The perils of Stabilizers

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Ski

I don't care for fins sticking out either but having never been on a gyro boat it seems appealing. We are contemplating a new boat and the fins have kept two deals away. Hard to find boats with gyros and certainly don't want to build one again.
 
Bigsfish said:
Ski

I don't care for fins sticking out either but having never been on a gyro boat it seems appealing. We are contemplating a new boat and the fins have kept two deals away. Hard to find boats with gyros and certainly don't want to build one again.
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Fins have a couple of advantages though. One is as speeds increase and the other is they don't require spooling up which can be a 45 minute process. The current trend in larger boats is to have both fins and gyros.
 
I can attest to the tough conditions on the Trent this year. We came through the same area two days later with our 35 foot trawler and it's a tough slog in some of the narrow spots. We have to go the other way next week and I'm hoping things will have slacked off a bit. That said, we're a bit surprised at where she went down. The section near the Hamlet swing bridge didn't seem that bad.
 
Here are some pics of the KK42 on the hard. It is in Orillia. 1 good stabilizer, one hole with patch used to refloat it and all the interior being torn out to deal with the water damage. Such a shame but salvageable no the less.
 

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Tough to say much from the photos. The only clue seems to be the radius of the bolt circle on the patch. Presumably everything inside the bolt circle is damaged
 
Thanks for the pictures. There looks like a scratch/tear on the hull forward of the patch. I wonder if the hull was the first point of contact?
 
Aren't the Krogen owners talking up a storm over this? There must me more first hand info available.
 
Does anyone know of other cases of the fins breaking off the hull and sinking the boat?
 
Larry M said:
Thanks for the pictures. There looks like a scratch/tear on the hull forward of the patch. I wonder if the hull was the first point of contact?
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That scratch is actually aft of the hole Larry, likely where the stabilizer hit after contacting the rocks.
 
Late to the show here. Very sad to see. Very sad indeed.

My 1988 Krogen 54 has a cored hull (Airtex - PVC) and Wesmar fin stabilizers. From the soundings I took on the hull at haulout it sounds very much like the area around the installation is solid cored. I don't have records when the installation was done.

Richard
 
hmason said:
These stabilizers use compressed air not hydraulic fluid. Need 4 - 6 fins. I know someone that had them installed and is pleased. 4 fins, is that double trouble? Interesting though.
Gyro-Gale Stabilizers - Gyro-Gale Stabilizers
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Interesting, but I am always suspicious of products that make silly statements on their home pages. Makes you wonder.

"Additionally, Gyro-Gale Stabilizers have a much shorter start up time. Where other stabilizer systems require a minimum of 30-45 MINUTES to start up, Gyro-Gale Stabilizers start up in as much as 15 SECONDS."

I guess by "other stabilizer systems" they mean gyros. Their main rap against hydraulics is that air is clean and oil is dirty. I guess. The tab driven fin is pretty cool though.
 
Britannia said:
I took on the hull at haulout it sounds very much like the area around the installation is solid cored. I don't have records when the installation was done.

Richard
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I wouldn't be surprised if it were solid laminate.
 
Britannia said:
Late to the show here. Very sad to see. Very sad indeed.

My 1988 Krogen 54 has a cored hull (Airtex - PVC) and Wesmar fin stabilizers. From the soundings I took on the hull at haulout it sounds very much like the area around the installation is solid cored. I don't have records when the installation was done.

Richard
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What does "solid cored" mean? Is it solid, or cored?
 
If you put a stabilizer fin on a cored boat, you want to grind out the coring from the inside and build it up solid. And you also need to add structure from that solid pad to nearby ribs and stringers. Without that added structure it will be weak at the edges of the solid region where it meets the cored area.

Would have to see the failure area from both inside and out to get a feel for what happened.
 
Britannia said:
I meant solid - not sure why I wrote that.
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Thanks. Makes sense now.

I do wonder if a boat had a cored hull, how you would install stabilizers? I would think you would need to route out the coring in at least the area where there will be thru bolting to address compression issues. Then do lots of reinforcing layers back to structural members to take all the torsional loads. Such a buildup is usually required on a solid hull, and I would think a lot more would be needed on a cored hull to create equivalent strength.

Alternately I suppose you could remove the inner hull layer in the entire area around the stabilizer, remove the coring, and build up with solid glass, thereby creating a solid region in an otherwise cored hull.

It will be really interesting to hear how this particular boat failed. My guess would be that it's related to the install, perhaps compounded by a cored hull if this particular boat has one. I doubt there is anything Kadey or Naiad specific, just the usual installation risks in engineering and workmanship.
 
twistedtree said:
Thanks. Makes sense now.

I do wonder if a boat had a cored hull, how you would install stabilizers? I would think you would need to route out the coring in at least the area where there will be thru bolting to address compression issues. Then do lots of reinforcing layers back to structural members to take all the torsional loads. Such a buildup is usually required on a solid hull, and I would think a lot more would be needed on a cored hull to create equivalent strength.

Alternately I suppose you could remove the inner hull layer in the entire area around the stabilizer, remove the coring, and build up with solid glass, thereby creating a solid region in an otherwise cored hull.

It will be really interesting to hear how this particular boat failed. My guess would be that it's related to the install, perhaps compounded by a cored hull if this particular boat has one. I doubt there is anything Kadey or Naiad specific, just the usual installation risks in engineering and workmanship.
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I've seen some cases where builders used different core materials locally, like substituting plywood for balsa in through hull locations. So it's not always a binary core/no core decision.

Interesting thread, but I wonder if the stabilizer issue is being overblown. Whatever the boat hit was likely solid and immovable - a large rock or a ledge. I wouldn't assume that the boat would have survived had it been a few feet over and nailed the hull. Some risks can't be avoided even with perfect engineering.
 
Jeff F said:
I've seen some cases where builders used different core materials locally, like substituting plywood for balsa in through hull locations. So it's not always a binary core/no core decision.

Interesting thread, but I wonder if the stabilizer issue is being overblown. Whatever the boat hit was likely solid and immovable - a large rock or a ledge. I wouldn't assume that the boat would have survived had it been a few feet over and nailed the hull. Some risks can't be avoided even with perfect engineering.
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Agreed, but solid glass sections in a cored hull requires advance knowledge of what's going to be installed where. I'm wondering about retrofit where no such provision was built into the hull. ski's and my posts passed in the etherweb saying pretty much the same thing.

And I agree one can't say the boat sank because of the stabilizer, and wouldn't have otherwise. But the stabilizer did apparently come off/apart, and I'd be real interested to understand the failure.
 
This should be obvious. In addition to the overall weight and power requirements for a gyro to stabilize a reasonably sized boat, you also need to have the correct hull structure to handle the stabilizing loads placed on the hull by the gyro.

Any upset of the boat is going to result is a torque load on the hull counter to the direction of upset. The hull has to be able to handle it otherwise you'll end up ripping the gyro out of the hull. Retrofitting a gyro into a hull not originally designed for it can require extensive work. Fins may be an easier solution on some boats.
 
We knocked the fiberglass of a fin off one of our Naiads on our old Hatteras. Left the stainless inner frame behind. Didn't notice it was gone until a haul out a few months later and we operated them whenever the boat was underway. I had to think back a bit as there were maybe a couple of incidents where it could have happened. You'd have to hit something really hard to do much damage. I wouldn't hesitate to use fin stabilization on any future cruiser.
 
Seakeeper Refit

Did not want to respond until we had finished the retrofit of a Seakeeper 6 into our 2003 Defever 45 RPH. As several of you had commented, the idea of something sticking out from the hull of your boat is worrisome. We are coming new (last year) to the trawler side of the house from sailing. We spent nine years (extended summers) in the Mediterranean before selling the sailboat. We have experience in snotty beam seas, but 3 ton keel and big main go a long way toward stabilizing and smoothing the rolling moment.
When we bought our trawler, it was a Great Lakes boat without stabilizers. We researched all the various manufacturers of stabilizers, be they Naiad, Abt-TRAC, RotorSwing, Side-power, and Seakeeper. We even took a test ride in the Seakeeper test boat at the Annapolis Boat show. When we priced all of them out, Seakeeper came out more expensive, but not a lot more. The RotorSwing and Side-power were more expensive due, in part, to the per diem cost for the installers.

The biggest deciding factor was no hull protrusions. While we had already contracted for the install, this incident posted herein just sealed the deal.

We just finished the install and completed our sea trial and return to winter port for storage (we're in Michigan so the boat goes indoors). Our first impression is impressive, but the seas were on 2-3 feet so it wasn't hard to flatten that out. Our Seakeeper app showed us with a 86% roll reduction. Soon I'll write up the install with pix, etc.
Regards
Gary
 
Gary, how are you powering the Seakeeper? I think they are a great product, especially when trolling or in a rough anchorage, but the cost of running a genset all the time just for the stabilizer seemed to offset the cost of maybe having a rare incident of losing a fin.
 
George,
The Seakeeper requires both 12 vdc for the controller and touchscreen' and 115/230 vac for the water pump and spinner motor. The larger units require at least 230 vac. We have a 8 kW generator that uses less than 1/2 gal per hour of fuel. Yes, you must run the gen set while using the stabilizer. My understanding is that you must also supply power to a hydraulic pump, etc for fins, though maybe not using as much additional fuel. Noise is not a factor as the gen set is running. Fortunately for us, the gen you has a sound enclosure, the engine room has good sound insulation and we have a carpet with pad on top of that. The good news is all of my batteries are fully charged when I get into the anchorage.:thumb:
Gary
 
GGroves said:
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When we priced all of them out, Seakeeper came out more expensive, but not a lot more. The RotorSwing and Side-power were more expensive due, in part, to the per diem cost for the installers.
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Regards
Gary
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Gary
You mentioned per diem cost. I am curious, could you share the per diems rates for the various brands?
 
twistedtree said:
There are so many factors at play. It would be really educational to learn exactly what failed and how.

But before we get too far down the path of "stabilizers are bad", consider thruhulls for toilets, air conditioners, water makers, etc. They fail all the time for a wide range of reasons, and sink boats. Some aren't installed correctly, or degrade over time, or are of the wrong material, or have bad clamps, or have bad hoses..... Yes we still keep them all so we can enjoy those conveniences.

Everything on a boat is managed risk. There will always be failures, and just because there are isn't a reason not to take on a calculated and managed risk.
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:thumb: very well stated
 
Unfortunately, the quotes came in as product price plus labor and in some case plus per diem. No real specifics. The RotorSwing (from the Netherlands) estimated 20 hours install labor, plus travel costs. I assume, since they are a Dutch company, they would be coming from the Netherlands. They did indicate that they would rely on a local yard for assistance, so it would be hard to really put their total costs together. Stabilized Marine did quote a Naiad at a base $47k including labor, plus any additional time and labor costs to move, replace, modify the boat to fit in the actuators.
Gary
 
Thanks Gary. That Naiad price seems about right.

I asked because one of the brands here quoted $175/hr for their senior guy and $125/hr for junior staff. To me those rates sounded quite high.
 
I think when we see more details, it will reveal the base of the installation punched thru the hull. In other words, the area they made that was solid was not supported enough at the edges.
Poor installation. Period.

Rolling is such an insidious nuisance, that the cure is not to get rid of stabilizers.

More importantly, it does make me think of what actions I would take if presented with such a hole in the hull.
Looking at these pictures, the hole would have been virtually impossible to reach, it it would be under the second cabin floor, outside the fresh water tanks.
 
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