The National Transportation Safety Board has
released its report on a November 25, 2021 incident involving a 754-foot-long,
106-foot-wide LPG carrier, the Gas Ares, that led to more than $1 million in
damages. The vessel was transiting upbound on the Neches River in Port Neches,
Texas, when it struck the outermost of two harbor tugs moored alongside the no.
1 loading dock at the Motiva Port Neches Terminal. The tug Sabine was
outboard on the channel side with the tug Florida moored
inboard and alongside the dock, both facing up river.
- The Sabine sustained
damage to its starboard main engine/generator stack plating, anchor
handling boom, onboard image recording system, and about 11 feet of its
starboard bulwarks and starboard rubber fendering. The cost of repairs was about $34,000.
- The Florida sustained
damage to its no. 2 port wing fuel tank and starboard-side shell plating
near the engine room. The cost of repairs was about $56,000.
- The Motiva no. 1 dock
sustained damage to its pilings, steel beams that supported the concrete
deck, the concrete surface, and mooring dolphins.2 The cost of repairs was
estimated to be $967,000.
At the time of the incident, the Gas
Ares was under the navigational control of a state licensed pilot from
the Sabine Pilots.
ANALYSIS
Following is the NTSB report’s analysis of the
incident:
“As the 106-foot-wide Gas Ares was
transiting through the Neches River at half ahead at 8.1 knots, at 2208, the
pilot of the Gas Ares hailed the outbound 688-foot-long tow Chad
Douglas and proposed a starboard-to-starboard passing. Setting the
vessel up to meet the tow, the pilot of the Gas Ares favored
the left (south) part of the 400-foot-wide navigation channel—the same side
where vessels were moored at the Huntsman and Motiva docks. At 2212, about 4
minutes after arranging the passing, the pilot ordered the Gas Ares to
dead slow ahead to avoid making a wake as the LPG carrier passed a pipeline
removal project (to starboard outside of the navigation channel), and about 6
minutes later, the vessel was only making about 3.8 knots. The pilot’s decision
to order the vessel’s speed reduced in anticipation of passing the pipeline
removal project was what initiated the eventual collision with the Sabine at
the Motiva no. 1 dock.
“As the Gas Ares approached the
Huntsman dock (where an ATB was moored), Motiva dock no. 2 (where the
144-foot-wide tanker Wonder Polaris was moored), and the Chad
Douglas tow, the pilot faced a close-quarters passing with the vessels
moored at each dock. The pilot had the tug Hayley Moran—which had
been made fast to the stern of the Gas Ares—pull the Gas
Ares’s stern to starboard to keep it from falling onto the Wonder
Polaris. At the same time, she issued rudder and engine orders intended to
keep the LPG carrier from falling farther south and point its bow back into the
channel. North-northwesterly winds at 18–27 knots exerted pressure on the
exposed (in-ballast) starboard-side hull above the waterline (the 0.4-knot
current likely had little impact on the immersed portion of the hull). Thus,
the vessel—which was already on the left side of the narrow channel for the passing
arrangement with the Chad Douglas tow—was set farther toward
the left and the Huntsman and Motiva docks. With the pilot’s ordered reduction
of the ship’s speed, the Gas Ares’s rudder became less effective,
and the pilot was not able to move the vessel to starboard and away from the
nearby moored vessels by rudder and engine alone. The pilot’s efforts to use
the stern tug to pull the Gas Ares’s stern back to starboard and
the center of the channel caused the LPG carrier’s bow to point more toward the
left side of the channel and moored vessels. Without enough headway, the pilot
was unable to steer the vessel back to the center of the channel and avoid
striking the moored Sabine at the Motiva no. 1 dock.”
PROBABLE CAUSE
The National Transportation Safety Board
determines that the probable cause of the collision between the liquefied
petroleum gas carrier Gas Ares and the tug Sabine,
moored alongside the tug Florida at the Motiva Port Neches
Terminal no. 1 loading dock, was the pilot’s decision to reduce the vessel’s
speed in order to create less wake when passing a pipeline removal project,
causing a loss of rudder effectiveness in strong crosswinds that set the
carrier toward moored vessels.
- As always, there’s very much more in the full NTSB report.
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