Ship was discharging Arab Light, not loading.
Lightning would not cause a 123,000 dwt ship to move.
It had to be the wind,
possibly abetted by the practice of leaving the mooring winch brakes loose
to avoid adjusting the wires as the ship rises during discharge.
Constant tension winches might have made a big difference here.
One Greek source say vessel "moved 8 m from its original position
as mooring lines loosened".
Several sources cite poor weather.
ERC says 20 to 50T, ITOPF says 300T.
Master and CO fined.
According to ITOPF,
This ship was involved in a 50T spill in the Suez Canal in 1996,
blamed on "steering difficulties".