Experience with zero speed stabilisers from different manufacturers on large yachts??

[BIGBOATBUILDER]

Hi, even though this might start a battle, I'd be interested to hear what your experiences with zero-speed stabilizer systems of the various manufacturers are.

I'd be especially interested to hear about quality, service and reliability from manufacturers like:

-Quantum
-TRAC / American bowthrusters
-Wesmar (I think they are just about to bring a zero speed system on the
market)
-Rolls-Royce
-Najad / Vosper Thornycraft

Thanks for your help,

Franzi

[CTMD]

I always specify TRAC and have never heard a complaint. Depending on the speed of your boat, they do some nice interceptors now too as an alternative to trim tabs.

[BMcF]

Being 'somewhat familiar' with the development of the first 'zero-speed' fin systems, I would offer this; When the algorithms were proven and control effectivenes of the first 'at anchor' systems was borne out in practice, there was a rush to retrofit the controls to quite a few existing systems, keeping the existing fins and hydraulics in place. Two things became evident rather soon after that flurry of upgrade activity:

1. The existing fin hardware was not up to the task of supporting the rapid and non-linear 'zero speed' fin activity without suffering from inadequte hydraulic capacity and/or rapid wear-out of fin hardware.

2. Fins (and top plate design and actuation capacity) that were specifically taylored in planform, stock location, etc. to provide more effective zero-speed control were developed and perform far better than the typical/standard roll fins for that application.

So I guess my short answer would be "beware of those offering the same fin hardware as they always have but now claiming that they can include zero-speed control option with it". It may be so - I'm not familiar with all of those you mentioned and would rather not go in to the details of those that I am quite familiar with. Just a little background that might be useful as you ask each potential supplier to address the 'hard questions' relating to proven performance and proven reliability.

Edit: Note that interceptors cannot perfrom zero-speed control. Trim tabs can, in some cases, but nobody yet offeres, to my knowledge, an off-the-shelf solution for zero=speed control based on the use of active trim tabs. We've done it only on a custom and test/trials/R&D basis.

Note also that Quantum offers both fin and Magnus-effect rotor zero-speed control systems..or combinations of the two technologies.