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

S0300-A6-MAN-060Although effective, this replacement system has not proven to be a complete answer to smallspills. A NEESA study is underway to identify a new self-propelled, belt-operated skimmer vesselfor small spills. This skimmer will be procured by NEESA for NOSCDRs.5-4.3.2 NAVFAC Medium Skimmer. The Dynamic Inclined Plane (DIP) 2001 medium skimmeris no longer procured for NOSCDR use. The new small skimmer system discussed in the previousparagraph is intended to replace the medium skimmer. NOSCDRs will continue to use theDIP 2001 medium skimmers until they are no longer in inventory. The new skimmers procured byNEESA will eventually replace the medium skimmers.The DIP 2001 is a self-contained portable system that is moved by truck to the spill site.A DIP 2001, air compressor, skimmer-handling boom, 400-gallon storage tank and 200 feet ofcontainment boom are included in this system. The system is designed to move surface oil downthe underside of the inclined plane to an open area beneath the skimmer. Like the other DIP-operatedskimmers, the oil rises and fills the tank above the open area. The skimmer is moved in theoil manually with a control wand. The 22-foot-long wand also contains hose for pumping recoveredoil from the skimmer to the 400-gallon tank on the pier. A control box held on the pier orshore operates the skimmer systems and controls the belt speed.DIP 2001 systems are intended for small to medium spills occurring in harbors and other stillwater areas. The skimmer remains stationary and the oil is brought to the rotating inclined planewith an artificial or natural force. The apex of the skimmer and boom configuration is locateddownwind or downcurrent. The surface oil should flow into the skimmer mouth. Oil movementcan be enhanced with water and air jets, prop wash, pusher boats or firefighting monitors. Universalboom fittings allow boom to be added if the spill is larger than the area covered by the initial200 feet of boom.5-4.3.3 NAVFAC Large Skimmer. The DIP 3001 shown in Figure 5-18 is intended for mediumand large spills in open harbors. The operating principle for this skimmer is the same as the DIP2001. However, the DIP 3001 has a wider belt and, thus, a higher recovery rate. The DIP 3001 isa self-contained, 26-foot vessel, manned by a crew of two and capable of operating in three-footwaves. Open water operations are possible in good weather. The skimmer has two oil containmentsweeps that funnel oil toward the dynamic inclined plane. Water enhancement jets push oilinto the recovery plane. A debris rake in front of the inclined plane keeps out large pieces ofdebris. Smaller debris that ends up in the oil collection well is removed by a hydraulically operatedbasket system.Containment boom attached to the skimmer’s bow and towed by two vessels increases the sweepwidth and recovery rate. With the sweep boom attached, the skimmer-boom-towboat makeup ismaneuvered slowly through the oil spill by using a combination of boat and skimmer propulsion.Skillful manipulation of boats and skimmer keep oil flowing into the inclined plane mechanism.The DIP 3001 can recover up to 60 gallons per minute operating at one to two knots. Water percentagein the recovered oil is usually less than one percent. The on board storage capacity is1,500 gallons. Continuous recovery and offloading is possible if a bladder or barge is brought tothe skimmer.5-23