Magnus Master stabilizer vs Gyros

[jj42]

Hi,

I'm look at different stabilization options for a displacement/semi displacement boat ~40ft (retrofitted).

One option is a Seakeeper Gyro and the other is a DMS Magnus Master (requires ~ 3 knots to start working).

As far as I can tell they are similarly priced.

+ Magnus requires less room inside the boat.
- Magnus doesn't work at 0 speed.

I would be interested to hear experiences and views about how they compare at displacement speeds.

 

[Deleted User YDKXO]

I have no experience of the Magnus system but I did retrofit a Seakeeper gyro to my 63ft planing boat 2yrs ago so I have some experience of that. You need to ask yourself 3 questions. First, is your boating long distance passagemaking or, like the vast majority of boaters, short distance coastal cruising? Second, how much time do you spend at anchor typically? Third do you have the space inside your boat to fit the systems you are considering and a means of powering them?

These are my thoughts on the Seakeeper gyro in my boat. It works excellently at zero speed but loses its effectiveness the faster you go because it cannot overcome the increasing hydrostatic forces acting on the hull. At 10kts and above on my boat it has no discernible effect. It takes about 45mins to spool up which means you can't switch it on when you need it. In fact, I start powering up the gyro before I even leave the marina. The other big factor to consider is that the gyro needs mains power which means that you need a generator to power it and that generator will be running continuously whilst you have the gyro on. I had my generator overhauled before I fitted the gyro knowing this and now I put far more hours on my generator than I do on my engines. On the plus side, the gyro itself is very quiet and, unlike other stabiliser systems, it can be fitted pretty much anywhere inside your boat although I fitted mine in my engine bay because I had the space

In your position, I would be thinking like this. First I would discount any kind of stabiliser system that doesnt work at zero speed because there are so many proven systems out there that do. If my boating was mainly coastal cruising with many days spent at anchor, I would be considering a gyro because its going to work 100% at anchor when you probably want it the most and give you some stabilisation at displacement speeds. On the other hand, if I was doing long distance passagemaking I would be considering hydraulic or electric zero speed fins which will give you optimum stabilisation at speed but can also be used at anchor. The downside of fins of course is that they need to be positioned correctly in the hull which may conflict with existing machinery or furniture and of course you need to make a hole in the hull and probably strengthen it at that point. With hydraulic fins you will also need hydraulic motors fitted to an engine and generator which, again, may not be so easy

 

[BartW]

on a D and SD boat I would recommand fin stabilisers,
have a look at CMC marine, they have a new compact electric system, (aimed at boats sub 80ft), that can run from battery's.
ideal for retro fitting,
CMC will advice on performance, and best position to place them on your boat,

6y ago, we have retro fitted CMC stabs on our boat, the slightly older and bigger system
we run the system with two 8KW invertors, Afaik we have the only 75ft boat that can run stabs from batts, and I assure you that we did that during many hours
still a very happy user !
here is a report from the retro fitting, starting from post #610
http://www.ybw.com/forums/showthrea...)-Rebuild-thread/page61&highlight=stabilizers

 

[Deleted User YDKXO]

have a look at CMC marine, they have a new compact electric system, (aimed at boats sub 80ft), that can run from battery's.

Thats an interesting development. For me, stabilisers which can be run from a battery bank whilst at anchor is a major plus