When will leisure craft adopt the new sailing systems?

Just came across this "alternate" rig that crossed the Atlantic

 

I watched the video a while ago and had to find it in my history, but I thought it was built to be functional (maybe I’m mistaken) and figured it was worth posting since this thread was about leisure craft and adapting/adopting alternative propulsion.

Most people don’t have the budget to go out and build from scratch and would probably take a similar approach modifying an already built vessel using readily available materials and their basic skills set to accomplish their goal. I’ve seen a few videos of people doing this from small to large personal leisure crafts.

Movie prop or not, I thought the basic construction was applicable and an example of how much more complicated the system is in construction compared to more traditional methods of propulsion.

From memory, that’s what I had taken away from it.

I guess I’ll have to watch it again as I thought he had made a model and studied the tech and actually tried to apply it.

 

I was actually in communication with the designer some years ago. It DID work, ie Propel the Boat, but it was never trialled properly, or even optimised. He was quite disappointed that it never went past this stage.
The controls were quite primitive, and very basic.

The project was part of this program.


https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.2008.0136

Interestingly, the more futuristic "multilayer" concept was proven to be less efficient than the mock up.

"how much more complicated the system is in construction compared to more traditional methods of propulsion"
It depends on what you mean by "complicated"
To build a fully engineered, long lifespan rig, its only money to a set of engineers.
To operate, its totally turnkey
Here is the "control screen" for a full blown commercial vessel.
Everything Old is new again - Flettner Rotor Ship is launched https://www.boatdesign.net/threads/everything-old-is-new-again-flettner-rotor-ship-is-launched.24081/page-40#post-943731

 

So my post was relevant and the boat was more than just the crude “prop” you dismissed it as?

Interesting that you used it as an example a number of times in the Everything Old is New Again thread, yet reacted to my post the way you did, then followed it up with the info you posted.

I didn’t post it as an example of proof of concept, nor did I make any performance or operational claims.

I simply posted it because I thought it was relevant to the discussion of “leisure Craft” and an interesting example of a DIY adaptation of the technology as discussed and explained by a knowledgeable boat designer/builder, and that my take away after watching the video was that the overall design, construction, and installation of the rotors seemed more complicated than the mast(s) and sails(s) they replaced.

 

It's an interesting example of the real world bringing up issues that most of us don't think of. I didn't realise that the lower edges of the rotors would be moving at 100mph. Even if they just brush your skin that's going to cause a hell of a wound. so you really need a fully-fenced exclusion zone around each rotor, and that will take up a significant amount of deck space. The other thing that has me wondering is what happens when even something like crusted-on seagull poop comes unstuck at 100mpg and starts sending shrapnel around the deck. Eeeekkk!!!!

 

A fully battened, low-draft sail with a very bendy mast, squaretop roach and extreme twist along the lines of a twisty windsurfer sail could be used to sail a boat as in the video with little or no sheet adjustment. The extreme twist would mean that even without sheet adjustment, some part of the sail would be producing lift at different apparent wind angles. The full battens and flat chord would allow any area that was under-sheeted to operate at a very low angle of attack without flogging and therefore causing drag. A small sail with extreme twist and mast bend can depower itself very effectively in gusts.

Yes, a bermudan sail has to be raised, but that's not difficult and you get the very significant benefit that you don't have a wingmast spinning around, either well above the hull where it will cause more heeling moment than a conventional rig, or at hull level where it will take up a large amount of deck space.

I don't believe the claims that a full size wing rig will effortlessly feather because I know very sharp marine industry people who have found that their wingmasts did not feather effortlessly. To get a wing to feather requires some force to be created. The wing will not feather until the wind reaches the tail; until then the main wing is at an angle and must generate forces. Even if this is only for a brief time, it seems that these forces are likely to be significant in terms of causing a boat to feel heeling moment and movement on its mooring. We feel this effect routinely on small freestanding rigs, which I've spent countless hours using.

A high performance windsurfer rig has a non-fabric surface, double luff, rigid tapered carbon battens affixed to the carbon mast that lock the draft in, and a highly developed outline. It is effectively a rigid wing with a chord that can be inverted to allow it to go from tack to tack.

The interesting thing is that such wing-like sails lack the sort of efficiencies that many people claim wing sails have. For example, square running in light winds at fast displacement speed (the speeds most craft tend to sail at) these wing-like rigs don't sail at their best with attached flow in "wing like manner". They perform best with normal stalled flow as with a conventional rig. These wing-like sails are not a different beast to normal sails; each has their particular advantages and disadvantages.

The fact that wingsails are clearly no faster than good conventional sails has, as mentioned, been shown in Moths, A Class cats, 18 Square cats and other classes. Wingsails clearly work in certain craft like AC boats, but not in many others (even C Class cat sailors have said that their wingmasts are slower in many conditions than the cheaper conventional rigs of other modern cats).

If you have done so little sailing with modern conventional rigs that you think they work like a flax and wood gaff cutter of 200 years ago, you probably don't realise how well they work. As someone with four wingmasts and all the winglike non-cloth sails to go with them, I have zero doubt that the step between a modern "mainstream" rig and a winglike rig is far less than the yawning gap between a modern carbon spar/film sail rig and a "classic" rig like my wooden-sparred lugger.

A boat that goes in reverse as quickly as it goes forward must have an extraordinary hull shape. Even windsurfers, where the sail is of course totally independent of the hull direction, are slower in reverse because the rocker, entry, exit, foil shapes etc are all optimised for going forward. And yes, proas would normally be said to have extraordinary hull shapes.

 

Sigh. Nothing like getting things in context on the internet.

YES - it WAS just a Movie Prop
YES - It actually worked for the 3 days it was used, as it was designed to do, even "sailing faster than the prevailing wind"

You must have missed my comment " it was never trialled properly, or even optimised. He was quite disappointed that it never went past this stage.
The controls were quite primitive, and very basic."

There are plenty of movie prop cars that work for their intended role, but aren't worth keeping afterwards.

Didn't you ? The inference I got was that it was a totally unwanted version of working Flettner Rotor, because it didn't work/perform. The fact it was a "skip bin" project didn't get a mention.

 

The End Plates don't have to rotate as well. They certainly don't have to be sharp, if they do. We manage to survive fast spinning vehicle tyres quite well, with a bit of common sense.
Lets talk about gybing booms, and losing fingers in pulleys and blocks while we are at it.

 

To return to the subject of alternative rigs and whether they are effective.
It's clear that CTR249 is not a fan of wingsails. Perhaps he has not heard of Saildrone. Saildrone is a unmanned sailcraft for data collection which is driven by a wingsail and adjustable tail combination

Saildrones have sailed all over the world. Including California to Hawai and a circumnavigation of Antarctica without human intervention. Obviously this points out that they can survive extreme conditions quite well. Having built many small versions, the company are now bringing into service a much bigger 72 ft version. There is no doubt that the rig that they use would be very suitable for a manned version. The sailor would have very little to do as the system is mostly automatic. This could be the future for people who want to cover the world without all the hassle of sails and ropes and still use no fuel. Also there would be no deckwork, and although it is pleasant to go on deck on a nice day, if the boat can be worked without emerging from below in storm conditions it would be a great benefit. Such a system has been advocated by both Hasler and Roger Taylor who used Junk rigs, but the wingsail would be a better solution.
This is a version of the Saildrone called "Stubby" which is built to survive storm conditions - the wing is still controlled from the flap on the top rear and it is able to make progress into the wind at a 45 degree angle.

 

A bottle will survive the worst hurricane at sea. However, a scaled up bottle would kill a person inside in the same conditions. If you want to have unmanned craft, then it should not be in this thread which is about recreational craft with people inside.

 

It's my thread - it's not up to you to tell me what to say. I will say anything that is relevant. I'm not sure who you think you are. Some sort of moderator?

 

I really can't see any reason why a leisure sailor would adopt an unconventional rig.If he already has a boat with a functioning rig it wouldn't take anything like the cost to modify an ordinary bermuda rig for easier use by adding a winch or two and leading all lines into the cockpit.In addition,he wouldn't have reduced the market for the boat when he wants to move on.The junk rig enthusiasts have been pushing their advantages for years and they have succeeded to the point where I can count those I have seen in the last forty years on the thumbs of one hand.

 

Some like to do things differently, what a boring world it would be if we all did exactly the same things and followed on like sheep. So everything has to be conventional and nothing must change?

 

Change for the better is a welcome thing.Change for the sake of change is pretty pointless.If you can demonstrate that your better mousetrap really works then you may expect a stampede of eager customers to your door.If,on the other hand, we are dealing with a single issue fanatic who can't accept that his vision isn't widely shared then this thread is rather pointless.I and others have asked for specifics and been given little more than the locations of websites for those dabbling with fanciful systems that have zero to minimal market penetration in spite of decades of trumpeting the merits of non-mainstream solutions.I see no useful purpose in continuing this thread.

 

Your departure will be welcome. Here is a picture of a "fanciful system" being constructed by the multi-million dollar RoRo company Wallenius Wilhelmsen who employ 9,400 people and have a turnover of 3.9 billion dollars. I guess they would not agree with you. I suspect they are not "single issue fanatics"