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

Chapter 5: Operations
Figure 5-14. Concept of sideways motion of OSV to help concentrate oil
which allows quick derigging to allow for rapid travel to a new site.
5-3.4 Performance / Results
Concentrate SUPSALV’s Vessel of Opportunity Skimmer Systems were highly effective in
collecting pooled surface oil. The three ships collected a total of 21,176 barrels of oil during the
operation. The OSV’s proved to be very capable as well. They stored the recovered product in
internal mud tanks and decanted water off the bottom reducing the product to just oil. The oil
was transferred at sea to barges positioned in the Mississippi Canyon operating area reducing
the amount of time transiting away from the pooled oil. The SUPSALV team believed that they
were as effective in collecting oil as any of the vessels employed at the well head and
significantly more oil could be been collected if they had been allowed access to the thick
patches of oil (in place of other less capable vessels). Additionally, real time aerial spotting with
direct communication to skimming forces would have further increased productivity. Graphs of
total oil recovered and average oil recovered are included in Chapter 6.
When the ships had relatively calm conditions, oil could be herded and collected. In rougher
conditions, oil could be herded effectively but the weir pumps would pump a greater percentage
of water than in calm conditions. Beyond sea state 3 the skimmer systems were hoisted out of
the water to reduce the potential for damage.
The Paravane, a relatively new component in the VOSS systems, proved to be easier to deploy
than the outrigger and gave the ship more options while maneuvering. As a result, the paravane
is being included as a permanent addition to the High Speed Current Buster package. The
outrigger floats, constructed of rubber, quickly deteriorated in the oily environment. As an
upgrade, new aluminum floats have been specified to replace the rubber ones.
The MARCO Class XI Skimmer, while reliable and durable (standard 42” boom and hard
components) was not as effective as the High Speed Current Buster. It did not handle higher
seas as well and the heavy nature of the Class XI skimmer (4,300 lbs) made handling it in a
seaway more problematic. SUPSALV has indicated that the Class XI system will be phased out
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