SamSam said:
.... A Coast Guard report suggesting that the hatches had not been closed properly was rejected..... The improperly latched hatch theory pissed off the families in its implication of negligence, incompetence, etc....
The National Transportation Safety Board doesn't insist on the improperly latched hatch theory, but it states:
"The Safety Board analyzed the structure of the FITZGERALD’s hatch covers to determine the forces necessary to cause their failure. The analysis assessed several possible failure modes and several possible draft conditions caused by flooding of either the cargo hold, the tunnel, or the ballast tanks. The results of the analysis indicated that boarding seas could have induced sufficient stresses to cause the catastrophic failure of one or more of the hatch covers when the FITZGERALD’s freeboard was reduced by the flooding. The resulting catastrophic structural failure would have allowed rapid massive flooding of the cargo hold."
Also:
"Because of the weather conditions following the sinking of the FITZGERALD and because the wreckage was lying on the bottom of Lake Superior in 530 feet of water, a comprehensive examination of the damage to the FITZGERALD was not undertaken until May 1976. At that time, a task force was formed, including representatives from the Coast Guard Marine Board of Investigation, the National Transportation Safety Board, the U.S. Navy Supervisor of Salvage, the Naval Undersea Center, and Seaward, Inc. of Falls Church, Virginia, an engineering consultant firm under contract to the U.S. Navy Supervisor of Salvage to make a visual survey of the wreckage using the USN CURV III System under contract to the USCG. The CURV III is an unmanned, deep-diving vehicle controlled from the surface and capable of television and still photography. This vehicle made 12 dives with a total of 56 hours 5 minutes bottom time and recorded 43,255 feet of videotape and 985 still color photographs."
And:
"There was extensive damage to the forward deckhouse and there were several holes in the bow shell plating. The rest of the shell plating extending back to the rupture was intact. The No. 1 hatch cover was entirely inside the No. 1 hatch and showed indications of buckling from external loading. Sections of the coaming in way of the No. 1 hatch were fractured and buckled inward. The No. 2 hatch cover was missing and the coaming on the No. 2 hatch was fractured and buckled. Hatches Nos. 3 and 4 were covered with mud; however, one corner of hatch cover No. 3 could be seen in place. Hatch cover No. 5 was missing. A series of 16 consecutive hatch cover clamps were observed on the No. 5 hatch coaming. Of this series, the first and eighth were distorted or broken. All of the 14 other clamps were undamaged and in the open position. The No. 6 hatch was open and a hatch cover was standing on end vertically in the hatch. The hatch covers were missing from hatches Nos. 7 and 8 and both coamings were fractured and severely distorted. The bow section abruptly ended just aft of hatch No. 8 and the deck plating was ripped up from the separation to the forward end of hatch No. 7."
Finally:
"Safety Board investigators considered the possibility that flooding resulted from a grounding which ruptured the hull plating in the area of some ballast tanks, but rejected this possibility for the following reasons:
A reconstruction of the FITZGERALD’s most probable trackline shows her path to be about 3 miles from the nearest position where grounding could have occurred.
No gouges, scraps, fractures, indentations, or other indications of grounding were visible on the exposed bottom plating on the after section of the wreckage. These observations were made during a close examination of the exposed bottom plating by underwater television from the CURV III. Damage to the bottom plating of a vessel from grounding on boulders in the rocky shoal north of Caribou Island during the severe sea conditions would probably have extended into the bottom plating of the stern section.
The FITZGERALD’s full speed was reported to be 16.3 mph. At this speed, it was impossible for the FITZGERALD to pass through her 1520 position, as determined by the ANDERSON from radar observations, and reach the nearest position at which grounding could occur by 1530. Although the list was not reported until 1530, the Safety Board concludes that topside damage occurred before 1520 and that the list was caused by flooding through the topside damage for a period of time. Even if massive damage could have been sustained at 1530 and instantaneous flooding could have occurred, it is unlikely that the FITZGERALD would have instantly reported the damage. If an immediate report had been made it probably would have mentioned damage more serious than just a list, the loss of a rail, and damage to the vents."
Cheers