Seems the retro fad continues - sail power

[Jethro_uk]

I have always wondered why wind power isn't used in moving sea cargo around since I was a lad ...

[Jim the Geordie]

One of those Tomorrow's World ideas we forgot about?

[The Natural Philosopher]

Because it is shit.

I can do better than that...

[Soup]

How so ?

[alan_m]

There was a very good reason why large sailing ships became mainly obsolete 150+ years ago. Even the hybrid vessels of that time (full sail plus steam engine) were soon abandoned as a design.

The vessel shown in the OPs link has a modern take on using sails but there are possibly some drawbacks such as extra drag and stability when the wind isn't blowing in the direction that the ship needs to go and during storm conditions. There are possible shortcomings with loading and unloading with the sails getting in the way of dockside cranes etc. No longer are cargos man-handled to and from cargo ships.

[alan_m]

In addition, if the ship is travelling at a speed greater than what the sails can provide then they become ineffective and and increase inefficiency. Journey time is money so slowing down a ship just to use the sails may cost millions for a large cargo ship. Putting sails on bulk carriers is just another impractical green idea.

[The Natural Philosopher]

The point is that in the end the cost benefit of using sails versus even shitty coal powered steam engines with a reliable top speed of little more than a slow trot, was massively in favour of tramp steamers, not clipper ships. One engineer, three stokers, a captain and maybe a first officer replaced a crew of tens needed to trim sails. And journey times were as good as or better than the clipper ships, because the tramps simply plodded on in pretty much any weather conditions whereas the clippers did not. And as pointed out, loading and unloading was way easier without all that top hamper in the way.

The same problems of intermittency, high maintenance and high cost plagued the sailing ships as much as they do modern wind turbines.

The obvious solution today is (armed) nuclear powered container ships. That can outrun pirates and destroy them as well...

Companies in the UK, Norway, Sweden and elsewhere are looking into nuclear reactors for container ships.

[brian]

In message <uta014$3k1q0$ [e-mail], Jethro_uk <jethro [e-mail] writes

Well shiver me timbers.

"which is amplified by smart vacuum technology" Wonder what that is. Mr Google is unhelpful here.

Maybe it's sucked along by a gigantic Dyson.

Brian

[The Natural Philosopher]

I think you are overly optimistic., It's just yet more carefully crafted bullshit, like 'sustainable development'

Which if you pause to actually think about it is, in a finite universe, totally impossible. Everything has limits.

The tragedy is that people simply do *not* stop to think about it, they swallow it and regurgitate it as a sign of moral virtue, all without the inefficiencies involved in passing through their brains..

[Colin Bignell]

At a guess, it could be something similar to trials done with a Miles Magister, many decades ago. The wings were covered with perforated sheets, which, using a separate engine, drew air through the tiny holes. This prevented the surface layer breaking away and creating turbulence, resulting true laminar airflow. However, for an aircraft, the benefit was not enough to justify the additional weight and complexity.

[alan_m]

Many of the UK main trade routes of the time were with the Empire and by

1870 the Suez canal was open. Even a shitty tramp steamer could use the canal while clipper ships couldn't under their own power.

[SteveW]

The reason sail disappeared was the unreliability of the wind (not a problem with an engine sized to be able to complete the entire journey without wind or with adverse winds, if necessary); the manpower needed to set, adjust and maintain the sails and rigging (not a problem with powered systems and no need for ropes); and obstruction for loading (again not a problem, with "rigid" systems that do not require miles of rigging that gets in the way).

All the sails have to do is reduce fuel use enough to be cost (including carbon taxes) beneficial.

It says that it can fold the sails - likely lying them down at deck level, so little drag or roll effect.

With no rigging, there will be little interference with loading. Indeed, many ships still have masts for mounting aerials, derricks for self-loading and unloading, etc.

[The Natural Philosopher]

There were more than UK trade routes and whilst what you say is true, I dont think it was a major factor.

I suspect the Suez canal was built because steamships could use it, (and the Mediterranean), whereas sail in the congested island filled Mediterranean was a tricky business.

In reality steam was already increasingly dominant by 1860, and the clipper ships already in decline.

The multiple expansion compound steam engine was by then the thing to have, and it was a lot better than what came before, in terms of reduced size and weight and coal requirements.

Steam was simply streets ahead.

The same transitions were taking place in the UK industry where reliable steam power was replacing all the wind and water mills.

e.g.

"The steam engine on the Old West River (Great Ouse) just south of Stretham was built by the Butterley Company of Derbyshire in 1831, at a cost of £4950. It replaced four nearby windmills and its scoop wheel was used successfully for over a century to lift water from flood channels back into the river. Powered by coal that was brought by barge, it consumed a ton of fuel every four hours. "

After WWI they switched to Diesel, and then to electric.

Simply because every change resulted in less manpower and more efficiency.

Today the East Anglian Fens are drained by unattended float level controlled electric pumps.

Not f****ng windmills. Those are just museums

The ONLY reason we are using windmills today is because of lobbying by german windmill companies and the mandatory imposition of a 'renewable obligation' which doesn't even mention carbon emissions. And does nothing to alter them

[Andrew]

Docking with engines is so much safer and easier

Sometimes.

[The Natural Philosopher]

Probably. Blown flaps and slats were (and still are) far easier ways to achieve more low speed lift.

An interesting experiment was done with formula one with fans sucking the car to the ground. It is still the way to achieve maximum acceleration and grip at slow speeds, but they banned it.

Anyway, as the saying guess. Nothing sucks like an Electrolux, except a Dyson

[The Natural Philosopher]

+1

Well therein lies the rub. In fact you can save the most fuel by slowing the ship down.

So the economics of transporting freight are a balance between less tonne miles per year against fixed financing costs of the ship, or higher fuel costs, and higher finance costs to build and maintain the extra complexity of the 'sails'.

I feel reasonably sure that if it were that much of a good idea people would have been doing it for years.

Just increased complexity, fragility, and capital cost.

Not most container ships. They are 100% dockside crane grabbers

>

[SteveW]

But, for modern ships, the sails are to *assist* the engines, reducing consumption. If the wind is wrong, they will simply be folded out of the way.

The problem with loading and unloading was not due to the masts (which these rigid sails resemble), but to the many miles of rigging, running all over the place. The modern systems not requiring rigging would be little affected.

Widescale nuclear propulsion would always run the risk of release due to collisions, attacks, etc. Many countries would likely ban nuclear powered vessels from their waters - some have already done so with friendly powers' warships.

[charles]

Yes, I remember this - around 1960- when I was at University.

The object was to provide short take off and landing. Concrete for longer runways was cheaper.

[The Natural Philosopher]

If they don't want global trade then they are free to do that.

Much of the confusion in these discussions arises from the fact that people consider that nuclear power is an alternative. It isn't.

It is the *only* alternative...

It will not be driven by choice or moral argument but by the simple fact that if you pull fossil out of the equation it is *all* you have left. (that actually works)

[Chris Hogg]

The 'Savannah' comes to mind