellers had no 

 noticeable effect upon the total drag created by the FTB. The presence 

 of current in the test area may also be noted from the difference in 

 time required to complete the test runs northwards and southwards . From 

 these measurements, the calculated value of the current's northward 

 component was approximately 1/4 knot. 



(ii) Flattop boat partially loaded: Based upon the observation that the 



position of the propellers did not affect the measurements, the 

 propellers were kept in the stored position in all subsequent tests in 

 this series. The partial FTB loading consisted of 300 ft each of both 

 Bennett booms and three men, totaling 2600 lb. There was no noticeable 

 wind but waves were estimated to be as high as 1 ft. 



The time required to complete the maximum speed run was 9.63 minutes 

 going north and 8.45 minutes going south. The average time corresponding 

 to no wind and no current conditions was assumed to be the average of the 

 two, or 9.04 minutes, yielding the maximum towing speed of about 6 .6 

 knots . 



(iii) Flattop boat with negligible load: The total load in this test 



consisted of five people, weighing a total of about 800 lb. Waves were 

 not significant but variable northerly winds of up to 8 knots were 

 present during these tests. The times required to complete the test 

 run going north was 7.45 minutes and going south was 6.41 minutes. The 

 average time corresponding to no wind and no current condition was 

 assumed to be the average of the two, or 6.93 minutes, yielding the 

 maximum towing speed of 8.7 knots. 



These results are plotted in Figure 16 to compare the effect of 

 load upon the maximum speed of the FTB. As would be expected, increasing 

 the load decreases the maximum speed in both the self propelled and 



18 



