When will leisure craft adopt the new sailing systems?

Fantastic to see someone is working on meaningful research. Good luck with that!

 

You will be surprised by the actual data. Rotors have less windage than the Bare Poles required for setting equivalent sails, so even IF you can furl wing sails, Rotors don't represent any windage problem.

Also, Wingsails have far more Heeling moment in operation, which can be a problem for Cargos that are restricted to less than 10 degrees of heel



https://www.naos-design.com/staging/wp-content/uploads/2019/08/FlettnerRotorvsWingsails.pdf

 

Yeah, right.
Somehow that pic doesn't seem to match the relatively small boats that the "yachtsmen" that you mention go sailing in.
Log entries such as the one you quoted are basically meaningless for probably 99.9999% of sailors.
These kinds of threads come up on a regular basis.
Starry eyed people who want to scale-down large industrial devices thinking they will revolutionize small boat sailing.

 

...and system difference.
The maintenance is different, the understanding is different, everything is different, unusual, out of the norm.
Not a known entity, never had to troubleshoot that before.
Plus, the marketing usually out shadows the reality, so lack of understanding again.
A.K.A. "Change" -few like it.

 

<sigh...> I don't even know where to start. I take it you actually haven't done a rigorous analysis of the data presented? Ok, let us start here...

Look at page 4; First statement..."The thrust forces generated by wind systems shall practically reduce the total ship resistance, therefore reducing the propeller power by the same amount divided by the propulsion efficiency." This is patently untrue. The total ship resistance is: 1) not reduced by the thrust power of the aerodynamics, rather the necessary Pe total is reduced by the effective Pe of the wing/rotor Thrust*Va; and 2) the Pe total is not constant based on the TWA as the TWS is only 8 knots but the Va is a fixed at either 18 or 20 knots. This means that there is always an apparent wind on the bow but the aerodynamic "lift" and "drag" changes between the rotor and wing sails due to projected area and apparent wind speed. Because of the variables used in the tables are not sufficiently defined (what is the difference between Pb and Pb net when calculated "Pe rotor" and "Pe wings" are correct), it will take me a day or two to pick out what math has been used based upon the geometry. It is immediately telling that the actual total ship resistance "Pe total" is never stated though it is easily calculated during trials and the energy to spin the rotor is given as "7% of Pe (total?)". Furthermore, page 5 is a total non-sequitur to the preceding 4 pages and seems to be inserted as an afterthought.

If this is a "report" I have questions for its author. Suffice to say, I have serious reservation about the linked document. However it is apparent that the topic of this "paper" is that wing sails are more effective (based on pages 3-5) because of the 7% reduction in "net" Pb and that thrust in the tables is always greater from the wing sails even though a significant unquantified amount of power is being used to drive the ship ahead into the wind.

 

I know I came off as quite harsh.
That said, there is a whole other aspect to "sailing for pleasure" that is seldom discussed or hard to quantify or measure but is very real indeed.
It's similar to what many airline/commercial/military pilots do when they have some free time after they've spent hour after hour in the cockpits of sophisticated/technologically advanced/high speed aircraft.
They put on their leather jacket and goggles, climb into an open cockpit biplane, or some such anachronism and zoom around in the sky for "Fun".
For a while they can "connect" if you will, with the Red Baron, or Lindbergh, or a WWII fighter pilot.
Sailing has a somewhat similar appeal.
You hoist up some fabric, pull some strings, feel the motion, you're moving.
You're doing the same thing in the same manner as people did thousands of years ago.
Suddenly going 6Kts feels like you're flying. It may only be for a few hours or a short vacation, but in your mind you could be heading for Tahiti, or simply trying to beat the boat near you back to the club dock.
Geared contraptions and rotors and cylinders and wings are not part of the "essence" of what sailing is all about.
All that kind of stuff is food for academic digestion and fiddling with engineering, it has no "Fun" in it.

 

I think the main difference between commercial "big" ships and "small" leisure craft is that cargo ships are trying to reduce fuel consumption. The main reasons might be reducing fuel costs as also reducing emissions (might get important in the future). Powering a leisure sailcraft with normal sails is just a good, proven and well known manner and basically no changes are needed. Whereas a cargo freighter has some restrictions regarding wind powering, a flettnerrotor or a kite fit much better on a cargo ship than normal sails. In cargo shipping it's mostly trying to reduce fuel consumption by wind assistance whereas sailboats are powered mainly by wind instead of assisted. There's no really need for changes in sailboats though it would be interesting and maybe the future will show there is a better way for sailboats to be powered.

 

New ways to enhance Magnus effect...

 

My father sailed all his life. His business was headboat owner/captain, but his pleasure was sailing. He bought, sailed, and sold a dozen sailboats on his journey to finally circumnavigating the globe. He and I used to discuss the relative benefits of various design aspects to these and other potential boats for sailing. Always, my father referred back to efficiency. He did not want to take seven days to sail somewhere if an availible solution would get him there in six and a half days. Yet, he chose to sail there.

I, on the other hand, wanted sail in a style that was more reflective of my personality. I wanted to try out the concept of the flatbottom, planing hull (too much skin friction, too wide and rolly). I like the nautical tradition (not efficient), various futuristic rig ideas (won't work at sea, untried, poor concept, or "that's an interesting idea").

My father owned a custom 3 masted schooner designed to carry a family of five around the world.
Clark Mills designed it shallow and skinny with sails that could be handled by one sailor. Simplicity was the main goal (1970s). My father sold it, moved his family to the mountains and proceeded to pursue his goal with a, freedom 44, a Shannon 50, an Amel 50, various J boats. He finally got the chance to finish his round the world trip on a J 44.

Anyhow, all this time, I had various conversations with him and a few of his friends who sailed. I would say that the main change for cruising and semi-serious sailors is the racing world. When an AC boat wins with a Flettner rig, they will be popping them onto cruising cats in no time.

-Will

 

Nice story. Formula1 cars win races, but you wouldn't want to drive one on the road.

 

Don't you know people who live for speed?

In practice I don't think any Formula 1 cars are street legal, at least not in the U.S. But I could be wrong. There are cars that kind of look like them.

I've known many whitewater boaters who love to push the limits of their athletic skill and ability, and some sailors do the same. A self-driving boat wouldn't give most of them the same joy.

Virtually all outdoor sports are somewhat open ended, and it is a good idea to master some of the skills of handling unanticipated conditions. Even for those of us who try to avoid the most difficult conditions, learning to handle what we can is part of the fun. People who hate that eventually tend to drop out, one way or another.

Perhaps there is more of a market for an alternate sailing system if it isn't "push-button simple".

That doesn't mean you wouldn't enjoy such a boat. I'm certain you could find someone here willing to build you one, for a nominal fee. Maybe some of the same people who poo-poo your idea.

If you have those skills yourself, maybe you could build and market such boats. A lot of boaters try to avoid challenging conditions. You can walk into most large department stores and find boats meant for them. It must be a bigger market than boats designed for people who seek out difficult conditions.

 

Not really. It is an inefficient and troublesome way to travel. However, many of us love the ridiculous and unnecessary work.

 

But your car benefits from their tech.

 

Racing absolutely subsidizes trickle down r&d. Bikes, cars, boats, all benefit from folks throwing tons of money at competition trying to find that edge. Then someone else comes along and streamlines the process and it's widely adopted by the masses.

 

You have got to bear in mind that large organisations are spending millions on developing these new systems, companies like Norsepower, Bound4blue, Econowind, and many others. They would not be doing this if they did not believe that these systems were better than rope and canvas.