Never to forget: November 10, 1975

Remember the 29 crew of the Edmund Fitzgerald. Rest in peace.



NTSB Marine Accident Report NTSB-MAR-78-3

ABSTRACT

About 1915 EST., on November 10, 1975, the Great Lakes bulk cargo vessel SS EDMUND FITZGERALD, fully loaded with a cargo of taconite pellets, sank in eastern Lake Superior in position 46 59.91 N, 85 06.6’W, approximately 17 miles from the entrance to Whitefish Bay, Michigan. The ship was en route from Superior, WI, to Detroit, MI, and had been proceeding at a reduced speed in a severe storm. All the vessel’s 29 officers and crewmembers are missing and presumed dead. No distress call was heard by vessels or shore stations.

The Safety Board considered many factors during the investigation including stability, hull strength, operating practices, adequacy of weathertight closures, hatch cover strength, possible grounding, vessel design, loading practices, and weather forecasting.

The National Transportation Safety Board determines that the probable cause of this accident was the sudden massive flooding of the cargo hold due to the collapse of one or more hatch covers. Before the hatch covers collapsed, flooding into the ballast tanks and tunnel through topside damage and flooding into the cargo hold through non-weathertight hatch covers caused a reduction of freeboard and a list. The hydrostatic and hydrodynamic forces imposed on the hatch covers by heavy boarding seas at this reduced freeboard and with the list caused the hatch covers to collapse.
Contributing to the accident was the lack of transverse weathertight



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At 1900, the ANDERSON advised the FITZGERALD that she was 10 miles ahead and 1 to 1 1/2 miles to the left (east) of the ANDERSON’s heading flasher. At 1910, the ANDERSON advised the FITZGERALD of northbound traffic 9 miles ahead of her. In response to a question about her problems, the FITZGERALD replied, "We are holding our own."

This was the last radiotelephone conversation with the FITZGERALD. When the ANDERSON’s radarscope was checked about 1920, there was no radar contact with her. Visibility increased about this time and although lights on shore more than 20 miles away and lights of a northbound vessel 19 miles away could be seen, the FITZGERALD, which should have been approximately 10 miles away, was not visible.

Between 1920 and 2030, the ANDERSON tried calling the FITZGERALD on VHF-FM radiotelephone, but got no response. At 2032, the ANDERSON notified the Coast Guard that the FITZGERALD may have suffered a casualty.

Wreckage identified as that of the FITZGERALD was located in position 46 59.91 N’, 85 06.6’ W in 530 feet of water in eastern Lake Superior just north of the International Boundary in Canadian waters. This position correlates with the last position of the FITZGERALD as reported by the ANDERSON.

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The FITZGERALD was last inspected by the Coast Guard and the ABS on October 31, 1975. Four minor structural defects in way of the hatches were noted and the Coast Guard ordered these defects to be repaired before the 1976 shipping season. The structural defects consisted of: A 1-inch notch in the plate in way of hatch No. 13; a 1-inch gouge in the plate in way of hatch no. 15; a 10-inch crack in No. 16 hatch end girder; and a 1-inch crack at the intersection of No. 21 hatch coaming and hatch end girder. All four defects probably resulted from damage from off loading equipment and did not affect the strength of the hull girder.

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The log of the ANDERSON shows the following on November 10:
1. At 1350, just north of Michipicoten Island, the winds were northwest by west at 5 knots.
2. At 1445, west of Michipicoten Island, the winds were northwest at 42 knots.
3. At 1520, just south of Michipicoten Island, the winds were northwest at 43 knots.
4. At 1652, north east of Caribou Island, the winds were northwest at 52 knots.

The master of the ANDERSON testified that 10 or 12 miles north of Caribou Island, the seas were running 12 to 18 feet, and south of Caribou Island, the seas were running 18 to 25 feet. He further testified that he observed winds gusts of 70 or 75 knots.

A NWS meteorologist testified that before the FITZGERALD sank, the average sustained wind speed was 45 knots from the northwest for a period of 6 to 7 hours and that these conditions would produce waves with a significant height of 15 feet. He also testified that there are usually 4 or 5 intense storms on the Great Lakes during the fall to spring shipping seasons. A storm of the intensity of the one recorded on November 10 would not occur every year; however, more intense storms have been recorded on the Great Lakes.

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The wreckage lies approximately 17 miles northwest of Whitefish Point, Michigan. The wreckage consists of an upright bow section, an inverted stern section, and debris from a missing 200-foot midship portion. The bow section is 276 feet long, inclined 15 degrees to port from the upright,
extends from the stem to a location between hatches Nos. 8 and 9, and is buried in mud up to the 28-foot draft mark.

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Fire and boat drills conducted in good weather while the FITZGERALD was moored indicated that a conventional lifeboat could not be launched in less than 10 minutes. Testimony indicated that as much as 30 minutes would be required to launch a lifeboat in a seaway and that a lifeboat probably could not be launched successfully and boarded in the seaway experienced by the FITZGERALD at the time of her loss. Most witnesses felt that a Great Lakes vessel could be abandoned more successfully with an inflatable liferaft rather than with a lifeboat.

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no survivors were found and no bodies were recovered. Ontario Canadian Provincial Police conducted numerous shoreline searches. The total lifesaving equipment recovered was: 1 lifeboat, one-half of another lifeboat, 2 inflatable liferafts, and 21 lifejackets or lifejacket pieces.

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When the master of the FITZGERALD first reported topside damage to the vessel at 1530 on November 10, he stated he had a fence rail down, had lost two vents, and had "both" pumps going. Flooding was occurring in one or more ballast tanks, the tunnel or a combination of ballast tanks and the tunnel. At the same time, because of the severe sea conditions, water was entering the vessel’s cargo hold through nonweathertight hatch covers. Between 1530 and the sinking, the FITZGERALD’s deck was awash with green water. Since the sheer strake extended 15 3/8 inches above the weather deck for the entire length of the vessel at side, water would have been trapped on deck. The combined effect of the water in the ballast tanks, the tunnel, the cargo hold, and on deck would have decreased the vessel’s freeboard, permitted more water to enter the cargo hold, and increased any trim or list initiated by the ballast tank or tunnel flooding.

The Safety Board determined through its structural analysis of the hatch covers that the sea state, combined with the loss of freeboard and the trim caused by flooding, could have imposed sufficient hydrostatic loads to cause a hatch cover failure and collapse under static loading.

The Safety Board calculations assumed a wave height of 25 feet. This was based on the ANDERSON’s observations of significant wave heights from 18 to 25 feet. A significant wave height of 25 feet means that the average height of the one-third highest waves is 25 feet. The Safety Board also calculated that, by 1915 on November 10, sufficient water had entered the hull of the FITZGERALD to reduce its freeboard to near zero at hatch No. 1. With zero freeboard, a wave of 25 feet in height would yield a static head of 12.5 feet. This static head was sufficient to cause hatch cover failure. 46 CFR 45.145 required that hatch covers be designed assuming a minimum 4-foot head of water.

The quartering seas would cause a piling" effect in the area behind the forward deckhouse and thus increase the static head. Any stresses caused by the dynamic forces of the boarding seas would have added to the static stresses and would have accelerated the hatch cover failure.

The hatch cover failure would have been severe enough to allow rapid massive flooding of the cargo hold. Since there were no watertight bulkheads within the cargo hold, the flooding water would have progressed throughout the hold within minutes, causing the vessel to sink bow first to the bottom of the lake. Upon impact with the bottom, the midship portion disintegrated and the stern section rolled over, coming to rest upside down.
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A detailed analysis of the amount of water that could have entered the cargo holds through openings between the hatch covers and the hatch coamings of the FITZGERALD on November 10, 1975, was made by both the Coast Guard and the Safety Board. Both analyses show that the current hatch design used on Great Lakes vessels, such as the FITZGERALD, would have permitted significant amounts of water to enter the FITZGERALD’s cargo hold under the sea conditions encountered on November 10, 1975.
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Between 1700 and 1730, the master of the FITZGERALD told the AVAFORS that "I have a ‘bad list,’ I have lost both radars, and am taking heavy seas over the deck in one of the worst seas I have ever been in."
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Probable Cause

The National Transportation Safety Board determines that the probable cause of this accident was the sudden massive flooding of the cargo hold due to the collapse of one or more hatch covers. Before the hatch covers collapsed, flooding into the ballast tanks and tunnel through topside damage and flooding into the cargo hold through nonweathertight hatch covers caused a reduction of freeboard and a list. The hydrostatic and hydrodynamic forces imposed on the hatch covers by heavy boarding seas at this reduced freeboard and with the list caused the hatch covers to collapse.
Contributing to the accident was the lack of transverse watertight bulkheads in the cargo hold and the reduction of freeboard authorized by the 1969, 1971, and 1973 amendments to the Great Lakes Load Line Regulations.