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Precis File
SHIP NAME: OMI Charger KEY: NUM. ENTRIES: 3
source LMIU
type C
volume
material
dead 3
link

Explosions and fire while under repair in Galveston anchorage 09 Oct 1993 Fire extinguished 10 Oct Holed on port side and flooded Stern resting on bottom Refloated 19 Oct Arrived Port Arthur 14 Dec Towed out 17 Jul 1994. Two crew dead and one missing. Demolition commenced at Brownsville 01 Aug.


source USCG
type D
volume
material
dead 3
link http://www.uscg.mil/hq/g-m/moa/boards/omicharger.pdf

This is an unusually good USCG investigation report. Ship was US flag in gasoline trade between Houston and Tampa. Ship was repairing a leak between aft ballast tank and 5P cargo, when she exploded. Leak was discovered loading Houston, but they went to Tampa anyway, returned in ballast to do the repairs anchored inside Galveston Bay.

Despite the fact that she was fitted with inert gas, 5P was not inerted before purging. The tank was purged by ballasting up and then draining. In so doing the tank was overflowed through the tank lid, but the butterworth openings were not opened. This could have left some pockets of gasoline and gasoline vapors in the tank in the highest points of the tank. One calculation indicated that a 1.1 barrel wedge of gasoline could have existed at the top forward corner of the tank. The NTSB calculated that this would have been enough to put that tankover the LEL it it totally valporized. OMI consultants claimed that you would need 2 barrels of gasoline to do this. The report points out that 5S which had been purged in a similar manner blew up 2 hours later.

After the tank was drained to a level below the repair, the tank was closed up. and not subsequently tested. Nor was it inerted during welding from the other side. This was done to save a little off-hire time by allowing hose testing from the 5P immediately after completion of the job. [Also the IG would be dangerous to the repair team if it leaked into the ballast tank.]

This area of hull structure had a history of leaks. The ship had also just repaired two leaks between 5C and the pump room. In one case, they used a doubler [not Class legal] because as the Master said the bulkhead was too thin to gouge out.

The ship has just completed a docking and an ABS and USCG survey, two weeks earlier. During this docking, some side shell stiffeners were renewed in the aft port ballast tank. The ABS surveyor allowed the repair to be discontinous at the bulkhead with the new stiffeners terminating at a landing plate welded to the bulkhead. [This is contrary to Class rules]. It was a leak at one of the landing plates that was being repaired at the time of the explosion.

The USCG too some thickness measurements in the bulkhead. At the level of the landing plate the 11 mm bulkhead had on average wasted down to less than 6mm. Other measurements ranged from 22% to 47% wastage. The lading plate weld was badly undercut, reducing the bulkhead thickness by more than 70%.


source CTX
type D
volume
material
dead 3
link

NTSB report is NTIS PB94-916404, but CTX has not yet seen.

The USCG is critical of ballasting up to purge. But if it had been done properly, this should have worked, especially on a ship in the gasoline trade which means clean tanks. However, after doing the purge and draining, the tank was close up, not ventilated, and not tested. With the tank leaking into the aft ballast tank there would be a temptation to cheat on the ballasting in order to avoid putting too much water in the ballast tank. The USCG criticism of the failure to properly monitor the tank atmosphere is right on.

The USCG report has very little to say about the horrible wastage in the bulkhead (which had just passed Class and USCG survey). But in order for the 5P to explode the welder must have inadvertantly burned thru the bulkhead. With a bulkhead that in the area had pointa down to 4 mm or less, this was almost inevitable. CTX believes that this wastage was at least as important a cause of this casualty as the slightly sloppy purge.

shipspotting has some pictures of the mess labeled "stbd slop tank" but damage is clearly on the port side just forward of house. Lucky more people weren't killed.

It is interesting that somehow OMI had gotten the USCG to given the ship an exemption from Marpol (maybe OPA) allowing then to convert 2 and 4 wings to cargo. This does not appear to have had any effect on this casualty.