Stabilizers: A Must for Passage-Making?

[N4061]

Stabilizers

We owned three Nordhavn's and one Helmsman trawler. Two of the Nordhavn's had active fin stabilizer systems (NIAD & TRAC) and we would not own a full displacement hull boat without them. On the smaller N35 (semi-displacement) there was not really a need for them based on the how the boat was being used. When we decided to build a simpler boat for the ICW we specifically did not want (or need) stabilizers for that trip but after cancelling the ICW and boating around southern California we missed the stabilizers. Any time you are in a beam sea of any size you will wish you had some type of system to reduce the roll. While some people can live without them I would argue if you are planning long voyages off shore why wouldn't you want to maximize comfort? The down side is cost but what is the percentage of stabilizers to the total cost of the boat? Likely less than 10% today so if you can afford the boat you can likely afford the value / comfort of this additional system. If 10% is make or break owning the boat then you may want to reconsider the boat you are looking at. Just my two cents for what its worth.

John T.

 

[slowgoesit]

For sure my earlier comment was done in jest. The following is not.
I would think one of the more attractive reasons for having/keeping paravanes would be for anchoring. For those of you with paravanes, can you expand on the value of paravanes for anchoring? I would think that two flopper stoppers, at the end of those long poles, would be a dream for anchoring and should be considered in this discussion for the purpose of comfort and passage making.

We will deploy the outriggers and paravanes if we are anchoring in an area with a confused state, for instance opposing current and wind/waves, or if near a channel with lots of idiots who don't know how to slow down around other boats. The boat came with flopper stoppers as well, which can be hooked to the cables after the paravanes are removed, but we've never had occasion to actually use them, as just using the paravanes, without having to remove them, and install the flopper stoppers is much easier. The paravanes dramatically reduce the roll at anchor, just like they do underway.

Anyone want to buy a nice set of flopper stoppers? They're probably 25 years old and have never been used, as the previous owners never saw the need to use anything other than the paravanes either. . . . One of these days I may just try them out and see how they do!

 

[sjisailor]

Question for you Hippocampus: You did an amazing amount of research and thought in your selection, and I'm guessing you talked to a lot of people. What do you believe is the main reason people chose Gyro/Seakeeper over, say fins? Easy option offered by the builder? No appendages? At-anchor stability? Or the inverse - why do people chose fins over gyro? I totally understand why paravanes don't get much notice on a new-build, but curious what problem folks are trying to solve when they make a choice between Seakeeper and Fins. I doubt cost is much of a factor given the overall expense of a new boat so there must be a functional or perceived reason why someone choses one over the other. For me, my only gripe with gyro is the persistant power requirement - no other issues. The oft-touted disadvantages of 30-min spin-up time and maintenance costs are false flags as far as I'm concerned as they are both easily incorporated into a normal usage cadence and would not alter my cruising lifestyle (running generator full-time would change my style, but that's just me).

Thoughts?

Peter

For my 0.02 the advantages of gyro vs fins are for anchorage and lack of protrusions. Would really hate to hit something with them. But then I don't have either now ... yet am planning gyro for next boat which is waiting to be built (40' SD). Agreed about the generator issue as main drawback. Also loss of space.

 

[mvweebles]

For my 0.02 the advantages of gyro vs fins are for anchorage and lack of protrusions. Would really hate to hit something with them. But then I don't have either now ... yet am planning gyro for next boat which is waiting to be built (40' SD). Agreed about the generator issue as main drawback. Also loss of space.

For your information, the hydraulic tank for fins is about 10 gals - with valves and hose connections, a decent size. Plus the hydraulic hoses and pumps- space penalty for sea keeper probably isn't as great as you'd think, especially since a new build has it designed into the layout. Electric actuators would be very interesting.

For your planned boat, would you share the approximate price difference between fins and gyro? Even just a rough percentage?

Fins have a long, long history of reliable service (my 50 year old Vospers worked okay despite being 20+ years out of support). But fins do occasionally hit something that causes damage despite being designed to breakaway. I guess paravanes do too (or suffer a rigging failure similar to sailboats). I wonder if after 50+ years if gyros will have a similarly rare catastrophic failure history such as bearing failure causing the high RPM gyro to tear itself to smithereens even though I'm aure they have failsafe measures designed into them just as fins supposedly do. Time will tell.

Thanks for sharing. Good luck on your build. Exciting times!

Peter

 

[Simi 60]

The down side is cost but what is the percentage of stabilizers to the total cost of the boat? Likely less than 10% today so if you can afford the boat you can likely afford the value / comfort of this additional system. If 10% is make or break owning the boat then you may want to reconsider the boat you are looking at. Just my two cents for what its worth.

John T.

Gee, if it was10% of our buy price I'd be all over it
To go active fins would cost more than the boat
Fuel tanks would have to come out and be reconfigured
To do that there is major surgery, like cutting the cabin off type of surgery

Gyro not as drastic but there would be cutting half the galley out
Cutting a larger hole in the floor
Cutting out all the foam and fibreglass in the cold room
Still going to cost near $100k to get there.

 

[Hippocampus]

Was draft restricted for 35+ years cruising a variety of sail. Now interested in skinny water along US east coast and Bahamas. People talk about hull damage from fins but don’t believe that’s a concern being so rare an occurrence. Rather do think any appendage makes it harder to disengage from a grounding and any appendage can be struck or fouled by debris. Although we owned this boat for a short time have already found Chesapeake mud once. Came into Deltaville in the total black tired at 3 AM. Trying to figure out which was our assigned slip ran aground. Knew bottom was mud so with 540hp just slid along until we were floating again. Didn’t want to back for fear of sucking up mud into the engine intake. Think that would harder to do with fins. Similarly chose a single screw. Nothing to do with efficiency but rather protected running gear. Already have gone through the C&D several times with her. Once there was a remarkable amount of logs, branches and othe debris in the water.Clunk, clunk and clunk. Tried to dodge what we could but a moonless night. Boat got hauled at Deltaville for other work. Not even a scratch.
To date we haven’t run the gyro at anchor. But rather using two snubbers have adjusted how the boat sits in relation to the waves. Have been thinking about doing a steady sail but have my panels up there and want no shadows. The boat is SD so sits more on the water than in it c/w prior sail. The problem with her is due to the strakes there’s a bow slap which is annoying at times. Some have used micro beads to fill in the strakes to get rid of that slap.
Have not seen serious weather with her yet and probably never will. But have seen very annoying chop. Days of massive swells with wind waves on top are hopefully over. Remain totally amazed how well the gyro does for that kind of chop. Stuff in the 3 to 5 range. Short period and usually not that rhythmic.
The gyro sits in the middle of the stern under the access hatch for the lazerette. There are two other hatches to either side. It does make the boat slightly stern heavy. Have stored other things forward to compensate but still needed to move the boot strap and bottom paint upon purchase. Lost of space isn’t meaningful to us given where it is and have access to it on all sides.
Seems I’m saying this repetitively I wouldn’t choose a gyro if my emphasis was on passage making. But for coastal there’s more upsides then down c/w other choices imho.

 

[rslifkin]

Was draft restricted for 35+ years cruising a variety of sail. Now interested in skinny water along US east coast and Bahamas. People talk about hull damage from fins but don’t believe that’s a concern being so rare an occurrence. Rather do think any appendage makes it harder to disengage from a grounding and any appendage can be struck or fouled by debris. Although we owned this boat for a short time have already found Chesapeake mud once. Came into Deltaville in the total black tired at 3 AM. Trying to figure out which was our assigned slip ran aground. Knew bottom was mud so with 540hp just slid along until we were floating again. Didn’t want to back for fear of sucking up mud into the engine intake. Think that would harder to do with fins.

It depends on how deep the fins are relative to the rest of the boat, so it's a bit specific to a given installation. On many I've seen the fins end a little higher than the keel, so you'd be well into the mud before the fins hit.


To some degree for a retrofit, it really depends on what fits the boat best. I couldn't put a gyro on my boat easily, as there's really nowhere to put the thing. But fins (especially with electric actuators) could be done fairly easily, as there's not much in the way of where the fins would go.

 

[Hippocampus]

Although not Britain where bilge keels are popular as you dry out with the tides there’s a fair bit along the bay of fundy that’s similar. We wandered on motorcycles around that area and the admiral wants to return on a boat. You’re right different boats different solutions but think a gyro might be preferred if you expect to dry out with the tides on occasion regardless of hull conformation.

 

[mvweebles]

Trying to figure out which was our assigned slip ran aground. Knew bottom was mud so with 540hp just slid along until we were floating again. Didn’t want to back for fear of sucking up mud into the engine intake. Think that would harder to do with fins. Similarly chose a single screw. Nothing to do with efficiency but rather protected running gear. .

Good post. Thanks for taking the time to explain your priorities. Makes perfect sense and goes to show how each situation is different, and how we each assimilate prior experiences.

Years ago we were cruising the Delta region towards Sacramento. We'd taken a side slough that rejoined the main river 10-12 miles up. When we went to rejoin the river, there was clearly a serious silted sandbar. Rather than backtrack, we plowed right through creating a chocolate milkshake in our wake. Never occurred to me the fins might impede our progress, or that we might ingest silt. Ignorance is bliss I guess.

Peter

 

[rslifkin]

Although not Britain where bilge keels are popular as you dry out with the tides there’s a fair bit along the bay of fundy that’s similar. We wandered on motorcycles around that area and the admiral wants to return on a boat. You’re right different boats different solutions but think a gyro might be preferred if you expect to dry out with the tides on occasion regardless of hull conformation.

That, or see if the fins could be made strong enough to use as legs to keep the boat upright.



Of course, it's a total non-issue on my boat with twins and a somewhat shallow keel. The props stick down a few inches below the keel, so some extra caution is already warranted in shallow water and drying out would require use of a tidal grid or other careful prep to avoid putting the props into the mud.

 

[Marco Flamingo]

I haven't yet thought of a Henny Penny fear of paravanes but I'm sure that there is one.

I did find an article that talks of the dangers of paravanes. It is a study by Dr. Bass, a proponent of anti-roll tanks, so of course it concerns a comparison between paravanes and ART. Roll Stabilization for Small Fishing Vessels Using Paravanes and Anti-Roll Tanks, 1998. After a little scare story about the dangers of paravanes, ART wins.

But . . . . an ART has to be designed for a specific boat. I don't see that as an insurmountable complexity, but "tuning" seems to bother some. Also the tank weight aloft. That is odd when one considers the weight aloft aspect of paravanes (which the paravanes, once deployed, also have to counter act). A paravane system for my boat would be 1,000 pounds (assuming electric winches), all of which would be above the center of gravity. An ART for my boat (Dr. Bass says 1.5 -2.5% of vessel displacement of on the flying bridge) would be 202-337 pounds aloft. Yes, an ART is additional weight aloft, but a paravane system could easily be three times as much.

But my interest in the article is mainly the numbers. That's what is almost always missing in the discussions on TF (and in advertising literature.) Dr. Bass took readings with and without the stabilization systems (paravanes or ART) deployed. Numbers generated from models in a laboratory tank are interesting, but I prefer real-world tests. Of course the testing was on working fishing boats and they don't have time to mess around with special "test runs." They are on their way to fishing grounds and on their way back from fishing grounds (hopefully full of fish). The scientists onboard are welcome to get the numbers if they don't get in the way.

For running stability measurements, one needs a way to accurately measure the system's effect. Dr. Bass employed a "gyro-chip roll rate inclinometer with vertical referencing." I'm guessing that was a relatively uncommon and expensive piece of kit in 1998. But now, everybody reading this thread can have one onboard. I use a free app on my phone. The only downside I can find to the app is that it doesn't record. You have to be looking at it to see that what I would in the past have called a 15 degree roll was really only 9 degrees. Damn reality getting in the way of a good story.

But like my other free phone apps (vibrometer and decibel meter) it keeps things real. I place my phone in the exact same place on the helm and use the apps to measure changes in vibration (did that log actually hit the prop?), sound (did that valve adjustment reduce noise?), inclinometer (how much did the $12,000 paravane system effect roll and pitch?).

According to the study, ARTs outperformed paravanes across the board. And not just from an economic aspect, which is generally ignored because of a lack of data. If a $200 system reduces the roll by 20% and a $12,000 system reduces roll by 30%, which is most effective? But the study does mention other ART advantages: nothing to deploy, maintain or flip the boat over (in the case of Straits Pride ll studied in the article). The actual real-world roll reduction of ART was only around 50%, but the period was also extended, making the stabilization seem greater than the numbers showed.

My boat has a large beam to length ratio, giving it what is sometimes called "excessive stability." (Naval architect Weston Farmer said a boat should not exceed 35% beam to length. I'm at about 37%) Others call excessive stability a fast roll or snap. Damping the amplitude of the roll is generally the goal of stabilizer systems, but slowing the frequency would also be appreciated on my boat. The study shows both aspects of ARTs.

As to the original post, are stabilizers necessary for cruising? No. I'm reading The Voyages of Captain Cook right now. He's on his last round-the-world voyage and still nothing about stabilizers. Would it have made his third voyage more pleasant? Given that he is about to get whacked in Hawaii, stabilizers would not have made any difference.

 

[jimdavi]

Really good fin discussion. I added fins to our NP specifically for my wife. She gets afraid when the boat rocks and for me, her being afraid is not good for our boating.

We had our fins mounted as far outboard but not impede with the beam, and did that successfully. There is a lot of clearance between the keel and fins. I’ve seen other installations with the fins quite low. They are more effective the way we installed them.

Jim

 

[Mako]

Unsure if this TSB (Canada) report was cited earlier, but the findings were that loss of a paravane contributed to sinking of this fishing vessel. Likely not entirely relevant to recreational vessels, but mostly a lesson learned (again and again) about down-flooding.

http://tsb.gc.ca/eng/rapports-reports/marine/1998/m98n0064/M98N0064.pdf

 

[Airstream345]

You guys are forgetting about one of the oldest stabilizers around....sails

Seriously, we've been experimenting the use of our sails this season and find it reduces roll about 40-50%. Generally if you're rolling 10-15 degrees to port and 10-15 degrees to startboard in a beam sea and wind deploying just the main and mizzed almost eliminates the rolling on the windward side. Not perfect but much better and stuff stops crashing down below.

Even with our ketch rig sail plan which is more than most steadying sails on most trawlers, we are still considering paravanes. For us it's a simple, proven passive stabilization that has many advantages over fins....lower maintenance, easy to inspect without a haul out, use at anchor (which we do a lot) and repairable/replacable in almost any port where you can find SCH 40 pipe and a welder.

For those arguing paravanes could flip/sink the boat, often referencing the Canadian fishing boat there are at least three examples of holed hulls from fins breaking grounding I can remember since joining this forum...the most recent was a Grand Banks in Alaska.

Everything on a boat is a compromise and this is no different. I've been turned off of active fins for my own reasons. Others love them. It's cool...we're all still boating.

 

[ranger58sb]

I did find an article that talks of the dangers of paravanes. It is a study by Dr. Bass, a proponent of anti-roll tanks, so of course it concerns a comparison between paravanes and ART. Roll Stabilization for Small Fishing Vessels Using Paravanes and Anti-Roll Tanks, 1998. After a little scare story about the dangers of paravanes, ART wins.

When I first read Beebe, I began to think a combination of an anti-roll tank and bilge keels might be the bee's knees for semi-stabilization on a very reduced budget.

You guys are forgetting about one of the oldest stabilizers around....sails

Haven't forgotten. Haven't figured out where to put the mast(s). See avatar.



-Chris

 

[Mako]

When I first read Beebe, I began to think a combination of an anti-roll tank and bilge keels might be the bee's knees for semi-stabilization on a very reduced budget.

If I recall correctly, rolling chocks/bilge keels are counterproductive with flume tanks. @Marco may have more info on that from his readings.

 

[cardude01]

We still like our steadying sails. When we crossed the GOM from Tampa to Pensacola last year we had the sails up for the entire 52 hour run, and they made a big improvement in roll. At night I just sheet them in tightly and reef them if it looks like weather coming.

Big enough steadying sails are not easy to install on most boats obviously, but ours was already pretty set up for such a thing.

I still absolutely love the KK54. One of the all time sexy-cool boats IMO.

 

[Marco Flamingo]

If I recall correctly, rolling chocks/bilge keels are counterproductive with flume tanks.

I think that's probably right, although I haven't seen much about using them in tandem. Rolling chocks/bilge keels would slow the roll and then the water wave in the tank would definitely be too fast, requiring further complexity in the tank baffle system.

I still haven't seen an explanation why every ART doesn't have adjustable baffles. Another design feature I haven't seen is some kind of a dual tank system. A small tank could have a free wave arrive too fast, but that action would trigger a simple release of the water momentarily held in the larger tank. I need to channel my inner Rube Goldberg.

I also haven't seen anything discussing ART using a liquid other than water. It seems fresh and seawater have been tried. But not "Dead Sea" water, i.e., super dense and viscous water from adding various salts. That would also have a "tuning" effect. This gentleman may be reading all about it.

 

[KnotYet]

I think that's probably right, although I haven't seen much about using them in tandem. Rolling chocks/bilge keels would slow the roll and then the water wave in the tank would definitely be too fast, requiring further complexity in the tank baffle system.

I still haven't seen an explanation why every ART doesn't have adjustable baffles. Another design feature I haven't seen is some kind of a dual tank system. A small tank could have a free wave arrive too fast, but that action would trigger a simple release of the water momentarily held in the larger tank. I need to channel my inner Rube Goldberg.

I also haven't seen anything discussing ART using a liquid other than water. It seems fresh and seawater have been tried. But not "Dead Sea" water, i.e., super dense and viscous water from adding various salts. That would also have a "tuning" effect. This gentleman may be reading all about it.

The obvious fluid of choice would be mercury, which is used as a variable
counterbalance in some old-school movie studio cranes.
I must say it always made me a bit uncomfortable being around so many
gallons of the stuff!

 

[ksanders]

My experience with semi-displacement boats is that comfort and sea keeping abilities increase with speed. I think Kevin has made this point before. The form stability underway comes in large part from the lift that's provided at higher speeds.

I think that's a benefit of SD designs that's not talked about much. The higher speed capabilities often can be used to increase comfort and control in moderate conditions.

Sent from my moto g play (2021) using Trawler Forum mobile app

This idea of stabilizing the boat by burning fuel cannot be overstated.

If the seas create a uncomfortable roll it is as easy as applying power to significantly reduce that roll.

Yes, that application of power costs money in diesel fuel. Yes it reduces the boats range. That said every roll reduction technique has costs and drawbacks associated with it.

 

[rslifkin]

This idea of stabilizing the boat by burning fuel cannot be overstated.

If the seas create a uncomfortable roll it is as easy as applying power to significantly reduce the roll.

That option depends on the hull shape. FD hulls don't have that option. And on a long enough run, it's not necessarily viable due to fuel burn vs fuel capacity. Plus, a good stabilization system can knock roll down even more than extra speed does (on plane you still get a series of well damped tilts as the waves pass under).

 

[GoneDiving]

But . . . . an ART has to be designed for a specific boat. I don't see that as an insurmountable complexity, but "tuning" seems to bother some.....

An ART would seem to be very simple to mock up, test and tune. Certainly much simpler than a dummy paravane or bilge keel. The biggest challenges would be ensuring one has the structural support for ~1t of moving fluid and the physical space to do it.

Given the DIY nature of many boaters, I'm wondering has anyone given it a go?

 

[HypnoBob]

I may have missed this in earlier posts, but the gyro stabilizers are an excellent option, e.g., Seakeeper.com

 

[Marco Flamingo]

The obvious fluid of choice would be mercury

Funny, I looked at that. The viscosity of mercury is 1.6 times that of water, which would probably slow the weight transfer just right! It is also 13.5 times heavier. Sounds perfect. The tank would be about 6" x 6" for my boat, so a big space savings! I would need about 270 pounds at today's spot price of $3,363 per pound. That would be just over $900,000 (not counting the tank and installation). Figure about a million dollars. I'd have bragging rights at the yacht club. "Gyro stabilizers, Bah!! I spent more than that!"

How much farmed salmon would I need to get that amount of mercury?

>the structural support for ~1t of moving fluid and the physical space to do it<

A ton of water might be required for boats over 65 feet. Most studies find about 2% of gross weight is enough, depending on placement. For my 30' trawler, I'm looking at about 270# or the equivalent of 2 skinny people walking on my flying bridge. Required volume of water would just over 5 cubic feet (32 gallons). My flying bridge seat box is 40 cubic feet. Space isn't a big issue.

 

[socalrider]

A ton of water might be required for boats over 65 feet. Most studies find about 2% of gross weight is enough, depending on placement. For my 30' trawler, I'm looking at about 270# or the equivalent of 2 skinny people walking on my flying bridge. Required volume of water would just over 5 cubic feet (32 gallons). My flying bridge seat box is 40 cubic feet. Space isn't a big issue.

I'm still curious how the system would respond to a long slow roll, below the natural roll period of the boat, e.g. from a downwind run not perfectly perpendicular to a wave. Seems this would result in the liquid all on the low side, exacerbating a roll and significantly reducing stability, particularly if it was up high on the flybridge.

 

[Marco Flamingo]

I'm still curious how the system would respond to a long slow roll, below the natural roll period of the boat, e.g. from a downwind run not perfectly perpendicular to a wave. Seems this would result in the liquid all on the low side, exacerbating a roll and significantly reducing stability, particularly if it was up high on the flybridge.

Sure, definitely possible if the tank was huge. Maybe 25 to 30% of the gross weight instead of 2%? I'm not sure that you would notice any extended roll period otherwise. If two people sitting on the same side of a flying bridge feels dangerous (three people for your boat), then the boat probably can't handle an ART.

I can't explain why people think 300# of liquid in a tank on the FB is dangerous but 1,000 pounds of paravane rigging/equipment high aloft isn't. Or maybe those with undeployed paravanes notice the exacerbated roll and significantly reduced stability but stay silent.

 

[socalrider]

Sure, definitely possible if the tank was huge. Maybe 25 to 30% of the gross weight instead of 2%? I'm not sure that you would notice any extended roll period otherwise. If two people sitting on the same side of a flying bridge feels dangerous (three people for your boat), then the boat probably can't handle an ART.

I can't explain why people think 300# of liquid in a tank on the FB is dangerous but 1,000 pounds of paravane rigging/equipment high aloft isn't. Or maybe those with undeployed paravanes notice the exacerbated roll and significantly reduced stability but stay silent.

My boat is about 30,000lbs so that would be 600#. I don't know that I'd want 4 people running to the low side of my flybridge in synch with a scary slow roll, but I see your point that it's probably pretty marginal in terms of AVS.

I don't think paravanes for my boat would come in at anywhere near 1000lbs. Maybe 200lbs? I'm not really sure, but AL poles and SS wire or dynama don't weigh that much.

 

[mvweebles]

I gotta ask: where is the naval architecture theory and actual application on these anti-roll tanks? Best I can tell, a Roughwater 58 installed one 20+ years ago and generated a few articles - including some discussing difficulty in "tuning" the tank (read: it didnt work well so tweaks were atrempted). More or less nothing since then except some table-top meanderings.

What am I missing? Seriously, what makes this a viable form of stabilization for recreational trawler style boats in the 40-60 foot range?

Peter

 

[Marco Flamingo]

I don't think paravanes for my boat would come in at anywhere near 1000lbs. Maybe 200lbs? I'm not really sure, but AL poles and SS wire or dynama don't weigh that much.

It would be interesting to get a number. Kind of odd that nobody seems concerned enough to publish numbers. The systems that I've seen had a stout mast and two outriggers, easily 200# of aluminum. Then electric winches (four in one setup) at 50# each? 20 feet of chain each side. Tackle and 100' of wire cable. I think 1,000# is close. All dead weight well above the top of the pilot house (where an ART would be). Then the weight of the fish themselves (usually stored closer to the CG). If one is worried about reduced stability because of weight aloft, it's a good thing that there are paravanes to deploy to correct for that.

 

[Marco Flamingo]

I gotta ask: where is the naval architecture theory and actual application on these anti-roll tanks? Best I can tell, a Roughwater 58 installed one 20+ years ago and generated a few articles - including some discussing difficulty in "tuning" the tank (read: it didnt work well so tweaks were atrempted). More or less nothing since then except some table-top meanderings.

What am I missing? Seriously, what makes this a viable form of stabilization for recreational trawler style boats in the 40-60 foot range?

I've seen the articles on the Swan Song, although not the ones on the difficulty in tuning the tank. The articles I've seen is that the tank was designed prior to installation and no additional tuning was done. I haven't seen any "tweaks were attempted" articles. The owner (and now his son, I think) have had nothing but good things to say despite having been in some rather hairy conditions. Other articles are mainly fishing vessels with satisfied captains.

I agree that ARTs aren't common. But then how long were paravanes in use before they were adopted by recreational trawlers in the 40-60' range? Give up? They were introduced by the Royal Navy in 1916. Originally used to snag mines, they now snag logs. But they were still adopted by recreational boats 60 years later. Does that delay/maturation mean that they aren't a viable form of stabilization?

There are definitely some impediments to the adoption of ARTs. First, there's no profit margin. Second, it certainly isn't glamorous. Third, the physics aren't straight forward. Still lots of concern about the water tank flipping the boat over. Forth, there are limitations to its effectiveness. An honest 50% reduction in the boat's roll doesn't seem like enough when other systems claim 95%.

Maybe the idea just needs time to mature. Don't know, but I'm not writing it off.