which stabilizers for us?

I know this has been discussed before, but everybodies situation is different. Here's mine.

Well, the admrial does not really like the roll of our boat in the open ocean, in a beam sea.

Here's what happens.

In a moderate beam sea of around 4' (long ocean swells) which is pretty common on a nice day our 4788 gets into what I've heard describes as "parasitic rolling". This is most pronounced at rest (when we're fishing), and continues through displacement speeds. Running the boat harder, say 13-14 knots causes the stern to squat and the rolling stops.

What I've noticed is that the seas are timed just right for the natural roll period of our soft chined boat and the rolling seems to be magnified. Its amazing just how much this boat rolls in what seem to be pretty calm seas. Actually it rolls more than our old 28' cabin cruiser in these specific conditions.

Because of this I'm going to invest in some kind of stabilization.

I have a quote from the folks that make the Mitsibushi gyro type unit at $43K. Installation would be really easy. I'm skilled enough to do the job no problem. I have room for the beast in the lazarette right over a couple of stringers. This would produce significant roll reduction both at rest and under way. The most roll reduction is in the exact seas I'm describing. I have a simulation from Mitsubishi with graphs I'll try to figure out how to post.

Another option is the Naiad stabilizers. I've talked with the folks at Naiad and am having my favorite boatyard work up a estimate. I'm assuming the estimate will be in the same ballpark, possibly a tad more.

The mitsubishi seems to fill my needs better, but its a newer technology. The fins are proven technology, but won't help while fishing, or at anchor.

Which one would you go with???

I went for sails since other (centrifugal or fin) were impractible spacewise in a mid-30-foot boat, and apparently for the sixth of the cost of your gyro.

Fins only work while moving through the water. Gyroscopes don't need boat movement to work, but I wonder how much they can eliminate roll in significant seas. While drift fishing, perhaps a sea anchor strategically employed might help. (Strangely, I expect to be tossed about while in the open sea.)

Severely wrenched my knee on this 900-plus-foot ship with stabilizers during 50-something-foot waves.

Very hard to stop roll at rest . Gyro maybe?

The flopper stopper style rigs can use special sinking platforms that seem to work.

If you are anchored , a second anchor could make it a pitching motion.

Very common in the Carib. behind a smallish island.

FF said:

Very hard to stop roll at rest . Gyro maybe?

The flopper stopper style rigs can use special sinking platforms that seem to work.

If you are anchored , a second anchor could make it a pitching motion.

Very common in the Carib. behind a smallish island.

Click to expand...

Im leaning towards the gyro. That way drift fishing is doable.

Right now I have to set the anchor to fish. Then the boat weathervanes and no beam seas. If I drift then the boat naturally turns beam to the wind and waves.

along these lines.....do the wing keels (small keel-like runners 8-10" tall located about 1/2 way between true keel and chine) that some sailboats have, work well at sea? Would they be a worthwhile addition to a trawler? I have seen two trawlers with them but couldn't find owners to inquire.

I'm sure that isn't the term for them, and I'm not asking about a true wing-keel i.e. the horizontal foil on the bottom of sailboat keels.

Kind of like what is seen in post 98 in the link below. Maybe not as big though, that size may be what is required to gain appreciable effects.
http://www.boatdesign.net/forums/boat-design/twin-keel-research-5315-7.html

Greetings,

Bilge keel - Wikipedia, the free encyclopedia

Thanks RT exactly what I was meaning.


"A bilge keel is constructed from flat plate so as to present a sharp obstruction to roll motion. The roll damping provided by a bilge keel is more than that of a barehull ship, but falls short of other roll damping devices. Nevertheless it is considered prudent naval architecture to install a bilge keel whenever possible as it is the only device effective in the severest of seas."

ksanders - have you seen this thread on the Bayliner owners forum:
soft chines, hard chines and underhulls [Archive] - BAYLINER® OWNERS' CLUB

My gut feel is that the gyro will cost you a phenomenal amount of money, and that's not including the hull bracing required. And that's even if you found a place to mount it. IMHO you might be better off buying a second boat just for fishing!

Edit: just reread your original message (I had read it on my phone) and noted the $43K cost and that you feel you have the installation figured.

I'm now hoping you do go that route and give us an update once you've had a chance to use them! <fingers crossed for you>

refugio said:

ksanders - have you seen this thread on the Bayliner owners forum:
soft chines, hard chines and underhulls [Archive] - BAYLINER® OWNERS' CLUB

My gut feel is that the gyro will cost you a phenomenal amount of money, and that's not including the hull bracing required. And that's even if you found a place to mount it. IMHO you might be better off buying a second boat just for fishing!

Edit: just reread your original message (I had read it on my phone) and noted the $43K cost and that you feel you have the installation figured.

I'm now hoping you do go that route and give us an update once you've had a chance to use them! <fingers crossed for you>

Click to expand...

Thanks, I did read that thread, and might have participated in it.

Underhulls might work. But they might not work that well for me either. My favorite boatyard of course wants me to install underhulls and even a hull extension. They have quoted me $30K for the complete job.

I have a little challenge in converting my boat from a soft chined hull to hard chined hull. The soft chined hull has less initial stability, but more absolute stability. I'm concerned that the conversion would in the end make for a less seaworthy boat, when the going gets really tough.

I'm also concerned that if I spend the $$ I won't get the roll reduction I'm expecting and will still be dealing with this issue.

The gyro is pretty attractive right now.

I had a few spare minutes so I groveled the web looking for references to the ARG system and Seakeeper - there's a thought-provoking comparison on the Seakeeper site.

A few things to consider: the spool up time for the ARG is apparently 25 minutes, assuming you are talking about their ARG12500T you are at the uppermost end of the specified displacement, it consumes 3KW of electricity and since it's air cooled, that means you're going to have to deal with that heat in the lazarette (ok, might be easy in Alaska). 700 pounds in your lazarette might not be a problem, but if you talking about the next size up unit that's 1600 pounds.

I would also be very nervous about putting this much additional strain on the stringers without hiring some additional engineering, or seeing it proven in several other equivalent boat.

I'm still rooting for you do this so I can see what happens!

ksanders said:

My favorite boatyard of course wants me to install underhulls and even a hull extension.

Click to expand...

I know nothing about these boats, but there are a bunch in my club and I know that the hull extension is particularly appreciated.

ksanders said:

The soft chined hull has less initial stability, but more absolute stability. I'm concerned that the conversion would in the end make for a less seaworthy boat, when the going gets really tough.

Click to expand...

While that may be a common yardstick when comparing hulls of different design, I'm not sure it holds true here. If you add chines to an existing hull, my gut feel is that you're not significantly changing the metacentric height, and the only point at which the hard chine would work against you is if the CG passed outboard of the chine (a truly horrifying situation!). I'm not a NA, but you might want to look into this more.

What the chines will do is change the motion of the boat since it will resist initial rolling. And the resulting roll will be sharper. But I don't think it will negatively affect ultimate stability. Just a guess.

ksanders said:

I'm also concerned that if I spend the $$ I won't get the roll reduction I'm expecting and will still be dealing with this issue.

The gyro is pretty attractive right now.

Click to expand...

The chine modification is common, but I'm guessing you're going to be the guinea pig on the gyro for your boat. Frankly, that would concern me more.

refugio said:

The chine modification is common, but I'm guessing you're going to be the guinea pig on the gyro for your boat. Frankly, that would concern me more.

Click to expand...

That is my concern as well.

I'm not going to do the chine modification.

My choice is between stabilizers and gyro.

The stabilizers are a known quantity. I have even read reports about the improvement on my exact same hull.

The gyro, while having the opportunity for at rest roll reduction does not have the history, and the testimonials that fin stabilizers have.

I enquired of the naiad rep about their at anchor system, but from his description its not viable for my boat. Just one of the issues with it is the fact that it would use 8KW steady state.

Hello:

The attached photos show what a few owners of Campion 30 trawlers have done to calm down the roll a bit. The "wings" are aluminum plate I believe and owners say it does help. Never experienced myself because our Campion is wingless (and doesn't get much use since the Formosa joined the "fleet" last year).

Have you considered Paravane Stabilizers?

Cheep but effective.

Low tec.

Sd

skipperdude said:

Have you considered Paravane Stabilizers?

Cheep but effective.

Low tec.

Sd

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Not on my boat Dave.

If my boat were more commercial looking that would be a great solution.

ksanders said:

Im leaning towards the gyro. That way drift fishing is doable.

Right now I have to set the anchor to fish. Then the boat weathervanes and no beam seas. If I drift then the boat naturally turns beam to the wind and waves.

Click to expand...

Given what you have laid out, I think the gyro makes sense. It's new technology for the recreational market. I can't wait to hear your report.

ksanders said:

Not on my boat Dave.

If my boat were more commercial looking that would be a great solution.

Click to expand...

You see them on Nordhavens all the time. I wouldn't call them Commercial. What do I know.
It's only money. Spend it. Go for the Gyro see if it works.

There is the rub.
What if you don't like the way it works? Do they offer money back guarantee?

Anyone else with your kind of boat have one?

Sd

As most of you know I have looked and talked about twin keels, passive, more for added assurance the Eagle does not roll over if grounded/on the hard/grid as well as reduce the roll. Twin Keels are mostly on sail boats to eliminate the long deep center keel. http://www.kastenmarine.com/roll_attenuation.htm.

I have talked to Kastern, that has twin keels on many of his trawler designs. The twin keels would have a slight negative ballast, about 6 to 10 ft long, 2 ft tall, located between the pick up points of the engine room bulk work which is 50 to 75% to the stern. I would think in Alaska and Canada twin keels would be a big advantage?



Beteeen the fins and gyro I would go with the fin stabilizers. Some boat that have fins also have kilge keels to protect the fins.

The plot thickens

When I asked the mitsibushi folks if they had any test data for boats similar in size etc... to my boat I was told that they dont have any "smaller" boat installations documented. It seems that most boats are larger and use either a larger gyro unit, or use two of the smaller ones.

I have to be honest, this scares me.

What I think I'll do is either ask for a steep discount as a "test" boat, or ask for a money back refund clause as part of my purchase agreement, if I go this route. I really like the gyro concept, but I'm not interested in being installation #1 as a full price customer.

I've conveyed my concerns to the Misibushi folks and will see where this goes.

If I go with fin type stabilizers I KNOW that they will work. They just won't work while drift fishing, or at anchor.

$47,000 to reduce a boat's rolling seems.... well, lets put it this way, I can think of a lot of things I'd rather spend $47,000 on than to reduce the rolling of our boat.

But everyone's situation and priorities are different, particularly when it comes to keeping one's boating partner happy. If we bought another boat I'd have to pay to put in a second engine if it only had one just to keep my wife happy.

The chine sleeves that were mentioned earlier were designed---- so said the articles about them when the sleeves came out--- to make the soft-chine Bayliner hull more efficient at speed, not dig as deep a hole in the water at the stern, and lower the bow a bit. I doubt they will have the kind of reducing effect on roll that your wife would like. Our boat has a hard-chine hull as built, and while it doesn't have the deeper, slower roll that displacement boats have, it has a short, semi-violent snap-back roll that a lot of people think is far more uncomfortable.

Bilge keels can have an effective impact on roll but from what I've heard from people, including commercial people, who have them, the main benefit is roll rate reduction, not so much roll distance reduction although they do help some in that regard.

But if you want to reduce roll period, I think your only real choices are active or passive stabilizers. And since you believe your boat does not lend itself to passive stabilizers for aesthetic and perhaps other reasons, that leaves active stabilizers.

From all accounts I've heard from people with GBs who have them, a good active stabilizer system like Naiad can make roll pretty much go away except under very rough conditions. So that would seem to be your best bet for reducing roll underway.

As for stationary or drift fishing, active stabilizers aren't going to do much of anything for you, passive stabilizers (birds) could help a lot due to their long moment arms, and bilge keels could help somewhat. Don't know anything about the gyro system although in theory it could work very well when the boat is stationary. Or you could use a sea anchor to keep your boat pointed into the wind/waves while drift fishing.

But $47.000....... I dunno. You could buy a lot of dramamine for a tenth of that.

Marin said:

$47,000 to reduce a boat's rolling seems.... well, lets put it this way, I can think of a lot of things I'd rather spend $47,000 on than to reduce the rolling of our boat.

Click to expand...

Marin

Admittidly the cost is significant, but it is a cost that somebody had to bear for every stabilized boat out there.

The Naiad rep told me that the fins would reduce the boats roll by over 90%. That means a 15 degree roll (a pretty uncomfortable roll) goes to 1.5 degrees. That will make from a roll standpoint my boat feel like its at the dock.


If they make boating more comfortable for my admrial than the value is priceless. Its either that or she will never come with me far from the harbor, and harbor cocktails are not what I bought the boat for.

Oh, I understand the reasoning and have no quarrel with it. I have no idea if we will ever change boats but if we do the only kind we would get is a twin in large part because my wife enjoys boating a lot more with two engines under the sole. And what's a top quality 200-300 hp diesel cost installed these days---- $30k, $40k, more, added to the cost of a boat?

But for me, and fortunately my wife as well (meaning fortunate for me, too), nearly $50k to smooth out a boat's ride some is not a value-for-money proposition. Particularly when it's adding another system to take care of, which is why I like the idea of passive stabilzers if a boat will accomodate them.

But that's us. For someone else, if stabilizers make the difference between getting one's money's worth from a boat instead of simply using it as a floating cocktail tray in the harbor the cost of stabilizers becomes something worth spending.

It's sounding to me like Naiad or equivelent stabilizers are what's going to fill your bill the best although they don't address the still or drift fishing part of the equation.

Follow your gut, but aren't you facing an uphill battle?

Still, if you're drifting while fishing, I'll say again a wisely-employed sea anchor is worth pursuing. Wonder what you will do with ocean swells causing the boat to constantly rise and fall despite attempts to eliminate roll.

There's nothing like a 900-foot-plus vessel to help eliminate rocking and rolling.



Sorry, no fishing!

NAIAD's new At Anchor system will work when drifting or anchored. Yes, you would need to have the genset running...but this is true of the gyro also when at anchor. Reportedly, roll damping by NAIAD underway is more effective than that of gyros.

Unless you have some innate bond to your boat, this could be an ideal time to seriously look at another boat you've been lusting after. Dropping $50K on a single system on a not new boat (I don't know the age/value of your boat), would go quite some distance to rationalizing a boat upgrade with some features you've found you'd really like to have (one comes to mind immediately!)
How about powercats? I've watched their behavior while underway a few times and they seem to handle beam wave action much better than monohulls. While I was shopping for a runabout in the Keys I briefly looking into Glacier Bay and ProCat. Unanimous advice against them for hobbyhorsing at anchor and low speed turned us away from them. The trawler versions seem to have a higher length to beam ratio on the individual hulls, but I've yet to chat up an owner who uses one

This is ending up in an interesting discussion gentleman.

markpierce said:

Follow your gut, but aren't you facing an uphill battle?

Still, if you're drifting while fishing, I'll say again a wisely-employed sea anchor is worth pursuing. Wonder what you will do with ocean swells causing the boat to constantly rise and fall despite attempts to eliminate roll.

Click to expand...

Of course the boat moves, and its going to move out in the open ocean. We do not know each other, but the admrial and I have well over a decade of open ocean cruising experience. This isn't my first boat.

What I'm attempting to do is to make that experience more comfortable. If you think about it, the entire stabilizer industry is built around just that.

Aquabelle said:

NAIAD's new At Anchor system will work when drifting or anchored. Yes, you would need to have the genset running...but this is true of the gyro also when at anchor. Reportedly, roll damping by NAIAD underway is more effective than that of gyros.

Click to expand...

I enquired about that. The challenge is that would require a much larger generator. The Naiad at anchor system takes a steady 8KW of power. I have a brand new 8KW northern lights generator on my boat. I really do not want to spend an additional $15K on a new generator as part of this upgrade. It would not be an issue except that I just bought the new generator last winter, and it has all of 140 hours on it.

twiisted71 said:

Unless you have some innate bond to your boat, this could be an ideal time to seriously look at another boat you've been lusting after. Dropping $50K on a single system on a not new boat (I don't know the age/value of your boat), would go quite some distance to rationalizing a boat upgrade with some features you've found you'd really like to have (one comes to mind immediately!)
How about powercats? I've watched their behavior while underway a few times and they seem to handle beam wave action much better than monohulls. While I was shopping for a runabout in the Keys I briefly looking into Glacier Bay and ProCat. Unanimous advice against them for hobbyhorsing at anchor and low speed turned us away from them. The trawler versions seem to have a higher length to beam ratio on the individual hulls, but I've yet to chat up an owner who uses one

Click to expand...

I've had this particular boat one season. It is a 2001 Bayliner pilothouse 4788. This is the exact same boat as the Meridian 490 pilothouse. I had the boat in a shipyard last winter for a complete repwer and refit.

The boat is for all intent a brand new boat. Everything is new. Many of the systems have been upgraded to better than factory new. It is the platform I want to use for my coastal cruising. This is my retirement boat. I "built" this boat to be the perfect coastal cruiser. No compromises, no budget. This boat has everything (except stabilizers) that I could ever ask for in a coastal cruiser.

I almost put stabilizers on it last winter. I wanted to put a season under the hull first to assess how she did. When I learned about the gyros this spring it gave me a choice. Now is the time to make a final decision. Not IF to stabilize, but WHICH stabilizers, is my delemia.

Have you considered a flume tank? I pulled this off of a Boat Design thread. I haven't been on the T&T forum in some years but the owner of this boat used to post there & I remember him being very happy with the results under power & at anchor.

"One example of the Flume Tank that apparently works was designed by Professor Don Bass of St. John's Newfoundland. This tank was mounted on a motoryacht called Swan Song, a Roughwater 58' designed by Edwin Monk. The rectangular tank is on top of the pilothouse, and is 12' long (athwartships), 4' fore and aft, and 16" high. Inside are 5 T-shaped baffles !8" from either end. The tank reportedly weighs 250 pounds (foam-cored glass) and has 1550 pounds of water in it, about 6.5" deep when floating level. The owner it totally tickled with it. Zero maintenance, zero drag, but of course real concern about high-angle stability and a simple system to dump the weight if needed."

OK your innate bond has been established. If this is your lifetime boat you can pour all the money you want/can into it without worry of losing your shirt. This is JMHO. Those "this is the last xxxx I'm going to buy" things are disposable in my mind. I'm going to keep it till I die and I can't take it with me so I'm going to have and enjoy what I get. When I kick off I don't really care what happens with my xxxx. I'd do everything I could to experience a demo of the gyro system in action on a similarly sized boat. Try it underway and at anchor and turned on and off. That is a lot of coin to drop without a comparable demo. BUT if they live up to the hype they would be the #1 choice while anchored.
Another thing to consider (and I'm sure you have) is the fins while proven have a few possibilities that personally give me pause. 2 nice large doo-hickies to catch on ropes/reefs/flotsam/jetsam. Also if they go out what are the chances that they will be in a neutral position. They eat up a lot of real estate in the engine room and it seems they would require just as much reinforcement as the gyro.