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Precis File
SHIP NAME: Mobiloil KEY: NUM. ENTRIES: 5
source LMIU
type C
volume
material
dead
link

Grounded 1 mile S of St Helens, Columbia River Mar 19 1984 Refloated. Sold Towed to Taiwan to be broken up.


source OSCH
type A
volume 3925B
material No 6 Fuel Oil
dead
link

The Tank Vessel Mobiloil, while en route from Ferndale, Washington to Portland, Oregon, suffered a steering failure at 0005 on March 19, 1984 which resulted in the grounding of the vessel near Warrior Rock in the Columbia River approximately 10 miles downstream from Portland, Oregon. Punctures and gashes ruptured the number 1-5 starboard cargo tanks releasing 3,925 barrels of heavy residual oil, industrial fuel oil, and No. 6 fuel oil. The vessel remained grounded perpendicular to the current until March 26, when it was refloated and escorted to dry dock in Portland. At the time of the spill the wind was from the south and the river current velocities were 1.5-3.0 knots. The incident occurred in a turbulent area of the river that experiences some tidal influence.

No. 6 fuel oil is a heavy product with an API gravity that ranges from 7 to 14. Spilled oil was distributed on the surface of the river, throughout the water column, and on the river bottom. The shoreline was not impacted as severely as anticipated. Areas thought to be thick oil were actually sheen. The only black oil observed on the surface occurred as small tar balls that were commonly found clinging to debris. The sinking nature of the oil made estimates of the spill size difficult. Initial Mobil and USCG estimates of 1,000 barrels were revised after additional information suggested that the majority of the oil had been incorporated into the water column and in the river bed.


source CAHILL_G
type D
volume 170000G
material Fuel Oil
dead
link

Ship was going upriver loaded at 92 RPM against a 4-6 mph current. Speed over the ground was about 12 knots. Helmsman appled 25 deg right rudder, but when he went to counter rudder, rudder failed to respond. Ship grounded at 0006. Turned out the clevis pin which connects the stroke crosshead to the spring assembly of the pump differential, was raised up above the crosshead link. The pump stroke was in the right full rudder position. A search was made for the missing cotter pin, but it could not be found.

Expansion trunk cover of 1S blew open, spewing oil on deck. Ullages revealed that the forepeak tank, and 1 thru 5 starboard wings had been ruptured. Crew started transfering oil but 170,000 gallons of 8.3 MM on board was spilled.


source ERC
type D
volume 571 MT
material No 6 Fuel Oil
dead
link

Grounding due to steering failure. Fined USD40,000.


source CTX
type A
volume 3925B
material F
dead 0
link

ETC puts this psill at 5000B. Osir says 168,000 gallons of No 6 heavy fuel oil. Hooke confirms loss of steering, says 150 ft of hull was holed, CTL.

The phenomenon of the cargo tanks venting on grounding was also observed in Valdez and Sea Empress. The sea bottom pushing into the tanks pushes the cargo upward.

The NTSB Investigation report is NTIS PB84-916409, but CTX has not yet seen.