U.S. Navy Ship Salvage Manual Volume 6 - Oil Spill Response

S0300-A6-MAN-0604-5 BOOM BEHAVIORFigure 4.14. SUPSALV Mooring System, Oil Boom Recovery System.Bad weather often makes a boom useless. Wind, waves, currents and ice all decrease boom effectiveness.Booms made ineffective by weather should be left in place whenever possible. An efficientboom remains perpendicular to the water surface. Changing the boom’s aspect reduces theforces affecting it and makes the boom partially effective until the weather subsides.The ability of a boom to retain oil depends on its size, profile and ability to conform to waves. Theways in which oil escapes a containment boom are shown in Figure 4-15. In addition, oil canescape through poor connections between boom sections.4-5.1 Current Effect on Boom. Oil entrainment or underflow occurs when the boom skirt is nolonger vertical; oil flows down the face of the skirt and under it as the current increases. Testsshow that boom subjected to perpendicular current entrains oil at about 0.7 knots. Figure 4-16shows maximum deployment angle to keep the component of current velocity perpendicular tothe boom skirt below 0.7 knots for different current speeds.4-23