At 19:32 on 18 November 1999, while the 56,115 gross tonnage tanker Alfa Britannia
was berthing at the North Stage of Tranmere oil terminal in the River Mersey,
a mooring line parted.
The mooring line then whiplashed and struck the gig-boat Osprey,
causing various injuries to all of her four crew members.
Liverpool Coastguard informed the MAIB of the accident at 20:48 that day.
The tanker was delivering a cargo of crude oil to the terminal
and was berthing at the stage, which had a number of dolphins (mooring platforms).
The first line forward was a breast line,
which was taken to dolphin No8 by Osprey and her crew.
The wire line had an 11m long nylon tail,
the eye of which was placed over a bollard on the dolphin.
The mooring line was heaved in by the ship''s crew and made fast.
When the gig-boat was taking the second mooring line by the ship''s side,
the first mooring parted.
The whiplash caused the line to hit the gig-boat,
resulting in injuries to the crew and one in particular,
who suffered multiple injuries.
Another crew member was thrown into the river
but was rescued by Osprey in difficult circumstances.
Two different test-houses examined the nylon tail
and found that dynamic loading had caused it to part.
The load imposed on the tail originated from the movement of the ship as
she finally came alongside.
The pilot''s intended instruction to the master had been
for him not to make the breast lines fast
before the ship was in her final position alongside.
However, there is conflicting evidence
between what the pilot thought he had instructed
and what the master thought the pilot had instructed.
The master thought the pilot had instructed him to keep the
first breast line tight, and he ordered the chief officer,
who was in charge of the forward mooring party, to do so.
Because all verbal communications were in Korean, the pilot did not know
whether his intended instruction had been passed properly,
or at all, to the chief officer.
The accident was caused by a breakdown in communications
between the pilot and the ship''s officers
in that his intended instruction not to make the breast line fast was not carried out.
Recommendations are made to Shell UK Oil Products Limited
on producing mooring guidelines,
specific to the operational requirements and conditions for Tranmere oil terminal,
and specific mooring plans for each ship.