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Re: Classic laker design

Posted: November 9, 2023, 5:43 pm
by Toronto Guest
Great post! Thanks for taking the time to explain.

Duluth Guest wrote: November 8, 2023, 12:03 pm Screen bulkheads are not screens in the traditional sense. Please, please don't envision them as such. This is possibly one of the most common peices of mis-information regarding the Edmund Fitzgerald that exists. A "screen bulkhead" refers to the design of the bulkhead and they are not actual screens. They are common in vessel construction and are used today still. The term "screen" refers to how the steel sheets that divide to holds are reinforced. Screen bulkheads have stiffeners that run vertically and horizontally intersecting each other at right angles like a screen, thus the name. They are the most robust design of bulkhead. Corrugated bulkheads are also used in vessel construction but are not as robust having less transverse rigidity. The AAA vessels also have screen bulkheads and were designed with 3 cargo holds as was the Arthur B. Homer and Herbert C. Jackson. Wilfred Sykes also has screen bulkheads as did Sparrows Point, Johnstown and Elton Hoyt 2nd ( Michipicoten today). I have attached an image of a screen bulkhead to help with the visualization of how they are constructed. The image is of the William A. Irvin. The Colonel James M. Schoonmaker is an example of a vessel that utlizes corrugated bulkheads and I have attached an image of her as well. I have also attached an image of Arthur Homer being lengthened that shows her screen bulkhead between cargo holds 2 and 3.

How many cargo holds and how many sumps a vessel has is specific to the design of the vessel. Keep in mind that vessels are not constructed like automobiles in that each is alike; they are each vastly customized according to how the shipping company intends to use it. Constructing a vessel is akin to erecting a building in that sense. Few buildings are identical and each is built for a specific purpose. The singular cargo hold sump feature of the Fitzgerald was not uncommon for vessels designed to haul taconite. Taconite pellets are like little iron marbles and allow water to pass through them very easily and the Fitzgerald and Homer were designed specifically to haul taconite. The bulkheads dividing the cargo holds were not water tight so the water would drain to the stern end of the #3 hold. Many of the vessels designed as straight deckers had doors through the bulkheads large enough drive a buldozer through. The Sykes for example as well as the William A. Irvin ( see attached). The bulkheads on forward end of hold 1 and the after end of hold 3, were water tight though. These separated the cargo hold from occupied machinery spaces. The John G. Munson, on the other hand was constructed to haul primarily limestone which is a cargo that doesn't drain nearly as efficiency as taconite does. Vessels that were designed to haul high grade ore, which is much finer grained, or other similar cargoes like sand, salt, gravel, coal and etc., typically have more sumps within the cargo holds simply because the material doesn't allow water to drain through it easily like taconite does.

Re: Classic laker design

Posted: November 8, 2023, 12:44 pm
by Guest
The Edmund Fitzgerald's design was typical for the 1950s. Nearly all the straight-deckers of that era had three cargo-hold with screen bulkheads between them. Ships that were lengthened in the 1970s either received another cargo hold, or the center cargo-hold was made larger.

The only thing that sets the Fitzgerald apart from the ones preceding her was that she had a greater amount of welding in her construction - though riveting was still used in the gunwale bar connection; i.e. deck strake / sheer strake.

Re: Classic laker design

Posted: November 8, 2023, 12:03 pm
by Duluth Guest
Screen bulkheads are not screens in the traditional sense. Please, please don't envision them as such. This is possibly one of the most common peices of mis-information regarding the Edmund Fitzgerald that exists. A "screen bulkhead" refers to the design of the bulkhead and they are not actual screens. They are common in vessel construction and are used today still. The term "screen" refers to how the steel sheets that divide to holds are reinforced. Screen bulkheads have stiffeners that run vertically and horizontally intersecting each other at right angles like a screen, thus the name. They are the most robust design of bulkhead. Corrugated bulkheads are also used in vessel construction but are not as robust having less transverse rigidity. The AAA vessels also have screen bulkheads and were designed with 3 cargo holds as was the Arthur B. Homer and Herbert C. Jackson. Wilfred Sykes also has screen bulkheads as did Sparrows Point, Johnstown and Elton Hoyt 2nd ( Michipicoten today). I have attached an image of a screen bulkhead to help with the visualization of how they are constructed. The image is of the William A. Irvin. The Colonel James M. Schoonmaker is an example of a vessel that utlizes corrugated bulkheads and I have attached an image of her as well. I have also attached an image of Arthur Homer being lengthened that shows her screen bulkhead between cargo holds 2 and 3.

How many cargo holds and how many sumps a vessel has is specific to the design of the vessel. Keep in mind that vessels are not constructed like automobiles in that each is alike; they are each vastly customized according to how the shipping company intends to use it. Constructing a vessel is akin to erecting a building in that sense. Few buildings are identical and each is built for a specific purpose. The singular cargo hold sump feature of the Fitzgerald was not uncommon for vessels designed to haul taconite. Taconite pellets are like little iron marbles and allow water to pass through them very easily and the Fitzgerald and Homer were designed specifically to haul taconite. The bulkheads dividing the cargo holds were not water tight so the water would drain to the stern end of the #3 hold. Many of the vessels designed as straight deckers had doors through the bulkheads large enough drive a buldozer through. The Sykes for example as well as the William A. Irvin ( see attached). The bulkheads on forward end of hold 1 and the after end of hold 3, were water tight though. These separated the cargo hold from occupied machinery spaces. The John G. Munson, on the other hand was constructed to haul primarily limestone which is a cargo that doesn't drain nearly as efficiency as taconite does. Vessels that were designed to haul high grade ore, which is much finer grained, or other similar cargoes like sand, salt, gravel, coal and etc., typically have more sumps within the cargo holds simply because the material doesn't allow water to drain through it easily like taconite does.

Re: Classic laker design

Posted: November 7, 2023, 6:29 pm
by Guest
Screens

Classic laker design

Posted: November 7, 2023, 4:54 pm
by Guest
I have read that the Fitz only had 3 compartments compared to most of her contemporaries. Does the Jackson, Homer and Obserstar (other late 1950s vessels) share this design? Also how many compartments did the AAA’s, Munson, Sykes, Hoyt and Lee A/Middletown have? I have also heard that the Fitz’s bulkheads were screen bulkheads, any other ships share this as well? This may have lead to the numerous accounts of stability/twisting problems with the ship, having less compartments and a less sturdy bulkhead. Also, I read that the Fitz only had one drain in the bottoms compared to many on other vessels. Anymore info on the Fitz or her contemporaries on this issue would be greatly appreciated.