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Old 03-27-2015, 06:17 PM   #21
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Unless I missed it in this thread, I did not see mentioned that the gyro takes 40 minutes or so to reach speed. Plan ahead for beam seas!
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Old 03-27-2015, 07:42 PM   #22
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The Seakeeper website is replete with information. This is not an experiment on Kevin's part, Seakeepers are the real deal with over 2000 in use on craft big and small. Google them at:

www.seakeeper.com
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Old 03-27-2015, 10:11 PM   #23
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Unless I missed it in this thread, I did not see mentioned that the gyro takes 40 minutes or so to reach speed. Plan ahead for beam seas!
Don't people do that in general? Plus the extra time you take to let the system warm up pays off once you anchor up in that anchorage at the end of the day that no one else can use but you because of the surge or swell that would have them rolling all night but your the one enjoying a comfortable meal and nights rest.

Once you have at rest sabilization it can open up a whole new world of anchorages.
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Old 03-28-2015, 12:01 AM   #24
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Does anyone here have them on their boat, or will Kevin be our guinea pig? I'd love to hear some first-hand owner experience. There is plenty of fin stabilizer experience out there, but so far no gyro that I've heard. If there are really 2000 of them deployed, where are the customers?
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Old 03-28-2015, 02:29 AM   #25
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Does anyone here have them on their boat, or will Kevin be our guinea pig? I'd love to hear some first-hand owner experience. There is plenty of fin stabilizer experience out there, but so far no gyro that I've heard. If there are really 2000 of them deployed, where are the customers?
Wait a minute!!! You've got me already installing the thing

I do not know who all the customers are. I do not know if the little one is the proper size for my boat. I do not even know for sure if my boats hull type is proper for the unit. Remember I have a fiberglass hull with a foam core. It has two nice and thick fiberglass layers with the foam in between them. There's never been a problem with a Bayliner hull that I know of, but this is new territory.

All I know about the gyros is the several magazine articles I've read over the last couple years and what I've seen on the web sites.

What I do know is that the units are coming down in size and price enough to warrant some serious due dilligance.

What I do know is that if it works as advertised it would be a very nice addition to my boat.

So, the quest for information is on. First step is to contact the manufacturer and ask them which unit they recommend for my boat and for their anticipated roll data for my boat.

After that we start looking at the other installation aspects, but first steps first.
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Old 03-28-2015, 03:21 AM   #26
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Navigator had a gyro on MV Kekada, and if his build blog is still accessible there will likely be some details of it. It was not a Seakeeper though, but rather a cheaper brand. It may not have been as good as Seakeeper. But, Don indicated that the gyro gave his wife seasickness due to a 'snap-back' characteristic and that he would never have another one. Unfortunately he did not get the opportunity to test as thoroughly as he wanted due to the explosion and loss of the vessel.

As we know, active fins have accelerometers in their control boxes and the fins are continuously adjusting. They are variable rate devices that can adjust the amount of righting moment applied. Navigator's gyro probably did not have that capability, and I have no idea whether the Seakeeper does either. But it seems to me to be important for attenuating roll in a comfortable manner. I hope Kevin's research can shed some light on this. Next boat show I should try and get more info from them as well....
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Old 03-28-2015, 10:35 AM   #27
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Wait a minute!!! You've got me already installing the thing
Come on, take one for the team
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Old 03-28-2015, 11:21 AM   #28
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Looks like seakeeper has hydraulic cylinders that can rotate the gyro assembly relative to roll axis. So it is more than a simple gyro. This rotation presumably can be controlled actively in manner similar to fin stabilizers.

Regarding the forces on boat structure, I do see the numbers posted for torque. But I really think the actual forces in normal ops will be substantially less than these posted maximums. So yep you need to design for the max, but in actual use I think getting into a hull ripping fatigue situation is not that likely. Just going by gut feel here. Damping an oscillation at natural frequency usually involves small to moderate forces. The flopper stopper analogy is appropriate. I would try to span across as many structural elements though, as much as practical.
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Old 03-28-2015, 11:28 AM   #29
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New Seakeeper gyro

That Seakeeper gyro unit is a really interesting option, for sure. Do you have info on the power draws after "the ball" is up to speed? Maybe the unit can run on the inverter power after a point.

I'm no expert, that's for sure, but I do wonder about the placement of he unit in the lazarette. Intuitively I would think placement would be best amidships. Perhaps a friendly phone call to an independent naval architect might answer that question.


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Old 03-28-2015, 01:07 PM   #30
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Too late Kevin, since that anchor episode you have been coronated the official Trawler Forum beta tester. Shut up and write the check already
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Old 03-28-2015, 01:49 PM   #31
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Too late Kevin, since that anchor episode you have been coronated the official Trawler Forum beta tester. Shut up and write the check already
I live pretty close. If everybody chips in for diesel and lost wages I'd be more than happy to go up there and slap him around a little.
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Old 03-28-2015, 02:03 PM   #32
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Too late Kevin, since that anchor episode you have been coronated the official Trawler Forum beta tester. Shut up and write the check already

Yeah, take one for the team.

And then we'll tell you what you did wrong; after the fact
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Old 03-30-2015, 10:36 PM   #33
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Just like any major addition to your boat you better get the design signed off by the vessel designer, engineer or builder for obvious and not obvious reasons.

Even though our fin stabilization protrudes and shaves .5 knot off our hull speed I wouldn't go for a gyro if it wasn't engineer approved as the centrifugal force on the hull is huge plus you have to run your gen the whole time you want the stabilization plus the warm up and cool down times are pretty lengthy.

Also check your insurance coverage if you add one without engineering approval and a catastrophic hull failure occurs.
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Old 03-30-2015, 11:00 PM   #34
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Just like any major addition to your boat you better get the design signed off by the vessel designer, engineer or builder for obvious and not obvious reasons.
In many cases they are dead, never existed, out of business, unwilling to return calls or all all of the above.

Truth is you don't really need to contact any of those people to do a simple stabilizer install. Nice if you can but hardly mandatory. Or you can contract an outside "expert" if feel the need.

The companies that build the systems, along with their insurance companies, have a vested interest in seeing that their systems are installed correctly and safely. So they tend to be very helpful and knowledgable about how to go about it the right way.
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Old 03-30-2015, 11:10 PM   #35
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http://www.seakeeper.com/uploads/doc...08.27.2014.PDF


http://www.seakeeper.com/faq
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Old 03-31-2015, 09:22 AM   #36
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Don't people do that in general? Plus the extra time you take to let the system warm up pays off once you anchor up in that anchorage at the end of the day that no one else can use but you because of the surge or swell that would have them rolling all night but your the one enjoying a comfortable meal and nights rest.

Once you have at rest sabilization it can open up a whole new world of anchorages.
I really do hate to ask this question, but, will this require a different anchor?
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Old 04-01-2015, 08:15 AM   #37
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Seakeeper answers

Hello All,
My name is Brook Stevens and I am a Seakeeper representative. I am based in Maryland. I'm more than happy to answer any questions in regards to Seakeeper. I've been with the company since 2009 so I can provide many facts as there are a lot of misconceptions about gyroscopic stabilizers. I will make the general statement that yes, we have shipped well over 2000 systems since March of 2008. We are set and forecast shipping 1000 units in 2015 and are certainly on pace. We have stabilized over 130 different brands of boats. If you have any technical questions or if I can assist in any way please let me know. I can be reached at 410-326-1590 x 137 Thank you kindly.
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Old 04-01-2015, 08:55 AM   #38
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Hello All,
My name is Brook Stevens and I am a Seakeeper representative. I am based in Maryland. I'm more than happy to answer any questions in regards to Seakeeper. I've been with the company since 2009 so I can provide many facts as there are a lot of misconceptions about gyroscopic stabilizers. I will make the general statement that yes, we have shipped well over 2000 systems since March of 2008. We are set and forecast shipping 1000 units in 2015 and are certainly on pace. We have stabilized over 130 different brands of boats. If you have any technical questions or if I can assist in any way please let me know. I can be reached at 410-326-1590 x 137 Thank you kindly.
Welcome to the forum, Brook. As there are plenty of questions on this thread, why not start by answering the questions that have been posed this far? I warn you, this crowd is pretty savvy, and specifics are important....

I, for one, look forward to your info.
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Old 04-01-2015, 09:13 AM   #39
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Seakeeper manufactures 5 models.
The Seakeeper 5 - configured for vessels up to 20 tons of displacement
The Seakeeper 9 - configured for vessels up to 35 tons of displacement
The Seakeeper 16 - configured for vessels up to 70 tons of displacement
The Seakeeper 26 - configured for vessels up to 100 tons of displacement
The Seakeeper 35 - configured for vessels up to 140 tons of displacement

When we size, we strive to achieve 70-90% roll reductions.

The units are bonded or bolted to the hull structure or stringers of the vessel. They do not need to be on centerline and multiple units can be installed as well. We don't want to go too far forward of amidships on planing hulls in terms of location. In terms of power draw, our smallest system, the Seakeeper 5 only requires 2KW to spool up and it will operate typically at about half that (5-7 amps) and it will never exceed 2KW. Our 9, 16 and 26 will never exceed 3KW and our 35 will never exceed 5KW. We are actually going to be offering a DC version of the Seakeeper 5 soon and we've had certain clients set their hulls up to run off inverter... rare, but it has been done. Seakeeper has stabilized hulls from 35 feet to 210 feet in length. We've installed units on older wooden boats built in the 30s to the most modern hulls designed to date. We have a global network of partners trained to install and service our product. We have demo boats set up all around the world as well if anyone is interested. Feeling is believing as we say.

Please feel free to visit our website or contact me for additional information.
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Old 04-01-2015, 10:00 AM   #40
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Hi Brook:

Welcome to the forum and welcome your input.

Here is a specific, technical question for you:

I suspect that older gyro stabilizers were passive. The gyro spun up and any roll was passively resisted by induced the gyro torque as the boat rolled. That scheme was reactive and didn't anticipate roll and also was limited in the torque that it could produce.

The Seakeeper system looks like it has hydraulic actuators that can move the spinning gyro and generate force independently of the ship's motion. That means it can anticipate roll and create more stabilizing torque than a passive system.

Do I have it right?

Also do you have any test data on a full displacement trawler like the Krogen but underway, not at anchor like the current test data on your website.

David
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