Maximum Speed of the Flattop Boat Under Own Power 



(i) Carrying the maximum load : The FTB loaded with the 900-ft boom and 

 five men, a total estimated load of 4350 lb, was run on a straight, 

 measured distance of one nautical mile on its own power at maximum 

 throttle on both engines. To minimize errors in measurement due to 

 currents and winds , each north test run was immediately followed by a 

 south test run, and the mean time was taken to be representative of the 

 actual time the FTB would have required in the absence of winds and 

 currents . 



These tests were carried out under calm conditions with negligible 

 winds and waves . The FTB was found to be stable and buoyant during the 

 test. The time to travel one nautical mile northward was 3.83 minutes, 

 and the time to travel the same distance southward was 3.63 minutes. The 

 average time was, therefore, 3.73 minutes, yielding a maximum speed of 

 the FTB of approximately 16 knots . 



(ii) Carrying a partial load: The partial load selected for this test 

 consisted of 300 ft each of the two Bennett booms, and three men, for a 

 total load of approximately 2600 lb. The winds were negligible but waves 

 were approximately 1-ft high. The time to travel one nautical mile 

 northward was 3.53 minutes whereas the time required to travel the same 

 distance southward was 3.27 minutes. The average time was, therefore, 

 3.4 m.inutes , yielding a maximum speed of approximately 17.6 knots. 



(iii) Carrying negligible loads: The last series of test runs under the 

 FTB ' s own power was conducted with no boom on deck but with five people 

 on board (approximate weight: 800 lb) . Under negligible winds and waves, 

 the time required to travel one nautical mile northward was 2.77 minutes, 

 and for the same distance southward it was 2.75 minutes. The average time 

 of 2.76 minutes yielded a m.aximum speed of approximately 21.7 knots. 

 These results are plotted in Figure 16 for comparison. 



Maximum Speed when Towed by a Utility Boat 



To complete these tests, the FTB was towed astern by a UTB, as 

 recommended in reference 8, with maximum throttle on the UTB's 85 hp 

 engine. The towing line of the UTB was tied to the samson post at one 

 end, through the fairlead, and then to the pad-eye on the center hull 

 of the FTB. A distance between the transom of the UTB and the bow of 

 the FTB of approximately 50 ft was maintained in these tests. A total 

 of three different loading levels on the FTB were tested over a 

 measured distance of one nautical mile, both going north and going 

 south. In each test, a crew of three people was used in the UTB. 



(i) Flattop boat fully loaded: For these tests, the FTB was loaded with 

 900 ft of boom and five men, with a total load of 4350 lb. Two 

 positions of the FTB propeller were tested to determine the difference 

 in speeds, if any. For the first test, the propellers were pulled up 



17 



