On 06 August 2001, the M/T GENMAR CONSTANTINE was moored
and discharging its cargo at ATOFINA Dock 1
when the empty, outbound, M/T EAGLE CHARLOTTE passed the GENMAR CONSTANTINE.
The resulting hydrodynamic "surge" pulled the GENMAR from the dock
breaking three lines and three 12 inch transfer hoses filled with oil.
See Case No. 42566 for pollution details.
A marine casualty investigation was initiated by MSO Port Arthur
to look into this incident based on the documented reoccurring wake damage
occurring along the Sabine-Neches waterway.
The Sabine-Neches waterway is narrow ranging from 500 to 300 ft wide
with an average depth of 40 ft.
Deep draft vessel traffic along the waterway including some larger OSVs
create surge due to the displacement of passing vessels along the confined waterway.
In addition, the speed of vessels transiting the waterway
is an important contributing factor to the level of surge - the greater the speed the larger the surge.
Vessels in shallow water are impacted the most by this hydrodynamic phenomenon
for the same reasons that ocean waves break along the shoreline.
Deep draft vessel traffic along the waterway is managed locally by the Sabine Pilots.
A Coast Guard vessel traffic system (VTS) is currently not established
in the area to monitor the waterway.
A operating VTS in the area would be able to monitor vessel traffic speed
along the waterway without bias.
In relation to this ATOFINA spill involving two deep draft vessels,
the ATOFINA dock is in shallow water
which contributes to the surge effect in that area.
In addition, the ATOFINA dock is dated and was not originally designed
to accommodate today's larger deep draft vessels.
To help prevent the movement of vessels in their moorings,
good marine practice supports maintaining taught mooring lines
thus eliminating any slack in the lines
reducing the likelihood of synthetic snap-back
or catastrophic parting of mooring lines.
The incident on the morning of 06 August 2001 at the ATOFINA terminal Dock 1
is complex in nature and a number of contributing factors
led to the catastrophic failure of the lines holding the M/T GENMAR CONSTANTINE.
A few factors are addressed below:
1. The actual speed of the outbound EAGLE CHARLOTTE
cannot be determined accurately with the available evidence;
however, witness interviews and the EAGLE CHARLOTTE's Bridge Note Book,
place the speed of the vessel at 4 to 7 knots.
2. The effect of a passing deep draft vessel on the hydrodynamics
in the vicinity of ATOFINA Dock 1 are uncertain,
since there are no hydrodynamic models in the area for such activity.
Therefore, how the reported surge affected
the GENMAR CONSTANTINE are not completely certain.
3. What is certain is that the mooring lines for the GENMAR
CONSTANTINE had enough slack to allow all three 12 inch transfer hoses
to stretch to the point of being severed at the ship-to-hose coupling.
In conclusion, the outbound vessel has a responsibility
to travel at a safe speed and maintain vessel steerage
while also being responsible for the vessel's wake.
The moored vessel has a responsibility to maintain taught lines at all times.