On April 19, 1979 the crude carrier Seatiger was alongside the Sun Oil
terminal at Nederland Texas.
The ship had completed cargo discharge and had started ballasting for sea.
However, a thunderstorm developed.
Fifteen minutes later the ship was struck by lightning
which ignited cargo vapour at the vent riser.
The flames traveled back to the cargo tanks.
Seatiger was rocked by a series of explosions which killed two crew members.
In this case, the ship's IGS was not used during discharge
as there were faults in the automatic tank gauging system.
Taking manual ullages would have caused some inconvenience.
Every cargo tank was seriously damaged by either explosions
or the fire that followed.
The damage was so severe that, had the incident occurred at sea,
the ship would almost certainly have jack-knifed and sunk within seconds.
As it was she merely settled into the mud, to become a total constructive loss.
This case is clear cut: the destruction of Seatiger
would not have happened if the IGS had been used,
However, to other factors contributed to disaster.
The P/V valve by-pass had been left open -- permitting
vapours to continue escaping and allowing a clear flame
passage to the tanks.
Even more importantly, the flame arrester had been fitted upside down
with gaps up to 1/8th of an inch around the edges.
This effectively destroyed the primary flame barrier.