8. To encircle a spill in an open area, care should be taken to ensure 

 that one end of the boom has a female end connector whereas the other 

 end of the boom has a male end connector. 



9. Several different adapters should be stored at the base to cater 

 to all possible eventualities. 



Best Size Mooring System for 1,000 ft of 36-inch Boom 



To determine the best size mooring system for 1,000 ft of 36-inch 

 boom under the conditions given in reference 14 (winds: 25 knots; waves: 



1 ft (height of the l/3rd highest waves) current: 2 knots), the procedure 

 given in reference 15 was used to calculate the maximum force on the boom 

 in a catenary configuration with a 65 percent opening. Using a freeboard 

 of 12 inches and a skirt depth of 24 inches, the maximum force that the 

 boom may exert on the two mooring systems is approximately 32,000 lb, or 

 16,000 lb on each of the two mooring systems. 



As noted earlier, the large mooring system evaluated in this test 

 program will hold approximately 5,500 lb in a sandy seafloor, but as little 

 as 790 lb in a clay or silty seafloor. It was, therefore, felt necessary 

 to select the largest available mooring system that can be handled by two 

 men, without mechanical equipment, in rough weather. An anchor to hold 

 16,000 lb in a harbor is felt to be too heavy for two men to deploy or 

 retrieve from the.FTB without the use of a winch. Instead, it was assumed 

 that an 80-lb Danforth anchor attached to a 10~ft long, 3/4-inch link 

 chain is about the maximum weight two men could deploy and retrieve from 

 a FTB in rough weather. 



Assuming further that (a) the harbor has a sandy seafloor, (b) the 

 water depth does not exceed 50 ft, (c) the link chain provides weight to 

 the mooring line to help set the anchor initially, but it does not help in 



' reducing the angle of the mooring line with the horizontal , and (d) a 

 420-ft length of 1-1/8-inch-diameter nylon mooring line is used, the 

 holding power of the 80-lb anchor, in a sandy seafloor, of 10,000 lb, 

 reference 12, may be reduced by about 16 percent tp approximately 8,400 

 lb. Whenever the current and wind conditions cause a drag exceeding 

 about 8,400 lb on each of the two anchors holding the 1,000- ft boom in 

 a catenary, the anchors will begin to drift slowly. In a harbor with a 

 sandy seafloor, the two 80-lb anchors could hold the boom in position 

 when the current is approximately 1.2 knots and winds are negligible, or 



.when the current is approximately 1.0 knot under 25-knot winds. If the 

 seafloor is clay or silty, however, the holding power of the 80-lb 

 anchor may be reduced to as low as 1,200 lb. Once this load is exceeded, 

 the anchor can "ball up", become clogged, and after it has come out, will 

 not penetrate again unless cleaned of the clog. 



If heavier mooring systems are desired to withstand currents up to 



2 knots under 25-knot winds, or if a clay seafloor is anticipated, then 

 it will be necessary to select heavier anchors and link chains, requiring 



32 



