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DNV discounted this theory for a number of reasons. First, under this
theory, someone on the bridge would have had to activate the BSR normal close
function from the toolpusher’s control panel or the driller’s control panel. DNV
concluded that no witness testimony supported this. Second, DNV pointed to
the testimony of Chris Pleasant, the Transocean subsea engineer, who testified
that the BSR was in an “open” state when he arrived at the bridge at
approximately 9:56 p.m. This was further evidence that no one had activated the
“close” function.

The second theory advanced was referred to as the “double clutch”
theory, which posited that the solenoid of the ROV supplied just enough
pressure to the hydraulic port on the BOP to cause the BSR to go only partially
356
into the wellbore. The Cameron representative described this as follows:

Also, there were at least a handful of cases during the course of the
intervention in which the shear rams were double clutched. In other
words, pressure was applied to the BOP and then it was relieved. It was
applied and relieved. There were at least a handful of times in which that
357
happened. . .

DNV concluded that “[t]he overall contribution of this ‘double clutching’
phenomenon cannot in DNV’s opinion be of significance compared to the
contribution of the trapped pipe between the ram blocks.”
358

J. Studies Evaluating the Reliability of BOPs

Within the last decade, MMS, through its Technology Assessment and
Research Program (“TA&R”), funded or co‐funded various studies regarding the
reliability of BOP systems in deepwater applications, shear ram capabilities, and
the evaluation of secondary intervention methods in well control. Some of
359
these studies pointed out deficiencies in BOP systems and made suggestions to
change MMS regulations and/or industry standards.

356 The ROV has a robotic arm that fits into a hydraulic port on the BOP stack to pump hydraulic
fluid into the BOP to close the ram blocks.
357 McWhorter testimony at 145.
358 Addendum to the DNV Report, at 10.
359 The TA&R Program supports research associated with operational safety, pollution prevention
and oil spill response and clean up activities.

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