Build a 1 Million Tonne Cargo Net: Tech & Materials Needed

  • Thread starter chasrob
  • Start date
  • Tags
    Net
In summary, it is not possible to create a net that will support 1 million tonnes of one tonne iron chunks using today's technology.
  • #1
chasrob
185
58
I'm writing a sci-fi story. Is it possible, using today's tech and materials, to make a net that will support 1 million tonnes of one tonne iron chunks? It must be one-point lift and withstand a couple gees acceleration/de-acceleration.
Thanks for your help.
 
Physics news on Phys.org
  • #2
One million tons is about the weight of the Golden Gate Bridge at 1g. Twice that at 2g.

The largest crane can lift about 20000 tons.

A single point lift needs a shackle and a cable strong enough for the load, so it is more than the net.

I think the answer is no.
 
  • #3
anorlunda said:
One million tons is about the weight of the Golden Gate Bridge at 1g. Twice that at 2g.

The largest crane can lift about 20000 tons.

A single point lift needs a shackle and a cable strong enough for the load, so it is more than the net.

I think the answer is no.
The lift is made by superhero, who can easily bench gigatonnes :). So I suppose the net must be designed to be thin enough to be gathered together and slung over his shoulder, heh.
XPft7kZ.png

The iron chunks could be assumed to form a rough sphere 60-70 meters in diameter, if my calculator hasn't let me down.
 

Attachments

  • XPft7kZ.png
    XPft7kZ.png
    4.7 KB · Views: 453
Last edited:
  • #4
This calls for a calculation. McMaster-Carr lists ropes made of Spectra and Vectran. Both of these materials list a breaking strength of 20,000 lbs in a 1/2" diameter rope. Your superhero wants to pull 1,000,000 tons X 2 G's = 4,000,000,000 lbs force. Assume a safety factor of 2, then 4,000,000,000 / 10,000 = 400,000 ropes. Each rope has cross sectional area of 0.196 square inches, so the total cross sectional area is 78,500 square inches. If the superhero squeezes the bundle of ropes until each rope is in fully contact with the adjoining ropes, then the rope bundle will be 316 inches (26.4 feet, 8.0 meters) diameter. The superhero will need big hands, will need to squeeze hard enough to pull 4,000,000,000 lbs without slipping, and will need to pull in such a way that the force is distributed equally between each and every rope.
 
  • Like
Likes chasrob
  • #5
26 feet? Whoa, the superguy is human sized and not Mr. Elastic :). Know nothing about Spectra or Vectran, but I wonder if the ropes were arranged in a interconnected matrix, like nets, would it would increase lifting capacity over simply roping them together? (if I understand you correctly) When I was in the USN they had steel ropes. How about Kevlar or carbon fiber (if that's available these days)?
 
Last edited:
  • #6
I searched MacWhyte wire rope, and found a 1" diameter rope with rated breaking strength 151,000 lbs. You can do the math from there. Spoiler: The superhero still needs big hands.
 
  • Like
Likes chasrob
  • #7
He could stand spread eagle and press his cape against a block/wedge. So long as he is not sinking into the surface he should be able to spread the force out. That might give him 2 m2. A 2 meter concrete column can hold up about 40 to 80 million Newtons of force. So at 1g concrete is limited to less than 8,000 1 ton blocks. Porcelain has compressive strength closer to 500 MPa so maybe 100,000 tons.

chasrob said:
..The lift is made by superhero, who can easily bench gigatonnes :)...
Try picking up a block of margarine using a toothpick. The problem is a palm smooshing into the steel block. The hydraulic press channel has lots of demonstrations of what happens when you apply too much pressure. Here they do a ball bearing. Here is diamond.

chasrob said:
... So I suppose the net must be designed to be thin enough to be gathered together and slung over his shoulder, heh.
...image...
The iron chunks could be assumed to form a rough sphere 60-70 meters in diameter, if my calculator hasn't let me down.

If the net is long and stretchy he could accelerate the cables at several g. If the net has similar mass to the iron payload it could lift it a short distance before falling back down. That would not look very heroic.

Why not throw the iron blocks 1 at a time?
 
  • #8
stefan r said:
[...]
Why not throw the iron blocks 1 at a time?
There are many trillions of tons of blocks gathered together in low Earth orbit (long story) and he wants to transfer the lot Earth'side as fast as possible; a net seemed obvious, heroic or not. Therefore, million ton parcels. Matter of fact, larger than that would be even better but he has to employ current tech/materials.
 
  • #9
chasrob said:
There are many trillions of tons of blocks gathered together in low Earth orbit (long story) and he wants to transfer the lot Earth'side as fast as possible; a net seemed obvious, heroic or not. Therefore, million ton parcels. Matter of fact, larger than that would be even better but he has to employ current tech/materials.

If they are in low Earth orbit the net does not need to accelerate at 1g. He just needs to adjust the orbit so that it intersects the atmosphere.

If you have a trillion tons of iron in orbit you should build an orbital ring system. Here is a paper by Paul Birch published in the 1980s (part 1, part2, part3) and a youtube video by Isaac Arthur.
 
  • Like
Likes chasrob
  • #10
stefan r said:
If they are in low Earth orbit the net does not need to accelerate at 1g. He just needs to adjust the orbit so that it intersects the atmosphere.
Wouldn't that burn up valuable tons of iron? He planned on dropping the net and its load manually :) to a soft landing Earth'side, taking less than 5 minutes, and continuing until all the iron is landed. That's when the inertia safety factor comes in (the gees). He would like a billion ton capacity net even more, heh.
Orbital ring system... looks interesting.
 
Last edited:
  • #11
chasrob said:
Wouldn't that burn up valuable tons of iron?...

Is far more valuable in orbit. It costs $millions to launch a ton into orbit. If you have feedstock you just need a small processing plant. A few rollers would be enough to make a lot of structures. Electron beam welders and plasma cutters are much lighter than the rollers.
 

Related to Build a 1 Million Tonne Cargo Net: Tech & Materials Needed

1. What is the purpose of building a 1 million tonne cargo net?

The purpose of building a 1 million tonne cargo net is to have a large-scale, heavy-duty netting system that can be used to transport and secure large quantities of cargo, whether it be on land, sea, or air. This can be especially useful for industries such as shipping, construction, and logistics.

2. What materials are needed to build a 1 million tonne cargo net?

The materials needed to build a 1 million tonne cargo net will depend on the specific design and purpose of the net. However, some common materials that may be used include heavy-duty ropes, cables, chains, and metal rings. The net itself may be made of materials such as nylon, polypropylene, or polyester, which are strong and durable enough to support heavy loads.

3. What technology is involved in building a 1 million tonne cargo net?

Building a 1 million tonne cargo net will likely involve the use of advanced engineering and construction techniques. This may include computer-aided design (CAD) software to create precise and efficient net designs, as well as heavy machinery and equipment to handle and assemble the netting system. Additionally, the net may be equipped with sensors and monitoring technology to ensure the safety and security of the cargo being transported.

4. How long does it take to build a 1 million tonne cargo net?

The time it takes to build a 1 million tonne cargo net will vary depending on the complexity and size of the net, as well as the availability of resources and labor. However, it is likely to be a lengthy and complex process that may take several months or even years to complete.

5. What are the potential challenges in building a 1 million tonne cargo net?

Some potential challenges in building a 1 million tonne cargo net may include the high cost of materials and equipment, the need for specialized engineering and construction expertise, and potential safety hazards during the building process. Additionally, ensuring the strength and durability of such a large and heavy net may require extensive testing and modifications, which can also add to the overall time and cost of the project.

Similar threads

Replies
3
Views
1K
  • Sci-Fi Writing and World Building
3
Replies
96
Views
6K
  • Sci-Fi Writing and World Building
Replies
10
Views
4K
  • Sci-Fi Writing and World Building
Replies
5
Views
2K
  • Sci-Fi Writing and World Building
Replies
10
Views
2K
  • Classical Physics
Replies
30
Views
3K
  • Materials and Chemical Engineering
Replies
12
Views
2K
  • Science Fiction and Fantasy Media
Replies
13
Views
5K
  • Sci-Fi Writing and World Building
Replies
15
Views
3K
Back
Top