Quantum Stabilizers

Yes, well there's a fair few of us who have used Quantum a lot. Not quite sure what you mean by traditional stabs - are you referring to non-zero speed units? Used Naiad units as well. What do you want to know?

I have seen very few of those Mag Lift Zero Speed Rotary Yacht Stabilizers on vessels in the ship yards in S FL. The vessels I have seen with that system where in the 70ft range. I have not seen or heard of any 150's+ with that system.
I would like to know more myself about that system.

Hi.
Eclipse and Luna have a MagLift stabilizer system. At this link the test for Eclipse:
http://www.quantum-medmarine.com/stabilizers/maglift/

and here the reference list with Eclipse e Luna:
http://www.quantum-medmarine.com/sales/sales-history/

Paolo seemed to answer a few questions there for sure. As I was looking through those links, I started to think of pros and cons between the conventional fin stab and the Maglift. I would have to imagine the Mag lift would consume much less power than the conventional fin set. Then you can have smaller gens saving fuel and additional weight and space.
I would like to hear from some one with real world experience on the Maglift, good, bad, ugly?

Yes, they are supposed to work at low speeds and at anchor.

http://www.quantumhydraulic.com/pages/stabilizers-maglift.php

The biggest advantage of the rotors is that they're retractable:
They can be quite long (and thus efficient) without risking contact with the pier, as they would be retracted when mooring.

On cruise ships, the stabilizing fins retract automatically at speeds below 3 knots, but I guess the captain on a MY with maglift rotors will have to be smarter, or there's not going to be zero-speed stablization.

The gyro's have the advantage of also being effective for boats with very short natural roll periods (typically very light, hard chine boats). This can be more problematic for the hydraulic systems which can't react so fast, but I don't know how the maglift rotors score in this respect.


Bruno

This is true...as far as it goes. The magnus effect rotor system operates in a "sweeping" mode at zero speed and "rotation reversal mode/not sweeping" when the vessel has way on. So, in effect, the velocity of water required to be passing over the rotor(s) when the vessel is lying still is created by the sweeping motion of the rotor(s) themselves.

Pretty sure that there is as video clip on the QME site someone linked to in an earlier post that shows the system working - and basically how it works -in a 3D animation.

You speak of "the discrepancy" as if it is a natural outcome or foregone conclusion of model testing. I vigorously beg to differ.

Can a model test be throroughly mucked up and/or the results improperly interpreted? You bet. Keeps lawyers quite busy when "M/V Rocket Sled" misses her speed target by 10 knots. (apologies if there is any resemblance of that fictitous example to a real vessel by that name. )

But there are very solid and reputable model testing facilities scattered about the world that can repetitively produce very reliable results. Designers and product manufacturers tend to use those facilities when they can.

That simply refers to the fact that with most installations, the rotors will extend beyond the deck or rub rail edge when deployed. The same holds true for some fin stabilizer configurations that are retractable, although those seem to be comning increasingly rare.

Rolls Royce manufactures a couple of retractible models, but I had heard that that they are VERY expensive - the Aquarius and Neptune models. It looks as if the Aquarius model can also set up for at-anchor use as well.

http://www.rolls-royce.com/marine/products/stabilisation_manoeuvring/stabilisers/index.jsp

[QUOTE='roundthehorn] It looks as if the Aquarius model can also set up for at-anchor use as well. ][/QUOTE]


I hadn't seen that before advertised from RR. I notice that feature is only available on the larger models in the product range.

I would be interested in seeing any information, anecdotal or otherwise, as to how well an actual installation of that RR package is working at rest. At-anchor stabilization is becoming more and more common so I guess it stands to reason that RR wasn't going to sit and watch from the sidelines.

In general terms, at-anchor stabilization using fins is "hard on the hardware". First, simply because its typically used for so many more running hours than underway stabilization is, and secondly, because the at-anchor control alorithm involves thousands of high-rate "bang-bang" max-rate fin motion cycles over the full angular range, something almost never seen during routine underway where 'mostly linear' control is being employed. Thus its often the case that a fin manufacturer's at-anchor hardware will be more robustly designed and sized than for a conventional underway-only application.

I'm probably drifting a bit far afield from thread topic....sorry about that. I've dabbled in the field a bit.

RR Fins

We were anchored next to one of the big oceanco's with the on anchor retractable stabilizers. It was not pretty at all. Huge acceleration and very little dampening of the swell.
The system may have been not working correctly, if it was then its not so good.

Oceaneer