Anti-Rolling Gyro or Stabilization Fins

Here's a press release on the ARG...

http://www.yachtforums.com/forums/n...popular-science-award.html?highlight=arg+gyro

It's not a new technology, but a new application of the same. It's a mechanical gyro that for all practical purposes, should produce better "static" results than traditional fin stabilizers, i.e. at anchor or docked.

As for anti-roll properties underway, I'm sure it adds a level of stabilization, however I don't believe it would be as effective as active fin stabilization, especially as speed or wave height increases.

The combination of both systems would produce the best results, however this would be expensive and would add additional weight. The added weight of the ARG is not be a bad thing, as this can improve stability at speed or at rest, given it's low CG placement within the hull.

The real upside to the Mitsubishi ARG is simplicity, as this removes hydraulics, plumbing or servo motors from the equation. It also means nothing is protruding from the hull, which decreases drag and eliminates the possibility of damage due to protruding fins.

I think the best person to contact, with respect to answers and feedback, would be Tom Houliaries, vice president of Marine Max. Tom is one of my oldest friends and he was interviewed on the ARG in this Popular Science article...

http://biz.yahoo.com/prnews/051110/cgth025.html?.v=34

PM me for contact details. I don't like to post e-mail addresses or phone numbers on the forum because of webcrawlers.

ARG matey

VIDEO OF ARG

There is a great video on Ferretti's web site demonstrating ARG. They show you video of before and after. It is pretty amazing technology.

www.ferretti-yachts.com

go to MENU (bottom right corner) > NEWS AND EVENTS > VIDEO GALLERY

In viewing that clip... I would have to concur, sir.

Which prompted me to take a second look at the image supplied in the link above, seen here...



It wouldn't be difficult to create this imbalance if the boat on the right was swinging around the transom of the boat on the left, pulled a fast stop, add a little port bow thruster, reverse a gear and... voila! One could also question "why" the boat on the right has been presented with an instability, when the surrounding conditions appears to be calm.

Not insinuating this was done, by any means. Just speculating on how this could be staged. That being said, Mitsubishi is a reputable company and I'd be hard pressed to believe they would gear up for production if the unit didn't offer some benefit. To what degree... remains a question.

Sorry to refer to these Custom Lines as boats. Just using them for reference.

Gyro vs. fin stabilizers

Hi all,

I'm doing a bit of research. I was wondering if you could tell me what the functional difference is between high-end, zero-speed fin and gyro stabilizers. If price was no object, which would you choose, and why? Is one better than the other in port or while underway? Is one hardier than the other - why exactly are zero-speed fin stabilizers so much more expensive than gyro systems like Seakeeper or ARG?

Thanks a lot! (And I'm sorry if this discussion has already been had... I couldn't find it if so!)

The functional difference is one uses fins moving water for stabilization and the other has a very fast spinning gyro attached to the hull on the inside of the bottom for stabilization.

I have not used the gyro system yet myself. But I really like the concept and have research them for a friends new build and perhaps to retro fit on the boat I'm currently on. After checking them out my friends boat owners are going to use them in their new boat.

As to why there is such a large cost difference between the two, I'm not sure. But as I recall you could get two Seakeeper systems for the cost of a Zero Speed upgrade to an existing system alone.

As I mentioned, I like the gyro concept. No fins sticking out to hit or catch on anything. Less drag. And no bearings or leaky seals to deal with or replace from time to time.

I had the Mitsubishi ARG's on my Ferretti 630 & have to say that they did make a difference when switched on. It took approx. 20 mins to spool up to full speed but worth the wait. The could be used at anchor or while underway.

The other difference Capt. Bill11 has not mentioned is that (in my understanding) the fin type can only be fitted on large yachts due to the amount of hardware involved.

Thanks for the prompt answers, folks. Much appreciated!

My research entails looking into Riva vs. Wally; any insights more generally? Which would you choose if you had to buy one or the other, and why?

Mitsubishi ARG test ride

I got the chance to ride on a bertram 70 the other day. it had the mitsubishi stabilizers installed. what a difference it made! When up on the fly bridge it was so steady we could have made breakfast if we had a grill! Down below where they were running they just sat there, no moving parts, safe as could be. This is going to become standard equipment someday!

In a recent issue of Power and Motoryacht, there was an article about one of these gyros installed on a charterboat fishing out of NJ (I think). Quite interesting. Although one of the long-time captains was skeptical, he was quite surprised at it's effectivness.

Don't count on it. A mechanical gyro will never replace active fin stabilization. While a single axis spinner can offset roll momentum/acceleration, to a certain degree, it can only react to motion. It is not able to provide a continuous counter effect in the same way as subsurface fins with water passing over them.

Because these gyro based systems are one dimensional in nature, they can only provide anti-roll assistance. They can do nothing to counter pitch, whereas stabilization fins, such as Quantum and others, can do both. That said, the latter has been geared toward larger applications and isn't always suitable for smaller apps.

Another potential issue is longevity of gyro-based systems. We really don't have much long term data on reliability. And while you might call me skeptical, gyro reliability in other apps has been known to be spuratic.

As for these units becoming standard equipment, not at their cost and weight penalty.

I guess these Gyro's have to be installed on the centre line midships, or could you install one off centre?

Where the gyro is mounted isn't as critical as keeping the center of gravity as low as possible, in effect using the weight of the gyro as ballast. They are typically mounted in the bilge, aft of the engines and between the drive shafts. Not a very friendly environment for a precision instrument. While the optimum mounting point should be closest to the center of rotation, in reality the best place to mount a heavy, mechanical gyro is closest to the greatest mass.