decided to conduct this test while pulling from the transom instead of 

 the samson post. 



The second towing attempt was carried out from the transom using 

 a bridle assembly. The winds were light and variable, waves were less 

 than 6 inches , and the ground swell was of the order of 1 ft . 



For the test, the tow line had a shackle connected to a Newco 

 thimble in the bridle, which permitted the bridle to slide freely. This 

 arrangement prevented the transom submergence at maximiom throttle . 

 However, several problems were noted. 



a. The bridle kept hitting the engine during turning. 



b. The turning radius of the UTB was larger compared 

 to towing from the samson post. 



c. The maneuverability of the UTB was greatly reduced. 



It was felt that towing from the samson post would be much better, 

 and further improvements could be obtained if: 



a. The height of the post were reduced, 



b. The fairlead were replaced by a guardrail located near the 

 engine, as shown in Figure 12. 



c. The height of the transom were increased and engines 

 with extra long shafts were used. 



During the entire catenary tow, both engines were maintained at 

 full throttle, a distance between the two UTBs of approximately 600 ft 

 was maintained, and each UTB was towing one end of the 900-ft boom 

 approximately 50 ft behind its transom, as compared to 150 ft recommended 

 in reference 8. The distance of 600 ft between the two UTBs was maintained 

 only visually, as no accurate measurement was felt feasible. 



The test run was made over a measured distance of 0.367 nautical 

 miles. Two tests were carried out while travelling north and two tests 

 were carried out while travelling south. The north test runs took 

 2 5.41 minutes and 24.11 minutes, for an average of 24.76 minutes. The 

 south test runs took 16.25 minutes and 15.90 minutes, for an average 

 of 16.08 minutes. Therefore, the average time required to complete 

 the test was calculated to be 20.42 minutes for negligible currents and 

 winds, yielding a maximum speed of 1.08 knots. 



Towing oil storage bag: Towing tests were conducted on the Kepner Sea 

 Container flexible oil storage bag. The bag is fabricated from 

 vinyl-coated nylon, has a nominal capacity of 2500 gal, and has a 

 dry weight of 240 lb. When full, the bag is 3 ft long, 5 ft wide, 

 and 4.5 ft high. The bag was towed behind the transom from the samson 

 post. The boat maneuvered well during this tow, with the bag both 

 fishtailing as well as porpoising. 



11 



