We upgraded our Nordhavn N3520 with a stabilizer!

[Magneto]

We are very excited to share our story of being the first Nordhavn 35 to install a stabilizer system.

Not just your typical gyro or fins, but something unique. It’s called a Magnus Master and uses a one-meter rod that spins in two directions under water.
The rod is around 6 inches in diameter and spins up to 1000 RPM both forward and reverse pushing and pulling the water over the surface of the rod causing lift. Enough lift power to dampen or stabilize four-foot waves on the beam.

The boat needs to be moving over 5 knots and our cruising speed is around 8.5 knots which makes trawlers ideal for this application. It does not work at anchor. It performs great while cruising the ocean or ICW.

I love the fact you can deploy and park it in 13 seconds. On the ICW, I keep it parked to avoid crab traps but as soon as a fast deep V-hull starts to pass me, (without notifying his intent on the radio), I have maybe 15-20 seconds before a 3-foot wave rocks our boat and threatens to spill my beer. I now press a button and am instantly gratified by a calmer passing.

In the ocean, so far, we have been out in 3-foot waves on the beam with some following seas. I have no experience with gyro systems so I can’t compare but we are very satisfied with the performance of this DMS system. We can now take the outside in bigger wave conditions than we’ve been able to do without a stabilizer.

The largest selling point to me was the size. Nordhavn 35 has little room for the typical fins or gyro. But it does have a decent storage area in the lazarette and the DMS system will work anywhere placed on the beam under the water line.

I’ve attached some pictures but you can view more details on our website; MVmoondance.com or see the complete installation video on our YouTube channel. I’ll post links below. If you want the technical details, visit dmsholland.com and view the Magnus Master stabilizer.

Also the links to our YouTube channel is:
https://www.youtube.com/@mvmoondance1283

The installation video is at:

https://www.youtube.com/@mvmoondance1283



John & Carol
Moondance N35#20
St Augustine FL.
MV Moondance

 

[Bmarler]

That looks terrific, we’ll done. Any noticeable loss of speed with it?

 

[Magneto]

Only speed loss is about .1 knot
Slight drag to port but not anything that affects fuel burn or steerage.

 

[twistedtree]

Only speed loss is about .1 knot
Slight drag to port but not anything that affects fuel burn or steerage.

Oh, so it's a single rotor? I didn't notice that from the pics.

 

[chanprr]

MagnusMaster Rotor Stabilization

Thanks for the very informative video. The rotor stabilization system is really effective. Currently waiting for my Helmsman 46 to be completed, with tentative arrival in Seattle at the end of March 2024. A pair of MagnusMaster rotors will be installed locally supervised by MagnusMaster techs. Looking forward to many hours of comfortable cruising in the PNW, BC and SE Alaska this summer.

 

[Hippocampus]

Thanks for sharing your experience. Been lead to believe in some applications (two sets of rotors) Magnus effect can decrease pitch as well as roll. Also if all four rotors are generating lift fuel burn goes down. Does anyone have further information.

 

[Pascall]

I have some friends who have had this system installed and are very satisfied with how it works.
This is the second generation as far as mechanics are concerned, the first version worked with a toothed belt and was subject to wear.
The electronics still had a few obstacles in the early days, but this was solved quickly and correctly.
A unique system, especially for small ships, because it takes up little space on the inside and can be placed anywhere.
For our 11.00 meter, 14 ton measuring vessel, an installation of unit is sufficient.

Mvg,

Pascal.

 

[DDW]

Oh, so it's a single rotor? I didn't notice that from the pics.

I had them quote on my boat (slightly smaller at 34') and they quoted a single rotor. The price was significant though. It seems better in most respects for this size boat than fins or gyros - less power than a gyro by far, much simpler and more flexible installation than either fins or gyros, fewer operational problems.

For the OP: do you want to mention the installed cost? Do you ever run it part deployed (at an angle to the beam)? I forget if it is DMS or their competitors product which has this capability.

 

[long-cours.62]

Yes Magnus look good, and people are very réactive...only one problem for us it cost around 70000 euros .

 

[Magneto]

I had them quote on my boat (slightly smaller at 34') and they quoted a single rotor. The price was significant though. It seems better in most respects for this size boat than fins or gyros - less power than a gyro by far, much simpler and more flexible installation than either fins or gyros, fewer operational problems.

For the OP: do you want to mention the installed cost? Do you ever run it part deployed (at an angle to the beam)? I forget if it is DMS or their competitors product which has this capability.

This system will not deploy partially. It does start to stabilizing as it comes out.
As far as the cost goes; long-cours.62 is in the ball park. My marina was double the hours because it was their first but DMS discounted it some to offset. Overall under 80K US is the bogie. If I was do do it again, the experience could shave 10k off of the install.

 

[Magneto]

Yes Magnus look good, and people are very réactive...only one problem for us it cost around 70000 euros .

I just talked to DMS and they are OK with me quoting the US price of around 75K. (Generally)

Like I said in my video, there are a lot of variables that affect that price. I had guys working during Thanksgiving and Christmas.

If your hull can allow a faster build up, glassing and hole cut, you could shave some off. Shipping by cargo vessel instead of air would have saved me a lot coming from Holland.

 

[Action]

Very interesting.

Thank you so much for posting and the you tube vid.

Are single or multiple rotors based on vessel size?

 

[Shrew]

I always thought that that what the sail on a motor sailor is for?

Did you find the sail to be ineffective in reducing roll?

 

[NSM]

Very interesting.

Thank you so much for posting and the you tube vid.

Are single or multiple rotors based on vessel size?

We had a single unit installed on our Helmsman 43E based on DMS’ recommendation. The Helmsman 46 is large enough for two units. It looks like that’s around the break point between single and multiple rotors.

We are currently out of the country and haven’t been on the boat since installation was finalized. Can’t wait to play with it. Will post pictures and videos when we do…

 

[chanprr]

Very interesting.

Thank you so much for posting and the you tube vid.

Are single or multiple rotors based on vessel size?

Single rotor in vessels up to 45K pounds loaded. Our Helmsman 46 will be about 50k pounds loaded so twin rotors recommended, one on each side.

 

[DDW]

I guess it is the SwingRotor one that partially deploys. My quote from DMS was around 50K Euros for the equipment, plus the install. They said single rotor but the actual quote said 2 rotor so confusing - doesn't seem like 2 would be necessary. The SwingRotor was something like 40K Euro plus the install for one. Both required their technicians fly over for the install and commission, which was expensive. That made me a little worried about service should it become necessary, but as they establish a presence here maybe that problem will lessen. I am intrigued with the systems, but have a hard time swallowing the cost.

 

[long-cours.62]

I could even

I just talked to DMS and they are OK with me quoting the US price of around 75K. (Generally)

Like I said in my video, there are a lot of variables that affect that price. I had guys working during Thanksgiving and Christmas.

If your hull can allow a faster build up, glassing and hole cut, you could shave some off. Shipping by cargo vessel instead of air would have saved me a lot coming from Holland.

Pick up them directly to the factory with my small truck
Our boat is in alloy probably easier to fit, may be could use the actual place of our Vetus fins ? ( but not in the "flat" part of our hull ).
The evolution of the cost of stab are ...in 2005 I asked for our "Long- Cours 62" at a well know American maker : 25000 us (including pump, hydraulic tank ) in 2019 I asked for similar equipment for our actual boat ...70000us (without hydraulic pump, and tank who are already on board ) !!

 

[twistedtree]

I'm curious about the asymmetry of a single rotor. You have the static drag of an object in the water on one side of the boat. Plus that drag will increase as the rotor directs force to actively counter roll. I would think it would have a noticeable impact on steering.

 

[Magneto]

Drag effects

I'm curious about the asymmetry of a single rotor. You have the static drag of an object in the water on one side of the boat. Plus that drag will increase as the rotor directs force to actively counter roll. I would think it would have a noticeable impact on steering.

I answered this question from James B Frantz but it may have been in PM / email but deserves answering.

My mileage is about 1.2 mpg at 2000 RPM and at 8.5 knots.
There is a .1 knot drag when deployed. Not very significant but it adds up.
Round it all off; a tenth of a gallon times 10 hours = 1 gallon cost per day of stabilization.
Not all things are always equal and we usually run only 7-8 hrs a cruise. But winds and currents may bring my burn at 1 mpg so shooting from the hips I would stay with the 1 gallon per day of cost. The slight drag to port does not affect us much because autopilot takes care of it. I only notice it when I am manually steering and I deploy it. The boat tracks a little to port but comes right back when deployed.

I do need to say that this was in the specs and we have not measured enough time cruising to say that this is 100% accurate.
But you do give me reason to measure exactly and let everyone know.
We are mooring in Key West for a month now and won't have that data until mid February.

You have given me another action item on my list.
I need a retirement from my retirement.

 

[rslifkin]

I'm curious about the asymmetry of a single rotor. You have the static drag of an object in the water on one side of the boat. Plus that drag will increase as the rotor directs force to actively counter roll. I would think it would have a noticeable impact on steering.

Even if the effect isn't noticeable, the asymmetric design would bother me in concept. For smaller boats I'd rather see 2 down-sized rotors vs the 1 standard size one. But I'm not sure these come in multiple sizes.

 

[CharlieO.]

Even if the effect isn't noticeable, the asymmetric design would bother me in concept. For smaller boats I'd rather see 2 down-sized rotors vs the 1 standard size one. But I'm not sure these come in multiple sizes.

Definitely makes my OCD flare up.:lol:

 

[twistedtree]

I answered this question from James B Frantz but it may have been in PM / email but deserves answering.

My mileage is about 1.2 mpg at 2000 RPM and at 8.5 knots.
There is a .1 knot drag when deployed. Not very significant but it adds up.
Round it all off; a tenth of a gallon times 10 hours = 1 gallon cost per day of stabilization.
Not all things are always equal and we usually run only 7-8 hrs a cruise. But winds and currents may bring my burn at 1 mpg so shooting from the hips I would stay with the 1 gallon per day of cost. The slight drag to port does not affect us much because autopilot takes care of it. I only notice it when I am manually steering and I deploy it. The boat tracks a little to port but comes right back when deployed.

I do need to say that this was in the specs and we have not measured enough time cruising to say that this is 100% accurate.
But you do give me reason to measure exactly and let everyone know.
We are mooring in Key West for a month now and won't have that data until mid February.

You have given me another action item on my list.
I need a retirement from my retirement.

Thanks. I ask because I know with fins if they are not adjusted properly you get asymmetric drag, and under various conditions it can raise hell with AP steering.

 

[Magneto]

Even if the effect isn't noticeable, the asymmetric design would bother me in concept. For smaller boats I'd rather see 2 down-sized rotors vs the 1 standard size one. But I'm not sure these come in multiple sizes.

I can see that but there is no down size. It would cost you twice as much for that asymmetric value. I could let a few barnacles grow and make more of a difference in drag than one of these.

I have talked to people putting on two of these on boats less than 50 feet. I think its over kill for the expense and now you have two crab pot catchers.

 

[cafesport]

Magneto, Thanks for being the test pilot on this.

In your case you have a true single engine boat with asymmetric prop thrust which always pushes the boat to starboard. Many nordies have an additional offset starboard wing engine, and I suspect this may have a greater effect than the magnus rotor, which in your install is actually canceling the push. According to you increased fuel use this is apparently 1.8 hp or about 1350 watts of energy.

It’s tough to say if this extra fuel use is from increased drag or from the efficiency losses in the power system design. Using an alternator to create dc power and inverting it to 2500 watts to power what appears to be a 2hp motor ac motor has a cost too.

.

 

[DDW]

I wish one of these companies would market a system that was pictured here on the forum some time ago. It consisted of two rotors, they were simply hung from the transom into the wake, one on each side outboard, fixed with no articulation. The owner said they worked well. The company that made them is no more (or makes them no more). An improvement would be to make them retractable above the transom corner.

It would be a far simpler mechanism, more robust in the event of striking an object but in any case not as likely to strike, and a lot cheaper to install.

 

[Seas_the_day]

This is a new and mind-expanding concept for many.

The DMS MagnusMaster rotor stabilizer is very effective in anti-roll stabilization while underway at trawler speeds, and the performance of the single rotor MagnusMaster on NSM's Helmsman Trawlers 43E is impressive.

DMS Holland, in partnership with Waterline Boats, will be at the Seattle Boat Show Feb 2 - Feb 10. Anyone can visit the booth to see a rotor unit in person and to speak with the experts from DMS.

 

[PNK]

Magnusmaster for trawlers

The November/December issue of Passagemaker had a good article about the Magnusmaster system, which was pretty helpful in understanding how it works. It also had links to the manufacturer's web-site, where they have a tool to figure out what size is needed for a particular boat. Supposedly Elling, Helmsman and Nordhavn now offer it as an option on new boats; there may be others as well.
I have been pretty disappointed with Passagemaker recently, which used to be full of interesting technical discussions, and reviews of boats that pointed out both the good and the bad, but now they mostly seem to be an advertisement for boats that few of us will ever be able to afford. This particular article, though, was pretty good.
It has some advantages over larger active fin or gyro stabilizers, but also the disadvantage of not working at anchor, or at very low speeds. The company's web-site is "dmsholland.com"
Peter

 

[Rsysol]

Only speed loss is about .1 knot
Slight drag to port but not anything that affects fuel burn or steerage.

Thanks for the post, they also estimated around $75k for a dual rotor installation on our steel hull. Nice to see this product taking hold in the states.

 

[Circumnavigator]

That's more than twice the price of the Quick gyro we installed in Morning Light, which is a 42' Webbers Cove single screw trawler displacing 38,000 pounds. The gyro has nothing outside the boat and can be installed anywhere you have a cube two feet on a side. It does require 3kW at 120 or 240VAC and is simpler mechanically -- effectively only two moving parts. It works at any speed, including at anchor and does not slow the boat. And, of course, it runs all the time you need it -- no turning it on and off for fear of pot buoys.


Jim

 

[DDW]

Each stabilization method has its pros and cons. A gyro takes a lot of power and a long time to activate. Also very heavy, and maintenance can be expensive. A gyro puts a big hole in the boat with a stick attached to it. There are versions that work at anchor. In theory, the Magnus should be manufacturable for a lot less than the currently offered versions suggest.