Thanks as always for the great info Pierre.
Sometimes my brain is a little slow. Upon further reflection I realized I had seen this “Michelin-Man” sail shape before, and that we were talking about this years ago.
But from these Michelin promotional videos showing ships, we can see that they are all just renderings.
So my question is, if these sails have been around for, what, maybe a decade, why aren’t they actually being used?
If you right click on the above videos provided by Pierre, you have the option to open a video in a new tab and you can see the dates, comments, etc.
One comment reflected my thought, which is about how extra-strong a telescoping, cantilevered internal mast, with no guy wires to stabilize it, would have to be, compared to a normal mast with guy wires. There must be a reason why, after all these years, we don’t see ships using them. It’s not as though Michelin doesn’t have the money or reputation to move such a concept forward. So as with all such “press-release breakthroughs”, I wonder why there don’t seem to be any in actual operation.
There are things that kites can do superbly- recreational kite sailing, kite boarding, buggying, sports kite flying, snow kiting, possibly kite energy systems and so on- more than enough for a kite industry many times its current size, but powering commercial shipping is not one of them.
Peter Lynn, Ashburton NZ, February '09
PS, I’m an optimist
This diagnosis remains relevant more than 15 years later.
The question remains as to “possibly kite energy systems”:
there were a few prototypes, a lot of scientific studies, and embryonic commercialization. Given the considerable resources but also the complexity of the means to exploit them, the question remains open. And in the event that real successes are recorded, this would call into question the non-suitability of powering commercial shipping at industrial scale, and vice versa.
The kite operates at ~300m and harvests so-called high-altitude winds. High-altitude winds are much stronger and more constant than winds near the ground and have a 95% probability of occurrence offshore globally. Additionally, we analyze weather data systematically and use our own route planning tool to calculate the optimal route for our ships and thereby avoid areas with no wind. As a backup, there is still a diesel-electric motor.
Wind gradient is lesser far offshore. So the advantage of high-altitude winds is also lesser.
By planning for smaller ships, it is implied that the large units pose a problem, which Peter Lynn had already anticipated.
Could the implementation of smaller units solve these problems?
As well as unacceptable reliability because of wind variability, there is a technical reason why kite power cannot be useful for commercial shipping- unless container ships change to submarine form so as to reduce their above-water-line drag profile. Aerodynamic drag is the killer. A largish container ship, with containers stacked up 15m and more above deck level can have side area above the water line of about 5000sq.m. Even if it’s kite is also 5000sq.m’s (5 x larger than any kite that’s yet been built, but probably possible), the ship’s superstructure drag will reduce the efficiency of the kite/line/ship system (measured by lift to drag ratio, L/D) to less than one, and options for upwind courses will fade away.
Ships would be smaller, in first in volume, and in second in area. So the drag issue would remain, although in a lesser level. And “unacceptable reliability because of wind variability” remains a major issue. And close-hauled can be difficult. It can be expected that the backup would often be requested.
This is an idea I’ve also had for some time, however, just because I have an idea, doesn’t make it a good one. Usually there are several “holes” in the concept. Maybe a few work out, or even have a chance.
One immediate concern for shipping is security. The people promoting this idea are probably honest, surrounded by other honest people. The population is skilled and more interested in producing useful things than stealing useful things.
Let’s say you are shipping BMW cars in containers around certain continents known for dangerous shipping due to piracy. What do you think would happen to a little kite-powered boat with a container holding a couple of new BMW’s?
Already, many stolen cars in Canada, as one example, are driven directly to shipping containers, which are then illegally loaded onto ships, sold at high prices at their destination country, only to end up as registered vehicles in Nigeria.
Meanwhile, this group’s website acts as though they already have a working business, explaining how they work with shipyards to build their ships, except they don’t actually have any ships.
Most of the buzzwords are very familiar to us by now. I’m thinking it’s one more of the hundreds of “press-release breakthroughs” we’ve become accustomed to, which, if you’ve paid attention, never seem to actually go anywhere. Sounds nice though. But don’t they all? Can you say “vaporware”?
