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

S0300-A6-MAN-0604-2.2.1 Fence Boom. Fence boom consists of a single sheet of material forming both freeboardand skirt; floats and ballast weights are attached at intervals rather than continuously as in solidflotation or inflatable boom. Fence boom requires less storage space than solid flotation boom andhas similar advantages. The main disadvantage of fence boom is that long spans of the boom tendto lay over in strong wind or current.4-2.2.2 Sinking Boom. Construction of sinking boom is similar to that of inflatable boom, but itis usually made in longer sections. Sinking boom is useful when oil containment systems wouldblock shipping traffic and have to be moved to allow ship passage. Heavy chain combination ballastand tension members hold the boom on the bottom when ships are passing. After the shippasses, the flotation cells are filled with air and the boom resurfaces to act as a barrier. In hightrafficareas, this type of boom can be permanently stored on the bottom and inflated when neededto contain an oil spill.4-2.2.3 Net Boom. Net boom is designed to allow water to pass through the barrier while capturingtar balls and viscous oils. The system stops some of the products from unimpeded spreadingand provides excellent containment in conjunction with conventional boom. Net boom is appropriatewhere products with low pour points are floating in waters subjected to excessive currents;most other types of boom lose effectiveness in currents above 1.5 knots.Figure 4-2. Anchored Net Boom.4-6