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Old 02-28-2020, 05:08 PM   #41
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Originally Posted by Gotwex View Post
That's my boat!...

I've never seen that design before. Do you know the manufacturer?
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Old 02-28-2020, 07:18 PM   #42
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You stated you looked at various fins from Naid and others, but found them ďvulnerableĒ. Are you saying that large L shaped thing sticking out of the hull in the first photo is less vulnerable than a Naid fin?

Regarding Seakeepers, agree, you need internal space for it. We had a large empty spot in the aft portion of the engine room and it fit in there well. As far as start up time, it takes about 30 mins for it to spool up to engagement speed. Not a big deal, I just start it at the dock prior to leaving while on shore power and shift over to the Gen, or start it on our way out and itís ready to go. Spool down time down is about 4 hours and itís a non issue. The raw water cooling pump for the antifreeze heat exchanger runs about 15 mins, then shuts off. It just slowly winds down on its own, and the noise is barely audible. Not saying the Seakeeper is a better system because I donít know anything about the one you are referring to, but I find people on TF have some opinions about Seakeepers and have little to no interaction with them except for what they heard second hand on the docks.
Agree with the above on all counts. The Magnus is retractable, so perhaps slightly less vulnerable, but then again you need to incorporate its "garage" into he hull, which itself could pose a vulnerability and, how strong is that garage if the fin were to strike something underway? What puzzles me is why this system has not caught on more, if it works as well as the manufacturer claims it has clear advantages, and it's been around for 15 years.

I'm curious, did you test the system on another vessel before committing, or are you relying solely on a boat show demo?

A few months ago a client of mine was encouraged by the manufacturer of the boat he's having built, to use the new Humphree electric fin stabilizer. He asked me about it and I agreed that on paper it looked very attractive, however, until I tested it, on a boat, in open water, I could not render an opinion. Humphree said they had installed it on many boats, mostly in Europe, so none were readily available for a trial in the US. Just last week I was finally able to test it at the builder in Asia. While it had some issues, which I believe are software related, when it worked, it worked well. While you can review stability graphs, there really is no substitute for a real-world test (be it a stabilizer system, forward looking sonar or noise reduction system), boat shows are far from the ultimate proving ground.

As far as gyros go, like everything else there's no free lunch, Seakeeper's longer spool up and down time is a function of its high rpm, which in turn is made possible by the fact that it operates in a vacuum. The high rpm makes it more effective for a given footprint. Competing gyros are less expensive because they don't operate in a vacuum, and as a result they turn more slowly, and spool up, and down more quickly, but are less effective for a given footprint. The Seakeeper and some other gyros also pivot on an axis, which enables them to effectively turn off, to allow a vessel to right itself if it does roll. Unlike fins, gyros do not correct roll, they simply resist it, an important distinction. Not all gyros incorporate this feature. Without it, if the vessel does roll, it's slower to return to an even keel. And without it, the gyro is smaller and less costly. Thus, you must weigh cost, vs. size vs. effectiveness.

Seakeeper recently introduced a gyro suitable for small center consoles, that was the founder's (Shep McKenney) dream from the very start, mass production of small gyros for small boats. For more on the company's origin see https://stevedmarineconsulting.com/w...eper113_06.pdf

Of the three new build projects I've been working on over the past two weeks, two have Seakeeper, one Humphree fins. Both offer advantages. I've tested Seakeepers extensively, they work, of that there's no doubt. Do they have shortcomings? Of course, show me a complex marine system that doesn't. The Humphree fins are intriguing at the moment, compact, no hydraulics, and take up little room on the inside. Only time will tell how they work and hold up long term.

Once you take delivery of the vessel I suspect we'll all be very interested to hear how well this system works, how reliable and how quiet it is. Like others have suggested, I would carefully assess the power requirements, to ensure the vessel can support them, at rest, for the duration of time you'd like to have a quiet ship.

(In Singapore, bound for Taiwan)
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Old 09-22-2020, 09:57 AM   #43
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At last

The Magnus stabilizers have been installed on my ST 52. (At last I would like to say) First Mr. Blu was transported from Split (Croatia) to Rotterdam by Starr Class carrier. I used them before to transport our President 385 to and from Croatia, so the drill was rather familiar for me. Only COVID-19 made things more complicated. I was not allowed to travel to Croatia and further it was not allowed to do recreational boating in Croatian waters.
But everything was handled by the agent in Split.
We were lucky that the lock down had ended when Mr. Blu arrived in the Netherlands, so we could transport her/him to the Kerkdriel where the stabilizers were to be mounted.
After they had started a lot of time was used in waiting that the reinforcement of the hull had dried and was strong enough to mount the stabilisers.
As pictures tell more than a thousands words can say, I have made some photoís.
After a test drive I discussed with one of the engineers whether the (standard) inverter of the ST 52, a Mastervolt 24/2500 was sufficient for the job. Although it can meet with maximum demand of the Magnus Master system, I decided to stay on the safe side and replace it by a Mastervolt 24/5000 inverter. We tested on a rather quit river under good weather circumstances and it would a pity if, at sea and under bad weatherconditions and using perhaps other appliances the 24/2500 could not handle the job and the Magnus Master would stop. So for a few euro's more....
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Old 09-22-2020, 10:00 AM   #44
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And more

A few photo's more
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Old 09-22-2020, 10:07 AM   #45
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Copy, I noticed that in the other photo and edited my response. My original question regarding the OPís assertion that itís less vulnerable than Naiad fin still stands.
Regarding to the fins I have the idea that pushing the water away costs more strength than creating the uplift / downlift by the rotating tubes of the Magnus system.
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Old 09-22-2020, 10:23 AM   #46
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To answer a few questions that have been raised.



The Magnus Master system only is effective as the boat moves. If you put your throttle in neutral the tubes immediately fold toward the original position. If the speed of the boat exceeds 12 knots the tubes are also retracted.



If you activate the MagnusMaster system, it nearly immediately is effective. Just one push on the screen button.



Noise: As the engines are running you cannot hear the system. It is electrically driven.


The system is controlled by a small screen on the steering stand. Very easy to use.


About drag: I have two Volvo Penta D9-575 engines with in total 1150 HP on board. It makes about 0,5 knot difference when I use the tubes. Nothing to worry about.
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Old 09-22-2020, 10:34 AM   #47
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Regarding to the fins I have the idea that pushing the water away costs more strength than creating the uplift / downlift by the rotating tubes of the Magnus system.
I would question that, as the lift/drag ratio of Magnus tubes is lower than a good airfoil. But it is an intriguing system for a lot of reasons.

Can you say what the approximate cost of such an installation is?
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Old 09-22-2020, 10:58 AM   #48
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I can quote from their price list from 2020 to give you an idea: 2 tubes 140/1000 rotorsystem excl taxes and exclusive installing costs:
€ 45.000/US $ 53.000 ($ 1,1711 = 1 Euro) For GRP yachts you will need special cans to be laminated and I had a Speed Interface. Approximately € 3.500/US $ 4.000.


They write in their documentation that no hydraulics are required. The system is maintenance free. Something that the gyro systems cannot guarantee. They need cooling by seawater and require regularly maintenance. Also the spooling up time that we experienced in a demonstration of the SK didnot make us happy.


But the most appealing to me was that MagnusMaster requires little space in building it in afterwards. For the Seakeeper I had to sacrifice at least the watermaker.



But that is always the case with secondhand boats. They are always a compromis. But on the other hand you buy much more boat for less dollars.
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Old 04-27-2021, 01:48 AM   #49
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A short update on the Magnus stabilizers..

I was able to test the Magnus system for the first time in real two weekends ago. We had to take Mr. Blu to Friesland (a province in the northern part of the Netherlands). Due to Covid-19 we had to go across the IJsselmeer which is renowned for its nasty seas in windy conditions. The IJsselmeer is not so deep ( approximately 4-5 meters) which can cause special waves. The wind conditions that weekend were 6 to 7 Beaufort with gusts up to 8/9. The stabilizers kept the ST 52 in a straight line. My crew members (who knew what they could expect on the IJsselmeer with 6/7 Bft) were very impressed by the effect that the stabilizers had on the performance of Mr. Blu. It has met all my expectations. Especially the time to get the system in operation. Just push a button on the small touch screen and the system starts. No more then 10 seconds.
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Old 04-27-2021, 02:34 AM   #50
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As for contacts in the USA. I learned from their website that they have recently an agent in Florida, Fort Lauderdale https://www.dmsholland.com/contact/dms-world-wide/
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Old 08-22-2023, 09:22 AM   #51
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anyone else put other types of stabilizers on the st52?
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