U.S. NAVY SALVAGE REPORT DEEPWATER HORIZON ... - ESSM

Deepwater Horizon Oil Spill Response
skimmer system and their tendency to request employment in a manner incompatible with the
system’s capability. It was expected the MARCO systems could be moved around and
reassigned great distances from their base of operations. In reality, these vessels move very
slowly and traveling great distances exceeded what a skimmer could accomplish in a day and
afforded no opportunity for crew rest. On 15 June a vessel assigned to the Pensacola’s Task
Force 3 was moved by inexperienced tow boat operators without the ESSM skimmer crew
aboard. The maneuvering resulted in capsizing the skimmer and placing it out of commission for
the remainder of the operation. After that event, the SUPSALV team prepared a Concept of
Operations (CONOPS) guide for MARCO Class V skimmers which explained the capabilities and
limitations of the systems. Once ICS managers were provided these operations guide, a better
understanding of their employment was achieved. A copy of the CONOPS guide is provided in
Appendix A. A more detailed list of MARCO skimmer operational issues and observations is
provided in the DWH Lessons Learned document, Chapter 7.
5-3 Open Ocean Skimming
5-3.1 Systems Used
SUPSALV deployed two types of Vessel of Opportunity Skimmer Systems (VOSS) to the Gulf of
Mexico. Five total systems were deployed, four NOFI High Speed Current Busters and one
MARCO Class XI skimmer system. A basic description of these systems follows:
MARCO Class XI System Sorbent Belt Oil Skimmer System. The MARCO Class XI consists of a
filterbelt module, an induction pump, a squeeze roller assembly, and an offloading pump. The
skimmer assembly is designed to be towed through spilled oil and pick up the water and oil
emulsion. As the mixture flows up the filterbelt, the oil and water separate. The water passes
through the belt while the oil and debris continues on. A scraper located at the top of the belt
scrapes off solid debris and heavy oil, while the oil entrained in the belt is forced out by a
squeeze roller. The oil then drips into a hopper, where it is eventually pumped to a support ship
or other vessel by the offloading pump. Other major components include components include:
two 55’ sections of standard 42” boom to herd the oil toward the skimmer belt, an outrigger
assembly for separating the outboard end of the boom from the hull of the ship, a hydraulic
power module to provide hydraulic power for the skimmer and pumps and a knuckle boom crane
used to lift and maneuver the system components.
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