Back to Casualty List | Search The Casualty Database
Precis File
SHIP NAME: Mobil Pegasus KEY: NUM. ENTRIES: 2
source Groombridge
type A
volume NONE
material
dead 0
link

The Mobil Pegasus exploded in the South Atlantic on 21st June 1973 whilst changing ballast. 1C was being loaded with clean ballast. The pipeline ran through the double bottom and entered 1C facing upwards (rather than downwards onto the bottom plates). Although there were baffles, the tremendous in-rush of water (and consequential static) when the Chief Mate opened the 1C valve must have ignited the explosive mixture in the tank. The plating peeled backwards like a sardine can virtually the width of the ship folding back upon the main deck. The hole in the deck extended from the centre castle to the break of the focsle. Fortunately, although we had many injured, there were no deaths mainly because of a fine Polish Doctor on a communist polish cargo ship that came to our help -- long story.

The fire was extinguished by flooding the forward tanks. Vessel limped back to Dakar for temporary repairs, and thence to Lisbon escorted by tug at 5 knots.

Mobil Oil had carried out tests a year before (on the Mobil Pegasus!) and knew about the dangers of static - unfortunately they failed to tell the mariners at sea. I know this because by luck I came upon (2 years ago) the American who carried out the tests.


source CTX
type A
volume 0
material
dead 0
link

We have the above graphic account from Steve Groombridge who was a crew member at the time.

The 1969 built, non-inerted double bottom VLCC survived and was repaired. This was used as evidence in favor of double hulls in the OPA 90 debate. In fact, there is no reason to believe that the double bottom made any difference structurally one way or the other. The unusual piping arrangement was probably a factor but this could have been easily countered by inerting. The Mobil Pegasus explosion is not an argument against double bottoms. The Mobil Pegasus explosion is an argument for inerting.

In 1973, Mobil must have known about Shell's work on static electricity which was published in 1971.