[mike_d]

Every "I'm going to start with a shipping container" solution eventually runs into the same problem: shipping containers are effectively empty soda cans. They are only strong when loaded exactly as expected.

Have you actually talked to anyone in the cargo ship industry about your idea?

[bkor]

> Have you actually talked to anyone in the cargo ship industry about your idea?

I worked in the container shipping industry. It doesn't sound like this person ever talked to anyone in the industry. It's not like "add a sail" hasn't been thought off loads of times before. I've seen a few times where people spend 6 months to run a project where they never talked to a person with experience. Then that project would eventually fail. Circumstances and restrictions sometimes change over time, so trying to solve the same thing every few years is a good thing. But "sail in a container", ehh..

[Turskarama]

Ultimately they don't need to use an actual standard shipping container but just a container that's the same shape on the outside.

[garrettgarcia]

It's not their container that's the issue. It's the containers below it.

[someweirdperson]

Is the sail-container sufficiently heavy to stay in place, or does it need pull on something that's holding it down?

If the sail is pulling, the container below would see a remaining uneven load from above. Is there a limit to this? Loading/unloading an unbalaned container sounds like a problem, but is it, while sitting on the ship?

[theflyingpigeon]

To me the problem is transmitting the force generated by the sails to the body of the vessel

A small to medium vessel fully loaded is like 150.000 tons. 10% of that is 15000 tons, imagine the force that needs to be transferred to the structure of the ship in a place where it was not designed to handle that force.

[someweirdperson]

Mass of the ship would matter if it was supposed to hover. Trying to google for engine thrust I found numbers that might be in the order of magnitude of 500kN (hp translated to pounds at certain speed). 10% of that through the kite 500kN. That would be enough to lift 50t, which is at the order of magnitude of the maximum mass of a shipping container. Looks like it might work.

[theflyingpigeon]

The mass is actually 50.000 tons, I typed wrong. My point is not the force to move the mass of the ship, but transmitting that force to the structure of the vessel in order to move it forward. It’s a lot of force, the structure is not made for that

[algorias]

"soda cans" is very pessimistic. The structural integrity of containers is very high. Specially the end walls.

The typical problem with containers is non-standard or unsecured cargo pressing against the side walls, which are indeed very weak.

[IshKebab]

Nonsense. Drinks cans are strong when filled because they are pressurised. Containers aren't pressurised. Their contents have no effect on their strength.

[mike_d]

That is why I explicitly said an empty soda can.