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Old 03-27-2015, 02:38 AM   #1
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New Seakeeper gyro

I just read that Seakeeper came out with a new gyro stabilizer for smaller boats.

The Seakeeper 5 is for boats up to 50' and 20 tons.

It uses 2 kw of 110 volt power, is 30"x30"x25" and weighs 720 lbs

MSRP is $29k

With the smaller size and lower cost this might just be the ticket.

I've thought about stabilization quite a bit for my boat. I'm going to go look but I think I can jockey some stuff around and find room.

At a minimum it's something I think is worth seriously considering. I really like that it works without forward motion. That's great for rolly anchorages and drift fishing,
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Old 03-27-2015, 07:00 AM   #2
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I just read that Seakeeper came out with a new gyro stabilizer for smaller boats.

The Seakeeper 5 is for boats up to 50' and 20 tons.

It uses 2 kw of 110 volt power, is 30"x30"x25" and weighs 720 lbs

MSRP is $29k

With the smaller size and lower cost this might just be the ticket.

I've thought about stabilization quite a bit for my boat. I'm going to go look but I think I can jockey some stuff around and find room.

At a minimum it's something I think is worth seriously considering. I really like that it works without forward motion. That's great for rolly anchorages and drift fishing,
.
That's about the weight of 4 people; impressive! A little Honda suitcase could probably run it at 2kw max draw.

Good pricing too at under 30k......

The big advantage I see is no fins to get damaged in shallow canals or in harbours, plus no drag at higher speeds.
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Old 03-27-2015, 07:39 AM   #3
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Originally Posted by Rustybarge View Post
That's about the weight of 4 people; impressive! A little Honda suitcase could probably run it at 2kw max draw.

Good pricing too at under 30k......

The big advantage I see is no fins to get damaged in shallow canals or in harbours, plus no drag at higher speeds.
The big advantage is it works at anchor or even at the dock.

Once you've had at anchor stabilization and just like after the first time you've had a boat with underway stabilizers, you'll never want to be without it again.
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Old 03-27-2015, 08:14 AM   #4
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Actually they have been talking of this smaller version for the last two years. I agree with all the above advantages.

Now, some big disadvantages, for me at least:

Must run the gen all the time to run the seakeeper,
Cost, $30k means $40k and that's still 4 times what I could afford or wanted to pay,

And the MAIN disadvantage, is in a retrofit.

No matter how strong they made the stringers in your engine room, no way was anything in there ever designed to take the torque loads the seakeeper will make.

I do like it for a new build, if I intended to run the gen most of the time.
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Old 03-27-2015, 08:41 AM   #5
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Actually they have been talking of this smaller version for the last two years. I agree with all the above advantages.

Now, some big disadvantages, for me at least:

Must run the gen all the time to run the seakeeper,
Cost, $30k means $40k and that's still 4 times what I could afford or wanted to pay,

And the MAIN disadvantage, is in a retrofit.

No matter how strong they made the stringers in your engine room, no way was anything in there ever designed to take the torque loads the seakeeper will make.

I do like it for a new build, if I intended to run the gen most of the time.
Hi Richard,

Hope all's going well for you in Waterford. Did you get the info about the low bridge on the Shannon; it's a good time to start cruising now the spring weather
Has arrived.

I was just thinking that the torque para vanes exert on the hull doesn't seem to stress it too much, would a Seakeeper exert much more on the stringers?
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Old 03-27-2015, 09:19 AM   #6
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Old 03-27-2015, 09:40 AM   #7
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Another plus is that in calm running or quiet anchorages, it and gennie can be turned off. I find that I only rarely desire stabilization, but when I want it it would REALLY BE NICE!!

My gut feel is that the forces on the stringers would not be that high, but have nothing beyond gut feel to back that up. Rolling is the boat moving at it's natural frequency, and in any such system the forces needed to begin or end that motion generally are not that large. Even then, where it is located needs to be structurally beefy for the weight alone.

I wonder what the power requirements vs. roll intensity look like. Does it take 2kW to spin in idle conditions? Or just when it working against a roll?

Maybe a DC version could be an idea.
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Old 03-27-2015, 10:07 AM   #8
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Hull loads are high with the Seakeaper- 13,000 NM or 10,000 ft lbs according to their literature, but no different than paravanes or hydraulic vanes. It takes so much torque to stop roll no matter how it is generated.

The real problem is that they are concentrated with the Seakeeper. With a 30" width that means that the 10,000 ft lbs produces about 8,000 lbs of force at the outboard edge of the Seakeeper housing. This will almost certainly require a fabricated aluminum frame to distribute the load transversely.

Once that force is transferred say 5' outboard, it gets down to about 2,000 lbs which sounds a bit more manageable. If it were mounted next to a structural bulkhead, the aluminum frame could transfer the load to the bulkhead/hull/stringer system. Otherwise I suspect it would take a good bit of glass work to layup cross members to transfer the load down to the hull and stringers.

It is all doable, and probably no worse than reinforcing a hull to take paravane or hydraulic vane forces. But since these are applied way out near the maximum beam, they are lower, although a paravane system has to deal with wave and potential impact and sea weed generated forces.

The real question is how well does it work? Any feedback on the bigger models? Seakeeper provides test data on a Krogen and Grand Banks, but both tests are done at anchor facing beam seas. It does cut roll in half which is better than almost anything else can do at anchor. But what is the performance like underway.

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Old 03-27-2015, 10:33 AM   #9
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A good friend of mine is the West Coast rep for SeaKeeper. He's been talking to us about installing one on our boat, and it does look enticing.

It can be installed centerline or off centerline, and once up and operating, it fairly low power draw. I was impressed with the model at the Seattle Boat show.

The ideal install location for us would be where our genset currently resides. Push comes to shove, we could make it work, but at this point I'm not totally committed.

For sure, this would be a better install during a build or total refit.
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Old 03-27-2015, 10:58 AM   #10
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A good friend of mine is the West Coast rep for SeaKeeper. He's been talking to us about installing one on our boat, and it does look enticing.

It can be installed centerline or off centerline, and once up and operating, it fairly low power draw. I was impressed with the model at the Seattle Boat show.

The ideal install location for us would be where our genset currently resides. Push comes to shove, we could make it work, but at this point I'm not totally committed.

For sure, this would be a better install during a build or total refit.
There's a guy on the mbm forum who retro fitted the bigger Seakeeper 9 to his boat, and with all the extra costs of the fit out etc etc it ended up being twice the original price of the gyro unit.

I think each different application needs a special frame and pick up points.
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Old 03-27-2015, 11:00 AM   #11
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As mentioned, hull integrity and redesign on a retrofit would prove the challenge. Of the several retrofits I have read about all were on solid FRP hulls. My guess is an older composite hull would prove to be an expensive and technically challenging endeavor, well above the purchase price of about $30K.

Active at rest stabilizers are an option too, Twistedtree has these as do several others. For vessels running gensets most of the time, either option seems attractive, with space limitations and no genset requirement - when cruising - favoring the fins on slower vessels.

P&MY magazine has tested many vessels with Seakeepers during the past few years, all reports as I recall were positive. The latest I read with interest was on my favorite boat of the moment, an MJM 50. But they do require an operating genset. Ski, a low voltage motor and wiring would be larger in comparison to 110/220V wouldn't it?

RickB started a good thread about a year ago on this subject. If I were to consider a retrofit, my first consult would be with RickB.
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Old 03-27-2015, 11:27 AM   #12
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I'd love to have one of these, even at that price, but I don't kid myself about the forces involved here. At over 7000 lbs. ft. at 30 or so inch spread, eventually (if not imediately), such forces would debone my boat like a chef like a overdone fish. Unless I could spread those forces out to the cap-rail (full beam), I couldn't use it.
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Old 03-27-2015, 12:07 PM   #13
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As a guy thats been considering stabilization for some time here are some issues I've identified with either fin or gyro stabilization.

Fins

The actual fins for our boat would be placed behind the forward head vanity and under the berth in the "bunk" stateroom. This would require dis assembly of these internal areas, and significant hull build up in these areas. This is an extremely labor intensive process.

The hydraulic pump would be located on one of the transmissions, and a 5 gallon hydraulic tank would be located in the engine space as well.

I was quoted $27K from Wesmar for the basic gyro and fins of a proper size to provide underway syabilization. For the advanced gyro and larger fins to provide at rest stabilization the parts cost rose to $39K. Wesmar has done several 4788 installations so they have allot of the engineering done for my boat.

As far as installation fins require significant specialized labor skills that I do not possess. The fiberglass layup at minimum would have to be outsourced. I could do the mechanical and electrical work myself. I'm estimating it would take a "season" to do the install by the time I do everything and get it all cleaned up.

Advantages of fins are that they do not require the generator to operate.

Disadvantages are that the specialized labor for the fiberglass work is not readily available in Seward Alaska.

Since I sometimes run my boat at a higher than displacement speed cruise, my performance would be impacted. The simple fact is that fins will add drag and at a higher power setting the drag needs to be accounted for.

SEAKEEPER GYRO

The Gyro unit would be located in the lazarette. As Pete indicated the best place would be where my generator currently is. On my boat the two main stringers run the length of the boat and would be a perfect place to bolt the gyro unit to.

Moving my generator and re-arranging my lazarette is something I could easily accomplish myself with my existing skill set.

Bolting in the gyro is also something I could accomplish myself. I would consult Seakeeper and probably have a set of brackets to fit my stringers made up. They also have the potential of bonding the unit and or the brackets to the stringers to help dissipate the loads.

I'm estimating that the lazarette re-arrangement would take me a week to do. Installing the gyro might take me another week but I think it would go much quicker than that if I had mounting hardware pre-fabricated.

Gyro advantages are that the thing works at anchor and while drift fishing.
Running the generator is a disadvantage. This disadvantage is mitigated by the fact that I have a brand new Northern Lights generator that is very quiet and designed for continuous operation.

Weight is a disadvantage of the gyro, but we need to remember that the fins are not without weight themselves. The weight of the fins is a few hundred pounds total but the weight is distributed better with the fins than the gyro.

This is interesting enough that I'm going to start studying the feasibility of fitting the gyro into my lazarette.


There has been allot of discussion in this thread about loads being applied to the boat. We need to keep in mind that these are not shock loads, they are loads that are applied to counteract wave action loads.

With fins for example, in an installation on my boat they have been successful with a 2'X2' backer being glassed into the hull beneath each fin with only one edge having a connection to an existing stringer, and that stringer not being one of the two "main" stringers on the boat.

The gyro the unit would be attached to the two main stringers and the loads would be applied to those stringers. Those stringers run the length of the boat and by nature would dissipate the loads into the hull areas which are attached the entire length.

The only worry I have with the gyro is to spread the loads applied to the stringers over as large an area as possible. If for example I had a mount (think engine mount here) fabricated then the force would all be applied to the mount creating large compression loads in a small area. If I was able to use a plate for example and spread that load over a 3' area of stringer then the loads per square inch would be much smaller.
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Old 03-27-2015, 12:42 PM   #14
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Kevin

Who would you use to perform the required re-design of the hull and field testing to insure no delamination or saturation from new in the composite hull? Neither of these are negatives, just preparatory pre-install tasks IMHO.
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Old 03-27-2015, 12:56 PM   #15
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Kevin

Who would you use to perform the required re-design of the hull and field testing to insure no delamination or saturation from new in the composite hull? Neither of these are negatives, just preparatory pre-install tasks IMHO.
To be honest there is little chance of my engaging a naval architect for this. If I have to do that the project will stall and never move forward.

I think this is just like the 2' backer plates that have been successfully used for fin installations in my hull. I'd bet that no naval architect was engaged, and no in depth hull studies were conducted.

I don't want to call it over engineering because its not, but at some point a decision has to be made, just like any other modification to a boat.

I would bet that the boats that seakeeper gyro's have been retrofitted to did not have their hulls re-designed either, but I'll of course check. I'd be foolish not to, but again if a hull re-design is required then the project stops right here right now.
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Old 03-27-2015, 12:59 PM   #16
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These hi output alternators would run the gyros: Alternators: Mastervolt Alternator 24/150 Incl 3-Stage Charge Regulator (M48524150)

100amps output at 1000 engine revs!
150 amps at 1900 revs.
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Old 03-27-2015, 01:01 PM   #17
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I see the new Seakeeper is rated for boats up to 20T. What's the displacement of your Bayliner? I would have guessed a good bit more than that.

Regardless, if you do the install, please post the whole process, especially the results. I think we would all be real interested. I simply don't believe magazine reviews. They are in the business of promoting the industry, and are all happy thoughts, all the time. Some are worse than others, but make no mistake what their job is.
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Old 03-27-2015, 01:33 PM   #18
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Regardless, if you do the install, please post the whole process, especially the results. .
Peter, you did a nice job on reporting your thruster install. A very good template for reporting on a worthwhile project IMHO.
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Old 03-27-2015, 01:51 PM   #19
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Kevin,

David did a nice job of explaining what I was trying to say.

I would think that you should be able to get some information or help from Bayliner. They know who they designed and built your boat. I would think, they could tell you exactly what type of frame was needed and where.
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Old 03-27-2015, 04:12 PM   #20
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Kevin: I think you've got the right boat to do this with and if I had a 4788 I'd be seriously thinking about it too, but I'm not sure about the lazarette location in an uneven sea. Wouldn't the stabilization forces at one end of the boat tend to somewhat warp into directional forces at the other, swinging the bow port or starboard?
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