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Erik

What about wind powered or solar powered dredging boats?

Human Power Plant

That's not so practical, nor sustainable. Dredgers are mobile, so they would need batteries. And those batteries would need be to be huge. A 30,000 kW dredger would need a 30,000 kWh battery to operate for one hour.

That's roughly 600 Tesla Roadster batteries. These take a lot of space (not practical) and a lot of energy (every time the battery needs to be replaced).

Job van der Zwan

> The province of Friesland, in the north of the country, reveals yet another alternative to dredging. The Frisians never used dredge mills, horse mills or other tools than dredge bags. They continued to dredge by hand until the arrival of the steam engine.

While I empathise with the idea, I cannot see how that is going to work on the Rhine–Meuse–Scheldt delta, being the access point for some of the main rivers for cargo transport in Europe. Well, unless we convince *everyone* in Europe to switch to these types of cargo boats. And they probably have less capacity overall.

https://en.wikipedia.org/wiki/Rhine%E2%80%93Meuse%E2%80%93Scheldt_delta

I was told (but don't have a source for this) that transport in bulk goods over water is still the most sustainable (or do trains surpass that?) so this would be a difficult trade-off to make.

Mario Stoltz

One reason why today's containerized trade relies on heavy dredging is that even the largest ships need to go alongside the quay to be unloaded to land, then many of the containers are loaded again on smaller feeder ships. Only a smaller part of the cargo goes to trains or trucks.
Until the early 20th century, it was perfectly normal that most of the cargo from seagoing ships was not unloaded to land, but to barges (lighters). These were taken either to other ships or upstream on rivers in a tow.
In principle, this way of reloading cargo is possible with Containers as well. However, it will require large transshipment barges with container cranes and better planning (transshipment barges cannot store hundreds or thousands of Containers). It also requires a fairly large area of calm sea. Given These boundary conditions, you can do away with having to dredge seaports for the largest ships right up to the quay.

Human Power Plant

@ Job van der Zwam

Maybe we are shipping more than enough stuff around already? So less capacity overall wouldn't be such a problem.

Transport over water is indeed considered to be the most sustainable means of transportation. But we should also take into account the energy required to build and maintain the infrastructure, which scientists have only started to do recently. For example, the sustainability advantage of trains -- compared to planes -- turned out to be smaller when the rail infrastructure is taken into account:

http://environmentportal.in/files/Environmental%20assessment%20of%20passenger%20transportation.pdf

Furthemore, the fact that ships are more energy efficient than planes or lorries, doesn't make them "sustainable". The total energy use for shipping (and its infrastructure) is still problematic.

@ Mario Stolz

That's a very good point, thanks

Erik

Couldn't the dredging work be reduced by arranging so that incomming water is lead through a trap where silt and clay could accumulate and then be more easily removed and perhaps utilised. The trap could be either a basin with low speed flow causing particles to sediment or some kind of device e.g. a hydrocyklon where hydrodynamic effects are used for the same purpose.

LazyReader

It can be done electrically.
The ship can be powered, not by battery but by cable from the mainland. The cable is just like undersea cables to power island communities. The cable can float on floating blocks like swimming pool ropes. The power can run electric powered dredgers and a man can keep a watchful eye on the floating ropes.

darthgently

At the end of the article is the phrase "simple and ingenious tools". Simple and ingenious tools is just another way of saying "peasants providing semi-slave labor". There goes the hope for a 30 hour work week. Dear Leader commands the proletariat to perform manual dredging duty every weekend in perpetuity

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