Rolly Polly ????

I have a 36 ft Gulfstar trawler. Other than the beam sea induced roll we are happy with the vessel. Need to stop the roll. Any suggestions? I have tried the stay sail, questionable results. Don't think the sali is big enough. Next looking at "Bilge Keels". Documents on these keels is non-conclusive. I do believe the best results are on round bottom hulls as I have. Kristen Marine has use paravaines on their 25 ft Bojam trawler with excellent results. Any thoughts and suggestions would be appreciated.

Ken

You pretty much listed the solutions in order. Past those are active fins and gyro-stab.


Steadying sails do work in beam seas....the stronger the wind the smaller they can be. So if in a wind induced chop..you might see improvement with a normal sail...but most of the time or in swells different than the current wind induced...the sail has to be big...almost as much as what a sailboat would carry. For inland waters where the rough stuff is more wind induced than swell....just enlarging the sail is often the simplest.


Bilge keels help...but now are one step up on the design and expense ladder.


I just live with the roll and try to plan for conditions where it is tolerable...but then again for now and probably forever my longest open water passage will only be the Bahamas and maybe Cuba.

I have a boat that rolls easily too and I find changing course either helps or almost eliminates the roll. Just a few degrees change in course changes the timing of the waves passing under your boat. It's natural tendency to roll back and forth can be matched (bad rolling) or mismatched to achieve minimal roll. Experiment w the wakes of passing boats applying various angles of course crossing them and you'll find if you get it right practically no roll will happen. Of course if a course change is impractal as when you're in a narrow channel being passed by another boat ....
Most of the time that's not the case.

manyboats said:

I have a boat that rolls easily too and I find changing course either helps or almost eliminates the roll..

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As Eric has stated, "tacking" the boat is a great help. Just because you have a power boat, don't ignore the lessons of "sailors" who have gone hundreds of years before. And, as he has stated, it doesn't take much of a course change to smooth things out.

Codger2 said:

As Eric has stated, "tacking" the boat is a great help. Just because you have a power boat, don't ignore the lessons of "sailors" who have gone hundreds of years before. And, as he has stated, it doesn't take much of a course change to smooth things out.

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That's what we do no big deal . We've been caught in a trough before an it becomes a quick snappy roll and not sure what to do when that happens. I get the look like
"get us out of this " Anybody got suggestions ?

My steadying sail helps quite a bit in some situations, tacking too. Paravanes seem like too much rigging / trouble for me. The rolling doesn't bother me really anyway. Offshore, on AP, I'll tack before using the head or or making a meal the rest of the time I sit with my legs out, braced across the bridge seat, facing my "danger zone" and read. Good seaboats roll.

Kasten has a good article about anti rolling devices, http://www.kastenmarine.com/roll_attenuation.htm.

The only thing he seems to have missed was gyroscopes.

Bebee's book also discusses roll attenuation.

Later,
Dan
http://www.kastenmarine.com/roll_attenuation.htm

We over came the snap rolling on our Marben by adding 20 55# lead ingots to the bilge and either sides of the engine bed. We still roll but very softly. It also assisted with the "Hobby Horse" effect due to the short water line length of 27 feet. All points of the compass regarding motion were vastly improved.
Al

Be careful about arbitrarily adding ballast.


I believe I have read that just adding it to the center of the boat and low can actually worsen some already bad habits in some vessels.


Of course trial and error carefully done is something anyone can try.

My boat is very roll as well, even with the bilge keels. I'd hate to see how roll it is without them. Raising the sails almost completely eliminate the roll, IF there is 15+ knots of wind. The only time I have to put up with a bad roll, is after several day of strong winds, when the seas are still rough but the wind has died.

I have about 300 square feet of sail area. I don't know what a Gulfstar has, but I'd guess about half that.
A bigger mast would be needed to increase your sail area, but paravanes may be a cheaper option. I'd recommend either, rather than bilge keels.

Question here . Our boat originally was a commercial fishing boat with reel and it also has telltale signs of outriggers . The reel and outriggers or para vanes were removed . The fish hold has a generator ,not sure if that was original or not , but I guess something ran the hyd for the reel . I have about 400 gal fuel capacity and 150 gal water . I only keep about a fourth of fuel capacity on board and 1/2 the water because we only have time for short trips . If and when we get the time to really stretch our legs is toping everything off going to help at all with roll? Should I be considering adding ballast because the reel and outriggers are gone ?

The nice thing about a steadying sail is it doesn't need shape...just tight like a board.


So without increasing the mast height..there are different possibilities of increasing sail area such as gaffs or sprits.


A lot of work...but so are all the other alternatives.

Pack Mule,

Given having the tankage would keep the tanks on the full side. Let me explain. We added the 1100 # of aforementioned ballast of lead due to lack of tankage and the ensuing weight. Other models of our Marben came with 200 gallons of fuel and 100 gallons of water capacity. Our boat has 74 gallons of diesel and 48 gallons of water. You can see the vast difference in weight factor between two same boats. The comment regarding the care in location of ballast is actuate. As we located the lead in the same location of tankage of the larger capacity we believe we are in tune with the manufactures concept.
On top of this weight added, we recently exchanged the lighter weight engine Perkins 4-154 that is approximately 450# lighter than the replacement Perkins 4-236.

The removal of the commercial reel and plumbing has at a minimum 400/500#. Added to this is the lack of the additional fuel/water weight. contributes to adding top side weight effect. The removal of the rigging will add to the quickness of boat movement. Even with the gear in the upright position when it was installed, roll would have been reduced, When in the lowered position with the “fish” deployed the effect of rolling is reduced by a huge factor. Full fuel/water and reinstalling the commercial style para vanes would seem the easiest fix.
Al

Albin recomended putting ballast under the catwalk by the gunwale. Didn't do anything for right-ability I suppose but it's was known to dampen the snap part of a snap roll to a degree. Slow rolling is much less bothersome than quick roll response. The words "snap roll" was a very common expression among Albin owners. Heavy boats can have a snap roll too if quite flat on the bottom w hard Chines and beamy. Quite a few trawlers come to mind.

Holy cow Marty you've got too much tankage too. I've not had any water buildup from condensation but I keep checking.

Yes any weight added to the boat will help dampen roll. We have two tons of it inside the hull in the bottom of the keel. We sold the Albin and bought the Willard (weighing 4 times as much) and going from the Albin snap roll to the relatively slow roll of the Willard was a great relief. Many fishing boats in Alaska have roll rates so slow Willy's roll is a snap roll compared. Very seldom now do I holler "WAKE" to Chris so she can brace for rolling.

Beebe describes an anti-roll tank thing, I think water-filled IIRC. Might be the same as what Kasten mentions, but I seem to remember Beebe's book had some illustrations...


-Chris

Complete myth that "any weight added" will help dampen roll.


Placement is often way more important than "weight"....especially for those that keep telling us how weight is "bad".


In the wrong spots it can increase the amplitude or rate.


Putting weight out in the ends or beam might increase the amplitude a bit...but the momentum required to move it from wave action can slow the motion.


Think metronome among other things. That's why boats with paravanes will lower the riggers even if the fish aren't deployed because it slow the roll.


Be careful what you do and who you listen to...way to may partially educated experts....


Either it's a slow and careful trial and error...or someone has to run some numbers....


Rules of thumb are only as good as those who know what to apply and when.

psneeld said:

Complete myth that "any weight added" will help dampen roll.


Placement is often way more important than "weight"....especially for those that keep telling us how weight is "bad".


In the wrong spots it can increase the amplitude or rate.


Putting weight out in the ends or beam might increase the amplitude a bit...but the momentum required to move it from wave action can slow the motion.


Think metronome among other things. That's why boats with paravanes will lower the riggers even if the fish aren't deployed because it slow the roll.


Be careful what you do and who you listen to...way to may partially educated experts....


Either it's a slow and careful trial and error...or someone has to run some numbers....


Rules of thumb are only as good as those who know what to apply and when.

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What he said!

Marty since others have ignored your question I'll hazzard a guess. I say hazzard as psneeld will discredit it however he can.
Your boat should float "on her lines" I think is the expression and on your boat it's quite unlikely that that could be determined. If you knew the original displacement and could determine closely what the boat weighs now that would be a start. Basically the only thing left is to apply a CG fore and aft. How one would do that I don't know. Running the boat in challenging situations while being able to change the weight fore and aft so as to have good handling on following seas ect would be a very time consuming trial and error method that would work according to the skill and knowledge of those doing the experimenting. By asking a NA you would get a far better scope on how to do this but since you ask and nobody responded this is a rough guess. My own opinion only.
Having said that a simpler approach would be to distribute the weight in the boat somewhat evenly and perhaps favoring amidships and "see how she handles".

To dampen roll added weight should obviously be a considerable distance nice from CG. I thought that would be obvious.

manyboats said:

To dampen roll added weight should obviously be a considerable distance nice from CG. I thought that would be obvious.

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The whole point...... it is NOT THAT SIMPLE.....

Ocean-going Tug equipped with paravanes:

Op, I owned a 36 gulf star for 8 years and put a lot of miles under its keel. It's a good boat, but would roll the peanut butter out of the jar. We loved it anyway. Idon't believe there is cost effective solution considering the boat is worth $50, 000 or less.

If you plan open water travel trade up to a different boat. Seriously.

The snap-back roll is typical of a semi-planing hull with a fairly flat after-section and hard chines. This configuration does a good job of minimizing roll but only up to a point.

We dont mind the snap-back roll but from what I read a lot of people really hate it.

The effctiveness of steady sails seems to be very dependent on the type of boat. We contemplated having one made, not for roll dampening but for reducing hunting on a mooring or at anchor. We first talked to a number of owners of our brand of boat who had steady sails and the almost universal consensus was that they do a good job of reducing hunting while moored or anchored but are almost totally ineffective at reducing roll while underway in a beam sea. That's for this particular make; I have no idea how effective they are or aren't on other makes and configurations.

Another consideration that owners brought up was the risk that a steady sail could overpower the mast stay fasteners if the wind was strong enough. This, of course, is totally dependent on the strength of the mast's standing rigging setup. Our older boat has only two stays for the mast, and their anchoring system on the flying bridge, while sufficient for boom loads not to exceed 200 pounds, is not the strongest on the planet. Newer versions of the same model boat have four stays although I don't know if their anchoring system is any better.

In the end we decided not to bother with having a steady sail made and setting up the mast and boom with track and running rigging. The hunting issue on a mooring we deal with by deploying a Fortress off the stern which, with its light weight and effctive design, is a fairly quick and easy process.

If we had a boat with roll chacteristics we really didn't like, I think we would go for the passive paravane method of roll dampening if the boat could be properly set up for it. I have nothing against active stabilizers in terms of their effectiveness or ease of use. I simply have an inherent reluctance to make something like a boat any more complex than I think it needs to be to accomplish what we want it to accomplish. I'm not anti-technology, I'm anti-having-to-pay-to-fix-technology when it breaks. If somebody else is going to pay to fix it, well then, the sky's the limit, right?

Paravanes work , but have some expense , a learning curve and the downside of increased air height , more bridges will be come obstructions.

If the boat is sea kindly , the roll is slow ,esp when it changes direction , its not hard to live with .

A change of course of 5deg only puts you off 5 miles every 60 , and costs little .

With our Gulfstar 36 a course change or "tacking" made very little, if any, difference. The roll was uncomfortable, even dangerous in any sea over 2 feet in any direction except right on the nose (which it loved) or right aft. Anything on the beam or any quarter would cause a massive roll. Tacking just meant we were out there in open water rolling our guts out that much longer.

Dougcole said:

With our Gulfstar 36 a course change or "tacking" made very little, if any, difference. The roll was uncomfortable, even dangerous in any sea over 2 feet in any direction except right on the nose (which it loved) or right aft. Anything on the beam or any quarter would cause a massive roll. Tacking just meant we were out there in open water rolling our guts out that much longer.

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I agree that in many instances the amount of tack would either make the crossing time prohibitive or just makes the misery a tad less but much longer.

I will some time tack towards or head straight for a lee.....but those seem to be rare opportunities.

Most of the time I just wait out the worst days which for the last three round trips to FL via the ICW and Chesapeake have only been a handful...and I travel a lot in December and March...2 of the worst months for wind.

Adding ballast gets into static and dynamic stability as well as seakindliness. I think the concepts are sorta simple, the math IS simple but I don't find the subject to be obvious nor intuitive. Doing it wrong can be a very bad thing.

The best Internet write up on the subject that I know of is, again, Kasten, http://www.kastenmarine.com/beam_vs_ballast.htm. There is more to the link than beam vs ballast so don't let that title run one off. If one really wants to dig into the subject read C. A. Marchaj, "Seaworthiness: The Forgotten Factor"

Later,
Dan
http://www.kastenmarine.com/beam_vs_ballast.htm

Back to the Gulfstar. I tend to agree with Dougcole. His description of our gulfstar roll is extremely accurate. Of course the 2 ft beam sea is dificult only when the frequency is small, 4 sec etc. I seem to find that a 4 ft beam with 8 sec frequency is no problem. Now, I believe this is because of the round bottom. I also believe a semi displacment or planing hull would possibly be a problem in a large beam sea with large frequency since it would tend to float parrellel to the face of the sea. I do feal that tacking makes some difference but not much. I am told only 36 gulfstar 36 boats were made so consequently not much effort has been put into solving the problem. Now to the issue of finding another more appropriate vessel. Oh, and I also agree the idea of picking your days is smart no matter what the vessel, smart for many reasons and is a factor to good seamanship but, what those days, and there are many that change unpredictably and quickly? Back to another boat, what vessel? Even the out of price range "Passagemakers" have rolling issues and add sails, paravanes, gyros and tanks per Beebes book. Albin not a passage maker but looks good and still has some rolling. Willard, one mentioned in Beebes book added bildge keels with supposedly great results. Size is not a factor look at Kristens 25 ft passagemaker. Of course it has paravanes. Back to basic physics, a body at rest tends to remain at rest. This would tend to support ballest. But where is the cg of the vessel and righting moment and when is it exceeded. The roolig we are talking about is due to very poor initial stability. Although extremely uncomfortable it does not mean the vessel is dangerous. But until a righting moment is determined it would be foolish to assume the veesel has a fantastic righting moment. A gulfstar does not have a lot of weight located high of the deck. The flybridge is very small compared to most trawlers. I have also minimized as much high weight as possible. Ok, now assuming I decide it is time to look at another vessel which make and model? Trawler or do I become a sailor?

I also have a 36' Gulfstar trawler, bought her ten years ago. Travel mostly the Florida Gulf coast and the Keys. Regarding Rolly Polly, for me it is mostly how, when and where I drive the boat. I do believe in altering course if it gets too rough and since I am an ex sailor I am used to this. Tacking works for me. Also, I stay out of the ICW as much as possible because I dislike getting waked by other boats, which can cause much rolling. I don't boat on weekends either because this is when the crazies are out. I go offshore down the coast of Florida and to the Keys (and back) and I find this ride to be very pleasant, so maybe being in this part of the world also diminishes the rolling. Also, I watch the weather and only go when it is 'nice' out.

The 36' Gulfstar trawler is an inexpensive, coastal boat. If you shop you can buy them for less than $25,000 in decent enough shape such that you could use them immediately without a lot of additional expense. With this in mind I would never invest a lot of money in anti-roll devices.

But if I could not tack, and if I could not choose where and when to go boating, and if I REALLY wanted to seriously dampen roll, then I would pay attention to what has already been written and proven on this subject by [FONT=&quot]Bob Phillips, Another Asylum, Tortola, BVI, by Dave Cooper of Swan Song and by [/FONT][FONT=&quot][FONT=&quot]Professor Don Bass, at the Marine Institute in St. John, Newfoundland. This problem can be fairly easily and inexpensively solved without a lot of high dollar, add-on equipment. [FONT=&quot]The answer is ROLL TANKS.[/FONT][/FONT]
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