I wouldn't write it off.

There could be could add battery storage to be used during the journey. They could include wind turbines to add further power generation.

Also ships can go slower. In my limited knowledge of boats every extra knot takes significantly extra fuel. If we were bringing multiple power sources 'slow' cargo may be viable. And the has to be other ways to increase this function.

And there is always hybrid. Not all power has to be renewable sources. A solution could start with supplementing diesel driven thrust with some lower cost green power. Given diesel is 70% of shipping operating cost that seems a potential option.

I think the number one obstacle to this is it would be nowhere near viable from the costs perspective.

No one really wants to build cargo ships right now, shipping companies are barely staying afloat right now because there is a glut of cargo capacity.

This technology would need to be cheap enough that it would make sense to retrofit a ship with it... which would probably not be the case for a very long time.

I do think it's a very thought provoking idea however.

I was under the impression that cargo capacity is currently expanding. Maersk is taking delivery of 11 new ships within the next year and a half: http://theloadstar.co.uk/maersk-refines-fleet-second-generat...

I'm under the impression that both are true. There is overcapacity in the shipping market, which drives down prices. Because prices are low, shippers are investing in ever larger (more efficient) vessels, in order to turn a profit. This in turn leads to more overcapacity, which leads to a drive for even larger and more efficient ships.

It's a type of 'tragedy of commons' situation, where every shipping company is making the right decisions from their individual perspective, but collectively they're driving themselves into the ground.

For me this explains the rise of slow-steaming. It makes a lot of sense in this market because it lowers the cost of shipping a container (less fuel), while simultaneously reducing the market capacity (# of containers / year).

Finally, very few shipping companies make money on the major lines (e.g. China to Europe), because it's pure price competition. They're much more likely to make money in places where they have a 'monopoly' on something: e.g. being the only ship that leaves in the next 3 days, or being the only shipper going to a specific location. For example inter-Africa shipping falls in this category.

An additional detail is also the expansion of the panama canal which allowed more and larger ships to travel through it cutting down the travel time for larger cargo ships eliminating a primary advantage of smaller vessels.

However ironically though, these mega vessels are considered with quite a bit of disdain by many in the industry. This link can provide quite the rabbit hole of information. http://www.supplychain247.com/article/state_of_ocean_contain...

> I was under the impression that cargo capacity is currently expanding

Further exacerbating the problem with the glut of cargo capacity.

Those ships were ordered a long time ago.

Norsepower provides modern sails: "a spinning cylinder that uses the Magnus effect to harness wind power to propel a ship."

"When the wind conditions are favourable, Norsepower Rotor Sails allow the main engines to be throttled back, saving fuel and reducing emissions while providing the power needed to maintain speed and voyage time. Rotor sails can be used with new vessels or they can be retrofitted to existing ships."

http://www.norsepower.com/

I love that you posted an 'in the wild' solution. So many people saying this is not possible. And then someone has found a creative way to offer one alternate. Such a good example of dont listen to the nay-sayers if you want to mentally explore something. There are almost always solutions and I'm sure there are more for this one.

No one said it wasn't possible. Clearly, it's possible since ships were wind powered for millenia. The problem is that with very low fuel costs, it's not feasible because the drawbacks outweigh the benefits.

Sure sails will be used for some limited applications. But Magnus effect cylinders won't be practical for the majority of cargo ships because they consume valuable deck space and interfere with loading operations. They would only make sense if hydrocarbon fuel becomes much more expensive.

Unfortunately the energy density of batteries is really bad (in the bigger picture) and, besides, we're supposed to be using weight for cargo. Tankers also burn very nasty fuels that can't be used for anything else - so in practice they're very efficient.

There have been cracks at putting "sails" of one form or another on ships but they've always been heavy, relatively ineffective and basically just not worth the hassle.

The speed of a ship is actually quite easy to work out. You find the time/value curve for the cargo and the cost/time for the ship and see where they cross - essentially. The long and short of it is that the lighter and more valuable your cargo is, the faster the ship goes. This is why container ships are much faster than oil tankers.

I've heard that cargo ships are currently prevented from going much slower because of the human crew. Drone ships could help.

The human crew isn't much of a factor in cargo ship speed. Ship owners would be happy to leave their crews out at sea a week longer if it was profitable.

Drone ships won't be practical any time soon because of maintenance problems. Crews spend much of their time at sea performing preventative maintenance, painting, and fixing broken equipment. With a drone ship all of that work would have to be done at the pier which would be far more expensive than paying a crew.

Then why don't they go slower? I would expect many cargoes aren't incredibly time sensitive.

They are already slow steaming on many routes. Ship owners aren't idiots; they have software to perform constrained optimization calculations to figure out the steaming speed which will maximize profit on each leg. This is based on fuel price, crew wages, asset depreciation, delivery contracts, etc.

I wonder if they could use an underwater wing design, similar to this (https://www.youtube.com/watch?v=u5SHn0SdXjw). You keep swapping the angle of the wing so it's always pushing forward whether the vessel is moving up or down, but it would be powered by the waves moving the ship. It might be possible to get a slow base load speed for 'free' with a large enough wings

Container ships are already going slower:

https://www.theguardian.com/environment/2010/jul/25/slow-shi...

I suspect nuclear (be it fission or - someday - fusion) would be much more viable for powering something at that scale in a "post-petroleum" scenario. There already are a couple fission-powered cargo ships out there, IIRC.

The problem is that safe disposal of nuclear fuel is nontrivial.

There are bigger problems with nuclear powered cargo ships than just waste disposal. They would need larger crews of highly trained (more expensive) experts to operate the reactor. Look at how much the US Navy spends to train competent technicians and engineers.

Every nuclear powered ship becomes a prime terrorist target, either to hijack it or destroy it in place and cause a radiological incident. So you also need constant armed security (also expensive).

A more practical way to have "nuclear powered" ships would be to use electric power from land based nuclear plants to manufacture synthetic hydrocarbon liquid fuels, then load that fuel on the ships. Nuclear plants on land are far more cost effective since they can be built much larger to achieve economies of scale on operations and security.

On the subject of highly trained nuclear operators from the Navy, what's the job market look like for those guys after they leave the service? Where else are you going to find a nuclear-powered ship where you can put your experience to work?

Seems like a natural fit. For almost everything in the military, IMO there should be some market in the private space that could use those skills.

Some of them stay 30 years in the service and then retire. Others go to work for civilian nuclear power plants, or the vendors which service and supply them. And there aren't very many trained operators to begin with. The US Navy has <90 nuclear powered vessels (plus a few separate reactors for training and research).

I'd like to add that cargo ships, while being very efficient in terms of how much they can transport over a unit distance given unit energy, require enormous amounts of energy.

See some resources:

- https://en.wikipedia.org/wiki/Energy_efficiency_in_transport...

- https://people.hofstra.edu/geotrans/eng/ch8en/conc8en/fuel_c...

Why not have solar modules in a shipping container form factor. (Maybe shorter in height though) and stack those at the top layer when loading the ship.

You could probably even find some ingenious way to run the current through the containers stacked umderneath to route the power. They are made of metal.

Shipping companies don't own the containers. Solar panels would get broken when they were transferred to shore. Panels and cabling would add more weight to the highest level of the cargo stacks: the worst place for ship stability. And even if you covered the entire top level with solar panels it still wouldn't provide enough propulsion power to be worth the expense.