RotorSwing stabilizer system

[123]

I posted the introduction of the "Jetten 50 MPC". As a standard option Jetten Yachts can equip the yacht with the RotorSwing Stabilizer. For who never heard of this system here some info.

RotorSwing "The World's First Retractable Magnus Effect Stabilizer"

RotorSwing is the first fully electrically driven, non-hydraulic roll damping system for yachts up to 30 metres based on the Magnus effect. Instead of traditional fins, the system uses rapidly rotating cylinders which, subject to the direction of rotation, generate an up or downward pressure.

The biggest advantage of RotorSwing in comparison to a fin driven conventional system, is the greater roll damping at lower speeds. To achieve effective roll damping with fins it is necessary to reach a substantial speed through the water. This is partly due to the fact that often, the surface of the fins have been designed to be as small as possible to reduce the risk of damage. In shallow water, protruding fins are, in particular, very vulnerable.

RotorSwing features retractable rotors, eliminating the risk of damage. The retracted rotors remain largely within the turbulent boundary layer1 of the vessel so that any resistance is negligible.

If the rotors are in use in the “Drive” position, they can protrude outside the hull of the ship. However, should the engine be put in to neutral, the rotors automatically retract. This prevents damage during maneuvering and berthing at quays, in locks and ports.

The rotors do not have any effect on the steering and therefore, unlike fin based systems, can be mounted at a position of choice. For the majority of yachts, this is likely to be dictated by the onboard available space for the compact electric motor. It is even possible to mount the rotor at the stern which, in particular for fast-moving yachts, may be preferable.

RotorSwing is the first fully electrically driven, non-hydraulic stabilizing system based on the Magnus effect. No expensive, vulnerable hydraulic pumps, cylinders or high pressure lines and no risk of oil leaks on board. RotorSwing is a product from RotorSwing Marine, founded by Theo Koop. Theo, the founder and owner of the former KoopNautic Holland, is, for good reason, known as “the Godfather of stabilizers”.

Link: RotorSwing

[youtube]0dxNaS8p1rI[/youtube]​

 

[healhustler]

Very interesting. Thanks for posting this. Just a month ago, I saw something like this sticking out of the hull of a big Krogen while it was being slung. I couldn't get close enough to see if this was the device or not.

 

[windmist]

This would sure be better than fins if it worked as well but it is a power hungry device. The specs say each rotor requires 1500W of 230 VAC power and averages 1000W of power. I assume you need 2 rotors so that would mean running a fairly good size generator when you need the stabilization.

I would sure like to see some independent reviews but can't find any.

Ron

 

[123]

This would sure be better than fins if it worked as well but it is a power hungry device. The specs say each rotor requires 1500W of 230 VAC power and averages 1000W of power. I assume you need 2 rotors so that would mean running a fairly good size generator when you need the stabilization.

I would sure like to see some independent reviews but can't find any.

Ron

I would suggest to power them with Hydraulic Motors with the Hydraulic Pump mounted on the main engine.

 

[RickB]

You mean these things?



http://www.trawlerforum.com/forums/s3/fathom-yachts-vs-nordhavn-11895-4.html

 

[MurrayM]

This would sure be better than fins if it worked as well but it is a power hungry device. The specs say each rotor requires 1500W of 230 VAC power and averages 1000W of power....

Please excuse my slope-foreheaded, uni-browed, knuckle dragging incompetance in all things electrical, but isn't that pretty much equivilant to turning on ten 100 watt lightbulbs per rotor? An alternator wouldn't even break a sweat, would it?

 

[RickB]

... isn't that pretty much equivilant to turning on ten 100 watt lightbulbs per rotor?

Or, since everyone loves talking about horsepower, they average around 1.35 hp to run but evidently can consume up to a whopping 2 hp!

For the torque aficionados among us, that is a gut wrenching, steel bar twisting, rotate your world, about 7ft lbs or for our metric friends, about 9.5 Newton meters.

 

[O C Diver]

Please excuse my slope-foreheaded, uni-browed, knuckle dragging incompetance in all things electrical, but isn't that pretty much equivilant to turning on ten 100 watt lightbulbs per rotor? An alternator wouldn't even break a sweat, would it?

Based on wattage, it would take the entire capacity of a 240 amp alternator to drive both of them at peak power consumption. This may not take into account peak draw in motor start up.

Ted

 

[MurrayM]

Based on wattage, it would take the entire capacity of a 240 amp alternator to drive both of them at peak power consumption. This may not take into account peak draw in motor start up.

Ted

Ahh, there we go, something I can (sort of) wrap my head around. Thanks Ted,

Murray

 

[RickB]

Based on wattage, it would take the entire capacity of a 240 amp alternator to drive both of them at peak power consumption. This may not take into account peak draw in motor start up.

Ted

Even if you ran them with a 12V motor (a really silly idea) they would still only consume about 80 amps each.

When operated at the 230VAC designed for they consume about 4 amps.

 

[O C Diver]

Even if you ran them with a 12V motor (a really silly idea) they would still only consume about 80 amps each.

When operated at the 230VAC designed for they consume about 4 amps.

As they are 230VAC each and you would have to run the 12 volt DC output of the alternator through an inverter to convert it into 230VAC. After you factor in line loss and inverter conversion loss, 2 of these units that run at a maximum of 1500 watts each will likely consume all of the output of a 240 amp alternator.

1500watts per unit maximum multiplied by 2 units divided by 12 volts equals 250 amps.

Ted

 

[N4712]

OR you can go with active fin stabilizers

 

[AusCan]

They sound interesting. But for once, i would like to see a promo video of a stabilizing system operating out on rough water; Maybe with a 4 ft beam sea, rather than a 1 foot wake in flat water.

 

[MurrayM]

They sound interesting. But for once, i would like to see a promo video of a stabilizing system operating out on rough water; Maybe with a 4 ft beam sea, rather than a 1 foot wake in flat water.

Bingo!

You'd think, after all that sweat equity and personal commitment to bring this to market, that they would want to show it off in all manner of gnarly following and beam sea conditions. Then again, maybe they don't

 

[Insequent]

OR you can go with active fin stabilizers

I gave my Naiad active fins quite a workout yesterday. My boat was put back in the water at Bulimba after Norman R Wright's had repaired the damage from the Canadian stevedores mismanagement of the slings. Wrights did a magnificent job of the repair.

So I had little choice to head back up to my berth at Newport Marina with a strong wind warning in effect, and seas 1 to 1.5m. Wind was up to 30kn, but mostly in mid 20's. The Naiad's kept the boat perfectly level port to starboard, and I was quartering the seas for most of the way. I was amazed that there was virtually no roll. And delighted. The fins were getting to maximum quite often, and moving/adjusting all the time. The control box has accelerometers in it and they sense movement very early and hence the flat ride.

Fore and aft pitching was a different story! Every now and then there was a significant rise and plunge. I decided it was best to keep up a bit of speed, and did most of the 25 nm trip at just under 10 knots. Sure, I got a fair bit of spray on the flybridge but it was still a pretty good ride. Little slamming, and momentum helped the ride I'm sure.

Contrary to an erroneous claim above, a good active fin installation will be designed to be effective at low speeds. I have 7.5 sq ft fin area. I get good response in the 5-6 kn range. Its true that at greater speeds they give more countering force, and I think I probably benefited from that yesterday. And good design/installation means that they don't protrude outside the hull sides, or anywhere near the depth of the keel. You would have to work hard to scrape them on anything. Although debris in the water can bump them.

I'd like to see some good tests of the cylinders the OP talks about. I would be curious about the snap-back effect. A friend had a powered gyro on his boat and the snap-back to correct a roll was sufficiently quick to ensure his wife got seasick. It was not a gentle roll correction at all. But that might also be because it was 'generic' gyro, and not the highly regarded SeaKeeper system. What would be really good is to have some hard data on all of these systems roll, measuring their damping/correction over time, to quantify the modified roll period.

 

[HopCar]

I've often wondered if trim tabs could be equipped with fast acting cylinders and a motion sensing control to act as roll stabilizers. Bennett has a sensor that will level a boat but I don't think the tabs react fast enough for true roll control.

 

[123]

.............................I'd like to see some good tests of the cylinders the OP talks about. I would be curious about the snap-back effect. A friend had a powered gyro on his boat and the snap-back to correct a roll was sufficiently quick to ensure his wife got seasick. It was not a gentle roll correction at all. But that might also be because it was 'generic' gyro, and not the highly regarded SeaKeeper system. What would be really good is to have some hard data on all of these systems roll, measuring their damping/correction over time, to quantify the modified roll period.

RotorSwing’s History and Design Background

The intent of Theo Koop was to create something unique. Theo wanted to make the world’s first electric Magnus effect stabilizer that was not only electrically powered, but also retractable. Theo had a big challenge ahead of him, to make stabilizer fins that protrude from the boat, are relatively easy to install, and are also kept safe from vulnerabilities in shallow water. The new RotorSwing system was the optimum solution; quiet, safe, and extremely effective, even at speeds around 4 knots.

By 1982, Theo had already designed the first line of retractable Magnus effect stabilizers with his company, KoopNautic Holland. Although his first prototypes were very effective at the time, the sealing technology against the seawater was still a challenge. A few of the initial installations that were delivered are still in operation, however, the maintenance on the rotary seals of these systems requires regular attention from the owners. KoopNautic Holland had to stop the production of the initial stabilizers due to the aforementioned sealing issues.

Since Theo’s first installations, sealing technologies have improved drastically. Having sold his stabilizer company and retiring, Theo got the urge to start again with a new stabilizer that utilizes the Magnus effect.

Theo and his business partner, Lambert Dinnissen of Quantum Controls, have proven experience and tenure in the design, development, and construction of large roll damping systems. They designed and engineered a complete line of fin stabilizers for both underway and ZeroSpeed® applications that are available for large yachts, commercial, and military vessels.

When Theo was first approached about designing and manufacturing retractable stabilizers for smaller power boats up to 20-25 meters in length, he immediately thought of the Magnus effect. Such a system for small boats had to either be retractable or swing-away in order to make the system less vulnerable to damage. The retraction of a “normal” fin system is practically impossible, because it takes up too much room inside the ship. Theo found that the Magnus effect cylinders are the answer. To simplify the installation, Theo researched the technology and created a fully electric system. There is nothing technically wrong with a hydraulic system, but it is too expensive and installation takes time and expertise.

Theo and Lambert didn’t just stop at a completely new mechanical and electrical design, they also wanted the most cutting edge electronic control technology implemented into their product. Electronic design engineer Rudolf Geurink was hired to create the best and brightest control system using the latest algorithms.

The new prototype system was built into Theo’s Linssen Grand Sturdy 430 which is a yacht that is 13.5 meters in length. The prototype was tested extensively in all kinds of weather and since then, several systems have been delivered successfully to various types of yachts. Theo and Rudolf now run the company RotorSwing Marine BV.

Quantum, the art off stabilization.

YOUR STABILITY IS OUR MISSION

20 years experience in ship motion control gives Quantum the technical edge in providing military vessel stabilizer solutions. As missions and capabilities evolve at a time of calls for increased efficiency and economy, reduced ship motion means the crew works in greater comfort, greater safety, and with more ability to focus on the task at hand as they expand the mission envelope.

Mark Armstrong will be attending upcoming Military Shows and Conferences.

Link: Quantum Hydraulic - Military Sales

 

[RickB]

As they are 230VAC each and you would have to run the 12 volt DC output of the alternator through an inverter to convert it into 230VAC. After you factor in line loss and inverter conversion loss, 2 of these units that run at a maximum of 1500 watts each will likely consume all of the output of a 240 amp alternator.

Or you could put a thousand thermocouples in your exhaust and power the inverter off that voltage source. Or maybe use a windmill with belts and gears ... there are dozens of really stupid ways to drive the things. Running them off a 12V inverter is just one of them.

If you have a boat big enough to fit active stabilizers, you probably have a boat and budget big enough to fit a generator.

 

[O C Diver]

Or you could put a thousand thermocouples in your exhaust and power the inverter off that voltage source. Or maybe use a windmill with belts and gears ... there are dozens of really stupid ways to drive the things. Running them off a 12V inverter is just one of them.

If you have a boat big enough to fit active stabilizers, you probably have a boat and budget big enough to fit a generator.

Rick, you missed the point.
The point of my post was not to suggest that you should run a set of stabilizers off an inverter, the point was to give a comparison of how much energy they require. My first response was to give the person (post 6) who was asking for something they could more easily relate to. Most of us can grasp the power output of a 240 amp alternator. For some, 3, 000 watts peak power requirement isn't as easy to relate to.

Ted

 

[healhustler]

Ted's right, Rick. I'm one of those stupids. Even if I do get a lot out of your posts, I sometimes need a translator.

 

[FF]

>I've often wondered if trim tabs could be equipped with fast acting cylinders and a motion sensing control to act as roll stabilizers. Bennett has a sensor that will level a boat but I don't think the tabs react fast enough for true roll control.<

MY concept , (mental masturbation only I havent built a boat to try it yet) is a WIDE ,,,, Griffiths style centerboard trunk.

The board would be set to rotate L&R to create the same righting moment as fins.

An electric or air ram would drive the unit.

When not needed or running aground the board would simply pivot up in the well, as CB have been doing forever.

No ripping off or banging holes in the hull, or drag underway when not required .

Cant see any reason it could not work.

 

[RickB]

Most of us can grasp the power output of a 240 amp alternator.

I'll bet a whole lot more can grock the power required to run a waffle iron, a curling iron, a 12kBtu air conditioner, a small microwave oven, a hair dryer, or a Skilsaw.

 

[AusCan]

I'll bet a whole lot more can grock the power required to run a waffle iron, a curling iron, a 12kBtu air conditioner, a small microwave oven, a hair dryer, or a Skilsaw.

I work it out by calculating how many lemons, copper & zinc nails are required.

( 6,171,430 lemons to give us the power of an average car battery)

 

[RickB]

I work it out by calculating how many lemons, copper & zinc nails are required.

Too many variables there ... how ripe are the lemons? How deep is the nail insertion?

I'm kind of fond of thermocouples in the exhaust pipe. You could also make a burner rig to heat another batch of TCs for use when just idling along.

Or maybe a great big solar mirror with sun tracking?

Or, really thinking outside the DC box, why not just install a little generator? The things don't use much power anyway.

 

[Off Duty]

They sound interesting. But for once, i would like to see a promo video of a stabilizing system operating out on rough water; Maybe with a 4 ft beam sea, rather than a 1 foot wake in flat water.

Totally agree!

I just watched the "military" application video and it was frankly rather disappointing. It uses animation to "showcase" the product in a military application. Even then, I've seen more lifelike graphics on kids video games Not trying to be critical, but as mentioned, you'd think that the manufacturer would drop a few bucks in real world testing and recording?

While it looks great in "theory" and on the animation, I wouldn't base a purchase on a poorly done animation (sorry). I would much prefer to see how it's "really" going to work when pressed into service.

OD

 

[FF]

For lower power draws there is always the Soviet Workers Paradise electric.

Short lengths of copper and iron wire are twisted together draped over the chimney and the heat from a kerosene lamp will run a transistor radio..

The good life!

 

[MurrayM]

I'm still waiting for Mr. Fusion to hit the market...

 

[BobH]

Maybe I missed something along the way, but I haven't read a really good description of exactly how these things work. I understand the Magnus effect. But what do the cylinders do in real life? I assume that when the boat is level the cylinders turn very slowly or not at all. When the boat heels, say to port, the port cylinder will speed up to provide lift, an upward force, while the starboard cylinder will speed up but in the opposite direction to provide a downward force. So in this scenario the cylinders will continually speed up, slow down and change direction of rotation.

Is this how it works?

Bob

 

[RotorSwing UK]

RotorSwing Stabilizers

Thank you to everyone for posting your comments on our system, your feedback is very helpful.

To address one or two comments in particular;

1. The power consumption of the system should not be in issue assuming most vessels are equipped with the correctly sized generator. The maximum consumption of the system in underway mode will be 3KW with the average consumption at 2KW, this is very much dependent on sea conditions. If a vessel does not have a sufficiently sized generator it would need to be upgraded at the time of the installation of our system. Compared to installing hydraulically operated fins, the simple upgrade of the generator would be far more straight forward. Both the Chief Designer of the equipment, Theo Koop, and ourselves have many years experience designing and manufacturing hydraulic fin systems for the Super Yacht market and fully understand the complexity and inherent problems of such installations both in terms of installation and ongoing servicing. This is why we concentrated our efforts on producing a fully electronic retractable system with the added benefit of producing far greater amounts of lift force required to stabilize a boat when it most requires stabilization i.e. at zero speed, slow speeds and cruising.

2. With regard to the comment regarding the demonstration videos on our website RotorSwing UK - we completely agree that the best way to showcase the performance of the equipment will be to produce a video of vessels at sea in real life conditions and this is our intention. The videos currently on the site are very much "early days" videos as this system is brand new to the market. We have concentrated our efforts on perfecting the system performance and the video you see on the site was put together in order to have something on the site whilst we work on filming and producing the new video. The "forced roll" video gives an idea of the amount of roll that can be eliminated by the system when operated normally. The amount of roll that can be induced by the system can also be eliminated. In early 2014 you will see our new video added to the site and so please keep checking back. I will post a link when this is available.

3. To clarify how and why this system works so well please allow me to give a brief summary and history.

Having spent the past 30 years designing and manufacturing hydraulic fin systems, Theo Koop has earned a reputation as one of the world leaders in yacht stabilization. Formerly - Theo was behind the well known brand KoopNautic and, having sold this company to Naiad, Theo became part of the team at Quantum Stabilizers who are widely regarded as the market leader in Super Yacht stabilization. When Theo joined Quantum the first ever Zero Speed Stabilization system was designed and installed which changed the way many super yachts have operated for the past 15 years. Quantum has gone on to supply almost 1000 of these systems worldwide on a range of Super/Mega Yachts, military and commercial vessels. Quantum currently holds around 85% of the market share.

In 2008 Quantum was engaged to design and manufacture a system for the worlds largest privately owned Mega Yacht at the time - MY ECLIPSE. Due to the size of fins required for this 160 meter project Theo and Quantum designed and manufactured the MagLift Stabilizer which in essence is a hydraulic version of the RotorSwing system.

Both the MagLift and RotorSwing system employ the exact same principal in order to produce lift forces required to stabilize a vessel - The MagNus Effect. By rotating a cylinder in water - an upward or downward lift force is produced in a similar way to when a tennis ball is hit with top spin or back spin. The amount of lift force that can be produced by the RotorSwing system is far greater than the comparable fin size. The rotor is also installed at a much more efficient angle to the water line resulting in only a 5% loss of lift compared to a typical fin installation which looses approximately 35% of it lift due to its orientation. The result of this calculation on a typical vessel is that the RotorSwing system will be approximately 3 times as effective as fins. A more in depth calculation of this can be found on our website at RotorSwing – A Comparison Calculation Between the RotorSwing and Fin Stabilizers.

When you consider the fact that the RotorSwing system is retractable under the hull to reduce drag at higher speeds where the system is not required as well as being electronically operated the system has major benefits over any other system on the market. We are very confident of this based on our experience and are keen to demonstrate this to the market.

For further information please see our website RotorSwing UK and please feel free to contact me with any questions you may have.

Kind regards

Nick Piper
RotorSwing Uk

 

[RickB]

Welcome Nick, nice to see a manufacturer chime in to help clear the air.

Speaking of air clearing ... let me know if there is an active stabilizer on the market that is not "electronically operated."

They all have a roll sensor of some sort with input and output signal processing, proportional valving, and feedback.

I can't recall seeing any that use a pendulum with a lever connected to a directional control valve and I have been around some iron age systems.