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

S0300-A6-MAN-0604-3.2 Deployment Procedures. Deploying boom is a coordinated effort between boat operatorsand personnel aboard barges, skimmers or ashore. Efficiency in this evolution is gained throughregular team training. Procedures that help successful boom deployment are:• Assemble boom before launching or as the boom is hauled into the water. Attachingboom from small craft is dangerous, difficult and slow.• Launch boom into—not across current. Towboats should have sufficient power tomaintain headway into the current.• Moor booms at one end and stream them with the current.Most importantly, successful deployment of oil containment boom requires judicious use of commonsense. Every boom deployment is different because of geography, environmental conditionsand experience levels of people involved. Important ingredients for success are good seamanshipand small boat handling. Persons in charge should discuss the evolution with their people prior toactual deployment to achieve desired results and assure safety.4-4 BOOM MOORING SYSTEMSBoom mooring systems should keep the boom in place in the maximum current and tide in a specificarea. Boom cannot be expected to be effective at right angles to the current. Good boom systemdesign provides a method to slack the boom to an aspect more parallel than perpendicular tothe current during high-current periods.Oil spills in ports and other inland waterways are frequently close enough to the shore to allowone end of the boom to be anchored ashore. Several anchors secured to buoys and lines at regularintervals along the boom are necessary to eliminate the belly caused by the forces acting againstthe boom skirt and floats. Mooring systems should be laid out, assembled and tested before theyare needed. Ad hoc mooring systems improvised in the field have proven to have a low potentialfor success.4-4.1 Selecting Mooring Anchors. The anchor must secure the boom against wind- and currentgeneratedforces. The total force can be estimated by applying formulae for wind and currentforces and summing the results. Anchor holding power must be greater than the total force.Appendix E describes boom mooring calculations.Water depth and combined current and wind forces determine the anchor size and optimumanchor chain scope to keep the system in place. Buoys between the anchor chain or line and boomhelp maintain the correct aspect of the boom. The scopes of line from the boom tension member,buoy and anchor varies with the forces against the boom. Normally, scopes of at least five timesthe depth are needed. A shot of chain between the anchors and mooring line adds weight to themoor, increases bottom contact and friction and holds the anchor shank and pull on the anchorparallel to the bottom—all these increase the efficiency of the moor. A typical mooring leg isshown in Figure 4-14. Appendix G of the U.S. Naval Salvage Manual, Volume 1, S0300-A6-MAN-010, provides an in-depth discussion of anchor performance.4-22