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

S0300-A6-MAN-060ondary booms used to divert oil as it moves with tide change. The boom and skimmers used topick up the diverted oil can be moved to continue recovery operations.4-3.1.4 Towed Boom. Boom is towed to collect oil for recovery or to funnel oil directly intoskimmers operating on the open water. Figure 4-12 shows how lengths of boom are towed in a U-shape by two boats to collect oil and bring it to skimmers or other recovery devices.Figure 4-12. Towed Boom.Sweeping or collector boom consists of sections of floating boom attached between an oil skimmerto a towing boat or boats. The boom directs the oil into the mouth of the skimmer for pickupor concentrates the oil in a small area where the skimmer operates. Paragraph 5-3.4 describesskimming and sweeping operations with towed boom. Long boom distances between skimmerand towboat allow great surface areas of water to be skimmed.4-3.1.5 Free Drift Containment. If boom cannot be moored because of current velocity or waterdepth, oil can be encircled by freely drifting boom to concentrate the oil for recovery. Drift rate ofthe boom and encircled oil can be slowed by attaching sea anchors or trailing chain in shallowwater.4-3.1.6 Multiple Setting. Oil can escape encircling or waylaying boom for a variety of reasons.Setting additional booms separated by 3 to 15 feet increases the amount of oil contained for subsequentrecovery.4-3.1.7 Deployment in Channels and Rivers. Oil can be kept from spreading in narrow channelsby laying boom at appropriate angles, depending on current velocity, as shown in Figure4-13. A limited opening can be left to permit vessel traffic.4-20