Click for Westport Click for Mag Bay Click for Ocean Alexander Click for Lurssen Click for Walker

Gyro Stabilizers for mid-sized yachts

Discussion in 'Stabs, Tabs & Gyros' started by Viceroy, Jan 15, 2020.

You need to be registered and signed in to view this content.
  1. mapism

    mapism Senior Member

    Joined:
    Aug 9, 2008
    Messages:
    591
    Location:
    Sardinia
    That's nowhere near as interesting as your interpretation of what I wrote.

    From my post #9:
    Just about every fin stabilizers I tried were very comparably effective, when properly sized and commissioned: Naiad, ABT, CMC, Wesmar, Sleipner (also before their "Vector" stuff).

    From my post #14:
    I've been on boats equipped with ABT and CMC zero speed (straight) fins, whose performance at anchor was totally comparable with curved fins.

    Now, is my English really so bad to not understand that in the second sentence I only mentioned two other brands because they are the ones which I considered on par with Sleipner's curved fins?
    That said, I already mentioned that when it comes to personal experience, mine is as good or bad as anyone else's.
    So, if yours is difference than mine, fair enough, who am I to argue?

    What I find annoying is how frequently in these debates folks seem more interested to shoot the messenger rather than actually debating the subject.
    Is that a Southern Florida thing, I wonder?

    PS: ref. the tests that Sleipner ran on a Princess (56, as I recall), they were indeed published on their website, already back in 2013.
    But promptly removed not long afterwards - why, that's anyone's guess.
    Regardless, I was talking of proper independent tests, which shine for their total absence, up to current days.
  2. olderboater

    olderboater Senior Member

    Joined:
    Sep 2, 2013
    Messages:
    5,979
    Location:
    Fort Lauderdale
    Have you actually run a boat with Sleipner vector fins? That's the only one I indicated, or meant to indicate, you lacked experience with because no where do you mention having such. Now, I don't have experience with many of the brands you do, but I do with that, about 10,000 nm worth with vector fins. (I have more experience in total with Naiad than any other and no experience with Wesmar or CMC). I was not a believer until I ran them. And, for the record, Capt J didn't believe me until he ran a different model with them.

    As to the Princess data, it wasn't removed until they redid their site about 2 years ago. I don't know the reason either and won't speculate.

    I also made it clear when linking to their site, that it was advertising on their part and clearly prejudiced as such, but an explanation from them of the advantages, advantages I have experienced on the water.

    I also did not argue that any zero speed wasn't comparable to Sleipner at anchor. I only stated that Gyro wasn't comparable at speed and non-Zero speed might not be comparable at anchor.
  3. Pascal

    Pascal Senior Member

    Joined:
    Feb 29, 2008
    Messages:
    5,483
    Location:
    Miami, FL
    Spin up time is often mentioned as a downside of gyros but in the real world does anyone really hop on, gets under way and reach rough water quickly enough to need stabilization before the gyro is up speed? especially since when anchored out you likely have the gyro going

    now an issue which I have never seen mentioned is the amount of power needed. Zero speed only requires an electric motor running the hydraulic pump. A gyro requires a lot more power doesn’t it? So chances are you will need to run a second generator or limit power usage (shut down one chiller, watermaker and limit cooking). I know that we are always close to the limit with a full house...
  4. mapism

    mapism Senior Member

    Joined:
    Aug 9, 2008
    Messages:
    591
    Location:
    Sardinia
    When I said that I tried Sleipner stabs, I specified "also before" their vector stuff.
    By implication, I hope you'll agree that this means both their flat and curved fins.
    Not for 10,000 Nm, admittedly - far from that.
    But I struggle to understand what this has to see with understanding their effectiveness at zero speed... o_O
  5. olderboater

    olderboater Senior Member

    Joined:
    Sep 2, 2013
    Messages:
    5,979
    Location:
    Fort Lauderdale
    You are correct. "Also Before" does imply both. I have no experience with the "before."
  6. mapism

    mapism Senior Member

    Joined:
    Aug 9, 2008
    Messages:
    591
    Location:
    Sardinia
    Well, they were/are also very good, both underway and at anchor.
    I'm not saying just as good as the vectors, because that would be a bold statement, to be supported by some tests/measurements.
    And as I said, I'm not aware of any reliable independent tests on this matter.
    But pretty sure, if a difference exists, it's very far from being immediately perceivable from anyone onboard.
    In fact, several other folks who were with me, some of which with a much more extensive experience than myself, all agreed on that.
  7. Viceroy

    Viceroy Member

    Joined:
    Dec 27, 2005
    Messages:
    62
    Location:
    Semi-retired in Sidney, British Columbia
    For what its worth at this juncture, I am slowly working through the web and personal contacts trying to sort out succinct information on the types, applications and installation of Gyro stabilizers. There are some cavalier opinions about "just dropping a unit anywhere" with some strengthening in the hull stringers. And a recurring issue are the costs of installation in existing hulls. So far I have made some cursory examinations of five manufacturers stretching from America to Europe to Asia. When the day comes to offer any useful advice or direction, I'll chime up again. Cheers, Richard.
  8. mapism

    mapism Senior Member

    Joined:
    Aug 9, 2008
    Messages:
    591
    Location:
    Sardinia
    Beware of those!
    Though in fairness, also retrofitting fins to a hull not originally designed for them can be tricky.
    Neither their placement nor hull strenghtening around the actuators should be taken lightly.
    Looking forward to hearing about your next findings!
  9. wiredup

    wiredup Member

    Joined:
    Jul 20, 2016
    Messages:
    32
    Location:
    va beach
    I am adding 2 sea keeper 6's to my boat right now. I too was concerned about the power needed and how that affects my existing generator's capability. What I was told was to power them up (which is when most draw occurs) while hooked up to shore power, then switch to generator and I should be fine. I have one 21kw onan. It takes 45 minutes for that to occur. I will find out soon enough if I have to add a second generator, hopefully not.
  10. mapism

    mapism Senior Member

    Joined:
    Aug 9, 2008
    Messages:
    591
    Location:
    Sardinia
    Is whoever suggested that you might need it a genset seller, possibly? :)
    The max absorption of the Seakeeper 6 is 2300W according to the manufacturer's specs, i.e. 4600W for two units.
    A 21kW genset should handle that with no sweat from the start, unless you want to run also A/C or whatever at the same time....
  11. wiredup

    wiredup Member

    Joined:
    Jul 20, 2016
    Messages:
    32
    Location:
    va beach
    No, actually the yard said I should be fine. I do have 5 ac compressors, so I might have to leave one or two off.
  12. alvareza

    alvareza Member

    Joined:
    Aug 20, 2010
    Messages:
    80
    Location:
    Boston MA
    A single Seakeeper 6 works fine on my boat with a single 10kw genset. Even with water heater, ac etc on during startup.

    I sometimes start the Seakeeper on dock power if I have a particularly seasick prone guest joining us. No rocking from the beginning makes a difference.
  13. Fishtigua

    Fishtigua Senior Member

    Joined:
    Jul 20, 2007
    Messages:
    2,696
    Location:
    Guernsey/Antigua
    Mapis, do you remember that 16oft yacht getting refitted in Toulouse a couple of years ago? Selling 2 gyro's off at half price because the yard's design engineers ordered them way too small and they did nothing. I think they lost $35k on each one.
  14. Capt J

    Capt J Senior Member

    Joined:
    Jul 11, 2005
    Messages:
    12,787
    Location:
    Fort Lauderdale
    You should be ok on generator. I'd be more worried if you have a single 50 amp shore cord and all 5 a/c's running. Flipping off the water heater and an a/c while they're spooling up should keep amps low enough. However, usually you're starting the seakeepers fairly early in the morning and not all 5 a/c's are cooling yet anyways.
  15. mapism

    mapism Senior Member

    Joined:
    Aug 9, 2008
    Messages:
    591
    Location:
    Sardinia
    Nope, can't remember to have heard of it.
    But I have a funny feeling that they probably wasted another similar amount also on manpower.
    Just think of installing and afterwards removing (in a finished boat!) those things, plus installing something else (fins, I suppose?) afterwards... :eek:
  16. wiredup

    wiredup Member

    Joined:
    Jul 20, 2016
    Messages:
    32
    Location:
    va beach
    I have the ability to add a 2nd shore power cord, and may do that during the hottest parts of the summer. I often have AC's running, plus Ice maker, water heater, etc.
  17. Capt J

    Capt J Senior Member

    Joined:
    Jul 11, 2005
    Messages:
    12,787
    Location:
    Fort Lauderdale
    You won't (or shouldn't) be running seakeepers at the marina aside from right before you go out. I really don't think it's a problem if you simply keep an eye on electrical draw while they're spooling up and maybe shutting the water heater and 1 air conditioner off. The generator should handle everything (a/c's, water heater, etc.) once the seakeepers are spooled up. If you want to add a 2nd cord, you always could, but I don't think it will be necessary if you just keep an eye on loads. Generator should handle startup time of seakeeper and all a/c's. So could always just get on Generator early. Plus, there are many times I get the seakeepers started at the dock, but leave the dock well before they're ready because I'm in calm water idling out (Intracoastal etc.) anyways.