Report on Active Fin Stabilizers

You may recall late last year I decided to install a set of Naiad 252 fins with Datum controller on my GB46. I posted a thread about it, and some photos of the works being carried out, and there were some helpful suggestions from TF members which helped shape some of the install.

I have had them operating for a while now, and thought I would post an "independent as possible" review for those who are interested or even considering the same job.

First up, roll reduction. I bought a 1 litre bottle of water from the shop, tall and thin with a narrow base. With a small beam sea on Moreton Bay near Brisbane, the stabilizers off and steering from the flybridge, and the bottle placed on a flat surface near the wheel, the bottle would topple over almost as soon as you take your hand off it. Turn the stabilizers on, and the bottle never toppled, even during tight turns. An app on the Naiad guy's phone measured the roll at 6 degrees with stabilizers off, and about 1 degree with them on. The roll reduction has made the boat measurably more pleasant to travel on, and for some (false) reason it also makes me feel more confident while underway when the seas are up.

Speed. In calm conditions, with the stabilizers on or off, I reckon the boat is about three quarters of a knot slower. She used to do 15 Knots at 60% load on the engines, now in similar tide conditions she does 14+ at 60% load. But it is different when the seas are up - with the stabilizers on the boat travels faster than with them off plus the autopilot isn't constantly making course corrections (less frequent corrections, and when it does correct the amount of the correction is reduced). I am coming to the view that when the seas are up and the stabilizers are on, we are actually able to travel a bit faster than we used to be able to (as weird as that sounds).

Noise. Underway there is a slight sound in those cabins which sit above the actuators. Not enough to concern me. However when at rest in the quiet of the night, the stabilizers do make a bit of a racket as they flop around with the currents. I have asked Naiad to install a device on each actuator to hold the fins at centre when powered off, which they can easily do (had I known of this problem, I would have asked them to install these from the outset).

Ease of use. Very simple. The new Datum controller is pretty intuitive, and so far have just used it in the 'Adaptive' (ie automatic) setting.

Overall I am very pleased. The addition of stabilizers has made the boat much more 'approachable' and user friendly. I think it will make my annual Bluewater trips to the Whitsundays and to Sydney much more pleasant and less tiring.

And I cannot understand why, if a person is buying a new trawler and paying out a very substantial sum, they don't always agree to the comparatively small incremental cost of stabilizers and have them installed from the outset. Makes a huge difference!

H.

Thanks for the update Hamish. I'm surprised about the possible gain in speed in rough water, but when you think about the overall forces, it does make sense that the boat is more efficient when properly aligned in the water, and the AP has less error.

I'm certainly sold on any type of stabilizer system.

Do they provide any roll reduction at anchor with an unfriendly swell?

The ones I have don't help at anchor. They are available, but they cost more and would have even more drag plus you have to run the genset all the time.

H.

BrisHamish said:

Y
Noise. Underway there is a slight sound in those cabins which sit above the actuators. Not enough to concern me. However when at rest in the quiet of the night, the stabilizers do make a bit of a racket as they flop around with the currents. I have asked Naiad to install a device on each actuator to hold the fins at centre when powered off, which they can easily do (had I known of this problem, I would have asked them to install these from the outset).

.....

And I cannot understand why, if a person is buying a new trawler and paying out a very substantial sum, they don't always agree to the comparatively small incremental cost of stabilizers and have them installed from the outset. Makes a huge difference!

H.

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Glad you are really happy with them - not that there was ever going to be any doubt. Now I've had them I would only buy a boat with them or have them fitted immediately after purchase.

But I would also look closely at Seakeeper as an alternative. Probably not as good for roll reduction under way, but at anchor it would be great. Frankly, I think the Naiad's reduce the roll a lot more than is needed for comfort, so the gyro might be fine.

Mind you, the Naiad's could not really cope for me one day last year in Hervey Bay. Shallow water, 25kn of wind against an outgoing tide. I got a bit beat up....

My Multisea II controller has a 'centre' button that you can use at any time. When off, they are centred and held in place (hydraulic lock). I thought that was standard? You would have the manual locking pins, but it would be quite inconvenient to use them every time you anchor up.

On larger boats now, it's becoming quite popular to have both Naiad and Seakeeper.

To me one big advantage to the ABT stabilizers are their automatic locking pins. They are spring loaded, and release when you shut down the hydraulics, locking the fins in their center position. They can also be locked from the control panel, and lock as a safety measure any time you are reversing.

And they have stabilization at rest, so work in rolly anchorages.

BandB said:

On larger boats now, it's becoming quite popular to have both Naiad and Seakeeper.

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Interesting. I have not heard that.

Since NAIADs have at anchor stabilization as an option, what's the rational?

Redundancy?

The Seakeepers are quieter at anchor?

When we first bought a boat with stabilizers we couldn't believe how much stuff was NOT bolted down of the ship .
The ride was fantastic try a simple test in calm weather a turn at 30 degrees with them on and then a turn off you will notice what an improvement they make .
Our naiads auto self center below a set speed and also can be centered by user. Good when your coming into dock

Surf the trough
Waves on your side 45 deg were you speed up to increase the performance of the fins and you ride the trough between waves crests

Good to get the old blood a flowing
You will be happy with the upgrade

Capt.Bill11 said:

Interesting. I have not heard that.

Since NAIADs have at anchor stabilization as an option, what's the rational?

Redundancy?

The Seakeepers are quieter at anchor?

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Redundancy and options. Even using both under some conditions. I think in calm seas they may not use the Seakeepers but then turn them on for worse conditions.

I know Westport delivered one or more boats that way and Heesen has. A couple of others I can't remembeer. Now, I think it might also be because Naiad was standard and they decided to add the Seakeepers. Wanted to let the Seakeepers prove themselves before eliminating the Naiads, perhaps too.

BandB said:

On larger boats now, it's becoming quite popular to have both Naiad and Seakeeper.

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Seems to me a decent catamaran would solve those issues

We don't have either and after near a year cruising around the bay in mostly ideal conditions (as we have no time constraints) haven't considered them.

For those that have them, would you need them if time wasn't an issue and you could pick your weather?

Simi 60 said:

Seems to me a decent catamaran would solve those issues

We don't have either and after near a year cruising around the bay in mostly ideal conditions (as we have no time constraints) haven't considered them.

For those that have them, would you need them if time wasn't an issue and you could pick your weather?

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We don't want to cruise only in ideal weather. One, that leads to not seeing as much as we desire. Second, we enjoy some variety in conditions. We don't want to cruise when it's dangerous or horribly uncomfortable, but otherwise we do.

To us, time is an issue in that you only have so much in your life and more places you want to see than you ever can. We don't want to just cruise around the bay. Nothing wrong with doing that but "we have places to go, things to see." In your search for ideal conditions, we'd never cruise the Caribbean. We'd have far fewer trips to the Bahamas.

I realize we're not the norm here, but I'd feel a great restriction following the perfect conditions philosophy.

Simi 60 said:

Seems to me a decent catamaran would solve those issues

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What is your definition of a decent catamaran? Give me an example of one that currently is built.

Simi 60 said:

For those that have them, would you need them if time wasn't an issue and you could pick your weather?

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Yes, we had Wesmar stabilizers installed after we retired. We still pick our weather windows, but the difference for us is that at 1.6 meters on the beam the trip is very smooth, 2 meters OK. Without stabilizers 2 meters is painful.

BandB said:

What is your definition of a decent catamaran? Give me an example of one that currently is built.

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As a start

Custom Aluminium Catamaran: Power Boats | Boats Online for Sale | Aluminium | Western Australia (WA) - Qld | Boats Online

Or

Wave Piercing Catamaran 22.5m For Sale | Ensign Ship Brokers
or
1995 Awesome Boats - New Zealand Custom Power Catamaran MY Power Boat

BandB said:

What is your definition of a decent catamaran? Give me an example of one that currently is built.

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To me the Horizon PC60 is at least half-decent! Although I have not been aboard one let alone cruised on one. If like sailing cats they might corkscrew a bit, and yes stuff would need to be bolted down vs a stabilised mono.

BandB said:

. We don't want to just cruise around the bay. Nothing wrong with doing that but "we have places to go, things to see."

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Same here and we are only cruising the bay in ours until we have ironed the bugs out and sorted the house, car, etc out.

I have done extensive miles, even ocean crossings on unstabilized boats where I would never consider having them.
Of course we had to wait for a weather window to open and go, but if living aboard full time with no time constraints surely its simply a matter of enjoying one idealic anchorage a bit longer before moving on to the next.

Simi 60 said:

Seems to me a decent catamaran would solve those issues

We don't have either and after near a year cruising around the bay in mostly ideal conditions (as we have no time constraints) haven't considered them.

For those that have them, would you need them if time wasn't an issue and you could pick your weather?

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You mean in a perfect world?

Obviously not.

Capt.Bill11 said:

You mean in a perfect world?

Obviously not.

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Wouldn't need them on a pond either.

Capt.Bill11 said:

You mean in a perfect world?

Obviously not.

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If your definition of a perfect world is one where you have no time constraints so can wait for the right weather window before moving to the next ideallic anchorage then I guess we live in a perfect world.

We have enough supplies and food gathering abilities on board to wait out several weeks of bad weather if needs be.
No rush. No deadlines. No where of importance to be.

Simi 60 said:

Same here and we are only cruising the bay in ours until we have ironed the bugs out and sorted the house, car, etc out.

I have done extensive miles, even ocean crossings on unstabilized boats where I would never consider having them.
Of course we had to wait for a weather window to open and go, but if living aboard full time with no time constraints surely its simply a matter of enjoying one idealic anchorage a bit longer before moving on to the next.

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Why would you never consider having stabilizers on an ocean crossing?

Woodland Hills said:

Why would you never consider having stabilizers on an ocean crossing?

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Because as we had no deadline we could and have waited for a weather window where they are not required.
We have done several 600nm passages in almost glass out conditions or conditions not bad enough to spill drinks by simply waiting a few weeks.

Simi 60 said:

Because as we had no deadline we could and have waited for a weather window where they are not required.
We have done several 600nm passages in almost glass out conditions or conditions not bad enough to spill drinks by simply waiting a few weeks.

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Have you ever operated a boat with stabilizers?

Some of us don't choose to wait weeks when the conditions are not at all unsafe and not uncomfortable with stabilizers. There is a huge range of conditions between uncomfortable and unsafe and stabilizers help reduce that range. Some of us also cruise in areas that one could never depend on a 600 nm passage in glass conditions. I've never seen a time that I could cross from Key West to Cancun or across the Gulf of Mexico or the Gulf of Alaska and be sure, even if the conditions were like glass, that they would remain that way. I've never even known the Gulf of Alaska to be that way, although it may be sometime. We don't want to sit longing for the Bahamas because crossing the gulf stream won't be "perfect." We lived on a lake previously and the only time to be sure of such conditions there was when no other boats were out. That brings me to a point, what about the wakes of other boats? Or do you wait for weeks until no other boats are out?

BandB said:

Have you ever operated a boat with stabilizers?

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I have done deliveries and been on boats with them and boats without them and sure, in shitty conditions the ride was superior on those with them but my point still stands, the only reason we were in shitty conditions was that these people had a timeframe ie: to get back to work

I don't go on boats that have timframes anymore.

Some of us don't choose to wait weeks when the conditions are not at all unsafe and not uncomfortable with stabilizers

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Don't you ever anchor to see the sights?
That's what we do when waiting, its not as if its wasted time, the boat doesn't have to be moving 24/7

That brings me to a point, what about the wakes of other boats? Or do you wait for weeks until no other boats are out?

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We are in the 3rd largest capital city in Australia on the last day of a public holiday.
I look to the horizon and see zero boats.
During the week when everyone is back at work I see even less

Reality is we don't feel wash from other boats and we only start to get uncomfortable ( things moving on the bench top) if more than 25knots on the beam.
I'm guessing 6 ft draft and 75 tonnes is stability in itself.

Simi 60 said:

If your definition of a perfect world is one where you have no time constraints so can wait for the right weather window before moving to the next ideallic anchorage then I guess we live in a perfect world.

We have enough supplies and food gathering abilities on board to wait out several weeks of bad weather if needs be.
No rush. No deadlines. No where of importance to be.

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Then you've answered your own question.

Simi 60 said:

I have done deliveries and been on boats with them and boats without them and sure, in shitty conditions the ride was superior on those with them but my point still stands, the only reason we were in shitty conditions was that these people had a timeframe ie: to get back to work

I don't go on boats that have timframes anymore.

Don't you ever anchor to see the sights?
That's what we do when waiting, its not as if its wasted time, the boat doesn't have to be moving 24/7

We are in the 3rd largest capital city in Australia on the last day of a public holiday.
I look to the horizon and see zero boats.
During the week when everyone is back at work I see even less

Reality is we don't feel wash from other boats and we only start to get uncomfortable ( things moving on the bench top) if more than 25knots on the beam.
I'm guessing 6 ft draft and 75 tonnes is stability in itself.

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You apparently have the worlds most perfect boat and only boat in the worlds most perfect conditions.

Capt.Bill11 said:

You apparently have the worlds most perfect boat and only boat in the worlds most perfect conditions.

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Hell no, she rolls like a pig in the wrong conditions, 25+ on the beam
Trick will be not to have her in those conditions and on the odd occasion when we have been we change course and tack to where we need to go.

She spent 30 years prior to conversion as an unstabilized gulf trawler working 1000nm from her home base so I would think that she can handle some slop.

Well, Simi, I guess it boils down to it, that you have a boat that is almost a ship, and an idyllic lifestyle that allows you to avoid almost all shitty weather, so you never need stabilisers.

But for mine, if I had the money to be out in a boat full time, I'd have stabilisers. My preference now would be the gyro type I think, because I am a bit nervous about the idea of appendages sticking out which could hit things. Ok, I know, not likely but it has happened. Also the effectiveness in a rolly anchorage, without mucking around with flopper stoppers, or the mechanical noise and wear on active fins, which are not as effective at anchor anyway I understand. But I don't, so I won't...but good on those who can, and do.

Peter B said:

active fins, which are not as effective at anchor anyway I understand.

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They are very effective at anchor.

Capt.Bill11 said:

They are very effective at anchor.

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Aren't they a bit noisy at anchor and don't you have to keep the genny running the whole time?

Woodland Hills said:

Aren't they a bit noisy at anchor and don't you have to keep the genny running the whole time?

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Yes. In that regard they are like a gyro system. Any form of active stabilization at anchor requires a power source, and some degree of accompanying noise.