Major B
SOC-14 1K
Update
I have been working on the Liberty Ship design in some bits of spare time and have enough for an update.
The connections for all of the subhulls have been making my brain hurt but I think I have a solution now. First, let me describe the problem and I'll try to use pictures since I understand pictures better than paragraphs.
T5.09 on page 305 specifies that either grapples or connectors are required to attach subhulls. Grapples cost 1 ton and MCr 1 and allow detaching the subhull. Connectors are permanent and require half the tonnage but the same price.
I decided to use 200 ton modules for the Liberty so I thought I would use connectors for the main hull and grapples for the detachable subhulls. As I decided on an arrangement of the subhulls into 7 segments of 8 subhulls each I began to see that more connectors and grapples thatn I first estimated would be needed but I did not see the full scope of the problem yet.
for those of you better in math that already intuited the problem, I'll apologize in advance but I want to walk through the problem for math rocks like me.
Linking 2 subhulls is easy - 6 grapples each and they are attached to create a 400 ton "whole":
However, if you want to attach two of those 400 ton "wholes" side by side you need double the connections, so rather than 6 grapples you need 12:
So, looking at this image, the centerline vertical gap in the lower diagram will require not 18 connectors and/or grapples but instead 24 because you are connecting two 800-ton objects. Attaching 71 to 72 requires 6, attaching 74 to 75 requires 6 more, and attaching 77 to 78 requires 6 more for a total of 18 but because 73 is attached to 74 it requires you to add 6 more grapples or connectors along the centerline for a total of 24:
And those are just the links within a segment. When you link those segments together along the length of the ship, the requirements become even more onerous. Between segments 7 and 6 the total number of grapples and connectors require 42 tons and MCr 48. The segment 6 to 5 links are twice that, 84 tons and MCr 96, and the segment 5 to 4 links are thrice that, 126 tons and MCr 144.
All together, the links needed to assemble the hull I envisioned for the Liberty would require 1,152 tons and MCr 1,296 just for connectors between the subhulls. That is 10.3% of the total hull volume and an addition of 4.3% to the total cost of the hull, both of which seem excessive and inefficient. After all, shouldn't all or at least part of this be assumed when you purchase a braced cluster hull?
And that is my (for now at least partial) solution - I am going to assume that the main hull is enclosed within a framework of girders and bracing that eliminates the need for connections between the modules of the 4,000-ton main hull. Something like what I have illustrated in this view which eliminates the need for all main hull connectors and requires only 6 grapples to connect each subhull to the main hull along with 18 grapples in each portion of the main hull forward of segment 7:
The result is a reduction in grapple costs to 432 tons (3.9% of the total hull) and MCr 432.
I have not decided if this framework should be in addition to the cost of the braced cluster hull or if it should be included. Any feedback on that?
I have been working on the Liberty Ship design in some bits of spare time and have enough for an update.
The connections for all of the subhulls have been making my brain hurt but I think I have a solution now. First, let me describe the problem and I'll try to use pictures since I understand pictures better than paragraphs.
T5.09 on page 305 specifies that either grapples or connectors are required to attach subhulls. Grapples cost 1 ton and MCr 1 and allow detaching the subhull. Connectors are permanent and require half the tonnage but the same price.
I decided to use 200 ton modules for the Liberty so I thought I would use connectors for the main hull and grapples for the detachable subhulls. As I decided on an arrangement of the subhulls into 7 segments of 8 subhulls each I began to see that more connectors and grapples thatn I first estimated would be needed but I did not see the full scope of the problem yet.
for those of you better in math that already intuited the problem, I'll apologize in advance but I want to walk through the problem for math rocks like me.
Linking 2 subhulls is easy - 6 grapples each and they are attached to create a 400 ton "whole":
However, if you want to attach two of those 400 ton "wholes" side by side you need double the connections, so rather than 6 grapples you need 12:
So, looking at this image, the centerline vertical gap in the lower diagram will require not 18 connectors and/or grapples but instead 24 because you are connecting two 800-ton objects. Attaching 71 to 72 requires 6, attaching 74 to 75 requires 6 more, and attaching 77 to 78 requires 6 more for a total of 18 but because 73 is attached to 74 it requires you to add 6 more grapples or connectors along the centerline for a total of 24:
And those are just the links within a segment. When you link those segments together along the length of the ship, the requirements become even more onerous. Between segments 7 and 6 the total number of grapples and connectors require 42 tons and MCr 48. The segment 6 to 5 links are twice that, 84 tons and MCr 96, and the segment 5 to 4 links are thrice that, 126 tons and MCr 144.
All together, the links needed to assemble the hull I envisioned for the Liberty would require 1,152 tons and MCr 1,296 just for connectors between the subhulls. That is 10.3% of the total hull volume and an addition of 4.3% to the total cost of the hull, both of which seem excessive and inefficient. After all, shouldn't all or at least part of this be assumed when you purchase a braced cluster hull?
And that is my (for now at least partial) solution - I am going to assume that the main hull is enclosed within a framework of girders and bracing that eliminates the need for connections between the modules of the 4,000-ton main hull. Something like what I have illustrated in this view which eliminates the need for all main hull connectors and requires only 6 grapples to connect each subhull to the main hull along with 18 grapples in each portion of the main hull forward of segment 7:
The result is a reduction in grapple costs to 432 tons (3.9% of the total hull) and MCr 432.
I have not decided if this framework should be in addition to the cost of the braced cluster hull or if it should be included. Any feedback on that?
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