Stabilzer sail on GB32

[ramkay]

Hello to all.
Does any of the GB32 owners out there can enlighten me on the size of the stabilizer sail, with drawings if possible, and the way it should be rigged for an optimal performance.

 

[psneeld]

My experience in forums about stabilizing sails is people with experience of 1 boat and one sail can be at either side of the spectrum. They do work of they don't work. Probably because many trawlers have masts more for looks than practicality.


My suggestion because most people are not familiar at all with stabilizing sails (they confuse them with riding sails or propulsion sails)....it to read up thoughts from designers who incorporate then seriously in the boat design.


Whether you go whole hog or accept partial use...your choice.


Here is one designer I have read and bought design books from...there are others...


Benford Design Group

 

[ramkay]

Thanks psneeld, will look it up. However, I'd like to use it under way in up to force 5 seas for limiting the rocking sideways especially when navigating at the flybridge helm.

 

[psneeld]

Thanks psneeld, will look it up. However, I'd like to use it under way in up to force 5 seas for limiting the rocking sideways especially when navigating at the flybridge helm.

One issue that isn't always addressed is beam seas when the wind has already shifted.


But with wind and seas on the beam and a right sized sail...they have been reported as "effective".


The quantitative data is shaky..... but good designers have done the math for that particular boat. So be careful when estimating what you need and how to adjust as conditions dictate.

 

[ramkay]

True, but what I understood is that a running rigging is applied that self compensates for the wind direction shift so you won't have to leave the helm while on way. I may be wrong.

 

[bayview]

Even with a direct beam wind your forward speed will make the apparent wind shift aft.

 

[psneeld]

A true stabilizing sail is really only designed and flown to be a flat surface to resist rolling...a wind off to the side is good but perfectly abeam is best. They are not designed for propulsion...yet propulsion sails do work as in sailboats...but they are not optimal for steadying in lighter winds as their draft just flogs the sail more.


Running rigging doesn't mean self adjusting, even self tending just means from tack to tack I believe.

 

[Xsbank]

The 32 has a very sharp chine which causes an uncomfortable righting moment in Beams seas or wake events. I had one. The size of a sail required to dampen that motion would be very large indeed. The equipped rigging and masts are not robust enough to support a sail of that size; consensus from GB owners at the old site was that hoisting a sail that would fit the rigging would be a waste of time. Many a time while rolling about we were driven off the roof because it was just too uncomfortable. The little GB was a terrific boat but too small for "real" stabilizers, however roll chocks were discussed...

 

[ramkay]

The reason why I'm asking about the sail size is that when I first purchased the boat, few years back and on the maiden voyage crossing the English Channel, we had the stabilizer sail, a triangular shaped one and a perfect fit on the mast, hauled all the way up. The rigging was somewhat tight and not quite a lot of play in it. At midway between Jersey and Guernsey, we encountered a freak wind storm jumping from force 3 to almost force 6 in a matter of less than an hour. It tore apart the sail before we even had time to adjust the rigging. So I wonder if there is a specific size sail and rigging method that would be the best fit or should we only use it while on anchor.

 

[Frosty]

I don't know if there were other factors, but old sails tear much more easily than new ones. The fabric gets frail for a number of reasons (UV, improper storage, original weight too light, stitching not maintained, owners allowing it to flog, etc.).

 

[Nomad Willy]

Those chines (mentioned above) generate large rolling forces. If you’re at a moment when a sea is applying forces in the same direction as the wind .. a lot of boats could get de-masted.

But under the same wind and weather a boat w less beam and soft chines would hardly have far lower forces on the rigging and steadying sail.

 

[AusCan]

Most sails on recreational trawler type boats are far too small to have a noticeable effect on stabilization. The sail area to effectively stabilize the hard-chined GB32 would be roughly 40-50 m3, along with much heavier mast and rigging than is provided on the original boats.
The mast and rigging on most or all of the taiwanese trawlers are mainly made for lifting the dinghy and for aesthetics.

 

[AusCan]

Those chines (mentioned above) generate large rolling forces. If you’re at a moment when a sea is applying forces in the same direction as the wind .. a lot of boats could get de-masted.

But under the same wind and weather a boat w less beam and soft chines would hardly have far lower forces on the rigging and steadying sail.

I agree, Eric. Soft chined boats roll far more (measured in degrees) than hard chined boats in similar seas, but any roll attenuation system is much more effective, and has less stress on the components. This applies to any type of stabilization system.

 

[JagShark]

Does anyone know the dimensions for the stabilizer sail for the GB-32? And the correct term for it; anti-roll? Stabilizer? What did American Marine call it in the 1970's? Lastly, I can have one custom made of course. But hoping to find the OEM data. : )

 

[psneeld]

It is a steadying Sail and the Grand Banks version was probably too small.

Jay Benford of Jay Benford design group wrote a nice piece on steadying sails and one of my fav designs of his was called Strumpet. The pic below shows what he would consider an adequate steadying sail...not the pathetic ones many Taiwan boats or Grand Banks came with.

 

[Caballero II]

Does anyone know the dimensions for the stabilizer sail for the GB-32? And the correct term for it; anti-roll? Stabilizer? What did American Marine call it in the 1970's? Lastly, I can have one custom made of course. But hoping to find the OEM data. : )

We've had this discussion many times on this forum. A GB of any size does not offer enough sail area square footage or rigging for a "Stabilizing Sail", period. What you can rig is a "Riding Sail", which clocks you into the wind. That is off some benefit, but is not a stabilizing sail.

 

[Mac G]

This is informative as we bought an older GB 42 that came with its original sail.
A riding sail makes sense.
For any other use the current spars do not seem properly rigged.
BTW - there is a comment above that the vessel's forward speed will send the apparent wind of a beam sea wind aft - it is the exact opposite actually.
More speed sends your apparent wind forward.
I am (was) also an iceboater too.
In an iceboat you have your main sheeted in tight as if you are beating on all points of sail when up to speed because you are moving so fast forward.

 

[Caballero II]

It is a steadying Sail and the Grand Banks version was probably too small.

Jay Benford of Jay Benford design group wrote a nice piece on steadying sails and one of my fav designs of his was called Strumpet. The pic below shows what he would consider an adequate steadying sail...not the pathetic ones many Taiwan boats or Grand Banks came with.

So, I take a little exception to this comment. The Grand Banks sail was never intended to be a steadying sail, but rather a riding sail, in the vein of riding sails used by some New England and NW Pacific fishing boats. Thus, not pathetic. And please don't confuse Grand Banks for a "Taiwan Trawler"

 

[psneeld]

So, I take a little exception to this comment. The Grand Banks sail was never intended to be a steadying sail, but rather a riding sail, in the vein of riding sails used by some New England and NW Pacific fishing boats. Thus, not pathetic. And please don't confuse Grand Banks for a "Taiwan Trawler"

It to me wasn't a riding sail...bad position for it and way oversized...unless they has a different one that those I have seen.

Do you have any documentation for it? Or a link that discusses it as a "riding sail"?

I know a Grand Banks and would never confuse the two..but if the sail on a Grand Banks was a sail that filled the area between the mast and boom like on most Grand Banks that I have seen (just like Taiwan steadying sails and the picture of a GB 36 below) then yes I call them pathetic and so have many others as they are grossly undersized and not tall enough.

From... https://www.denisonyachtsales.com/u...-banks-trawlers/42-grand-banks-boat-review-3/


"The boom for the steadying sail serves as a convenient davit for raising and lowering the dinghy to and from the deck."

 

[Caballero II]

So, yes Sneeld, it is a riding sail. Works perfectly nice to increase the windage abaft the COE. Not perfect, but fits what we've got, given raising and lowering a dinghy on that boom. Try one. You might like it. Definitely not pathetic.

 

[psneeld]

So, yes Sneeld, it is a riding sail. Works perfectly nice to increase the windage abaft the COE. Not perfect, but fits what we've got, given raising and lowering a dinghy on that boom. Try one. You might like it. Definitely not pathetic.

Never said it may not "help" as a riding sail would, so does standing aft in a good breeze.

I was thinking of one for my trawler but after the research, and finding how unsuitable my rig would be (similar to most production trawlers) and all the reports of poor performance I decided to go in a different direction.

But it is in a LOUSY location for a riding sail as shown below where they are most effective and on most trawlers it is too small and low to be a good steadying sail. It's more of a marketing tool, and it's mainly used as a dinghy lift for most owners... it's position is best suited for looks and convenience.

At best it is a "compromise" sail if it's gotta have a name. By mere function they are different sails. One for "riding" at anchor or mooring and the other for "steadying" the boat while underway. One sail can do both but neither well....just "help" a bit.

I let the crowd decide, hopefully some info will help the OP design his as without changing the mast/rigging it at best most have said not worth the effort. Best I would recommend a small triangular sail in the aft portion of the triangle just above the boom acting as riding sail. No need for a larger, more difficult sail to rig up as many trawler owners report them as "more trouble than they are worth as "steadying" sails.

 

[Mike GB32]

So ramkay- are you still following this thread after nearly 3 years?
I'm interested, did you find that the sail made a difference in a beam sea or maybe at anchor? Lots of theory in the above posts, I'm wondering about first hand experience on a '32.

 

[psneeld]

So ramkay- are you still following this thread after nearly 3 years?
I'm interested, did you find that the sail made a difference in a beam sea or maybe at anchor? Lots of theory in the above posts, I'm wondering about first hand experience on a '32.

Not sure he is...but JagShark resurrected the thread a couple weeks back with post 14.