by Guest » April 28, 2023, 5:27 pm
Ships built in the 1950s and 60s were based on strength standards that dated from the 1920s, when the 600 footers were the industry standard. But since the strength standard for that time didn't cover ships longer than 650 feet, it meant designers and marine architects had to extrapolate the strength table curves in order to cover the longer ships being built, i.e. 650+ feet. And since even longer ships were in the planning stages during the 1960s, the then existing strength standard was inadequate for the task.
The US Coast Guard, Department of Transport in Ottawa along with the Society of Naval Architects and Marine Engineers (SNAME) set up a committee to study changes in the strength standard and with that came about the change in load lines. Canada in 1984 accepted the Great Lakes Strength Standard as it was revised, but the US government has seen the Great Lakes Strength Standard as an evolving one, hence the reason why they still call it the Interim Great Lakes Strength Standard.
The Roger Blough and Stewart J. Cort and the ships of the 1970s and later are built under the revised strength standard.
Many ships received a loadline increase starting in the late 1960s and were revised several times into the 1970s as the regulations were changed.
When the Arthur M. Anderson departed Two Harbors on November 9, 1975 she had an aft draft of 25 feet 09 inches, which was below her winter draft of 25 feet 9 inches. Meaning that the Anderson had a freeboard of 10 feet, 11 inches on departure.
The Edmund Fitzgerald departed Superior with an aft draft of 27 feet 06 inches, which was below her allowable winter draft of 27 feet 9 inches. As a result the Fitzgerald has a freeboard of 11 feet 11 inches upon departure from Superior.
Since the Fitzgerald had a greater freeboard than the Anderson, then how come the later didn't have issues with leaking hatchcovers the Fitzgerald is alleged to have had? With less freeboard, the Anderson would have been more impacted by the large waves that afternoon and evening than the Fitzgerald - yet, except for a damaged starboard lifeboat, no other damage was reported.
Those ships that are claimed to be "overloaded" back in the 1970s, still load to the same drafts they were assigned in the early/mid-1970s. Yet no one claims they are "overloaded" today. Is it just perception that ships were overloaded back then?
Ships built in the 1950s and 60s were based on strength standards that dated from the 1920s, when the 600 footers were the industry standard. But since the strength standard for that time didn't cover ships longer than 650 feet, it meant designers and marine architects had to extrapolate the strength table curves in order to cover the longer ships being built, i.e. 650+ feet. And since even longer ships were in the planning stages during the 1960s, the then existing strength standard was inadequate for the task.
The US Coast Guard, Department of Transport in Ottawa along with the Society of Naval Architects and Marine Engineers (SNAME) set up a committee to study changes in the strength standard and with that came about the change in load lines. Canada in 1984 accepted the Great Lakes Strength Standard as it was revised, but the US government has seen the Great Lakes Strength Standard as an evolving one, hence the reason why they still call it the Interim Great Lakes Strength Standard.
The Roger Blough and Stewart J. Cort and the ships of the 1970s and later are built under the revised strength standard.
Many ships received a loadline increase starting in the late 1960s and were revised several times into the 1970s as the regulations were changed.
When the Arthur M. Anderson departed Two Harbors on November 9, 1975 she had an aft draft of 25 feet 09 inches, which was below her winter draft of 25 feet 9 inches. Meaning that the Anderson had a freeboard of 10 feet, 11 inches on departure.
The Edmund Fitzgerald departed Superior with an aft draft of 27 feet 06 inches, which was below her allowable winter draft of 27 feet 9 inches. As a result the Fitzgerald has a freeboard of 11 feet 11 inches upon departure from Superior.
Since the Fitzgerald had a greater freeboard than the Anderson, then how come the later didn't have issues with leaking hatchcovers the Fitzgerald is alleged to have had? With less freeboard, the Anderson would have been more impacted by the large waves that afternoon and evening than the Fitzgerald - yet, except for a damaged starboard lifeboat, no other damage was reported.
Those ships that are claimed to be "overloaded" back in the 1970s, still load to the same drafts they were assigned in the early/mid-1970s. Yet no one claims they are "overloaded" today. Is it just perception that ships were overloaded back then?