Steadying sail design/rigging?

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LeoKa

Guru
Joined
Apr 15, 2017
Messages
1,246
Location
USA
Vessel Name
Ironsides
Vessel Make
54' Bruce Roberts steel sailboat hull, coastal LRC, 220HP CAT 3306.
I have a mast and a boom on top. I use it to haul things up and down, when needed. It looks very strong and long enough to put up a steadying sail somehow.
My boat is very tender and rolls quite a bit. I am thinking to setup a steadying sail to reduce the roll. This is not for anchorage roll, but rather cruising roll while underway.
I know there is no perfect solution, but it does not hurt to try, since it is not very expensive. I do not know anything about sails, or how to setup and handle sails. I am not looking for anything special (riding sail would be nice for emergency get home solution, but I think that should be a separate sail). The boom and mast has already plates welded on, where I could drill some holes for the rigging. It is aluminum and looks strong. I can swing the boom out for about 50-60 degrees in either direction, if that is useful for this purpose.
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Anyone has done it alone, or it has to be ordered and manufactured? I took few photos of the mast/boom, so you can advice me what fits, or not?
Thanks.
 
Your mast is rather short for using with a steadying sail. Don't expect much thrust.
A local sailmaker or marine 'recycling' (used goods) store might have used sails
that can be recut to fit that geometry. Used sailboat hardware like sail track, cars
and sheaves can be found to keep your costs reasonable. The rig you have looks
pretty stout and should be able to handle the loading from any sail that will fit it.
 
Thank you. I was not expecting perfection. Since the cost can be kept reasonable, it worth to play with it.
Perhaps a longer boom can be mounted, but that would increase the weight on the top. That would not help.
I'll look around in the area for sources.
 
What Knot and Leo said. For steadying you will be "sheeted in" tight most of the time, which means boom almost centerline and sail flat and parallel to the keel.
For what you are trying to do I would set the sail "flying," that is no track on the mast, just haul it up on a halyard , attach the tack near the gooseneck, and attach the clew to the back of the boom tight.
Visit a local sailmaker with dimensions, leave a ft or so off all for blocks and lines, and tell him what you want, a cut down used main with a wire sewn into the luff should serve you fine. Here's a thread from the past.

 
Steadying sails are in my opinion one of the least understood topics on TF.

Many have no idea that steadying sails, riding sails and propulsion sails all have specific duties and are designed and placed differently.

Jay Benford the yacht designer has done some writings on steadying sails that I have studied....find some of his writings if you can.

I my experience and research...they should be designed to be flat, hard cloth, sheeted and trimmed in hard and flat, as tall or high as possible. They are designed to act like a sheet of plywood that counteract roll with air resistance. It is more akin to a storm trysail with very little draught. If made from a used sail, ensure it is heavy cloth and the draught is removed.

Search TF for past threads and understand that steadying sails need to be much larger than what many "trawlers" have in the was of mast/boom setups....and these threads are full of what I think is questionable info.
 
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A gaff rig would put more sail aloft, I wonder if anyone has tried it.
 
i have a sailboat 44 ft roundbelly with 18 m mast and a 40 sqm main sail. with no wind and chop or old swell its rolling heavily with or without the sail up. normaly i took it done to avoid flapping of the sail. if there is wind of course no roll at all. often i wish i had stabilizer when sailing or motoring downwind with old swell.....as written if you do make it strong and hard so no flapping at all.
 
Visit a local sailmaker with dimensions, leave a ft or so off all for blocks and lines, and tell him what you want, a cut down used main with a wire sewn into the luff should serve you fine. Here's a thread from the past.

- I have read that threat before. I have learned the basics from it.
- It seems this is not a job I can do. I will find a sailmaker in my area.
 
I my experience and research...they should be designed to be flat, hard cloth, sheeted and trimmed in hard and flat, as tall or high as possible. They are designed to act like a sheet of plywood that counteract roll with air resistance. It is more akin to a storm trysail with very little draught. If made from a used sail, ensure it is heavy cloth and the draught is removed.
- Good description and this is all I want. Only a ' steading sail '. I do not have high expectations, but I want to try it. I know my boat is not designed for it, although, the hull is a sailboat hull with 7.4' draft.
 
if there is wind of course no roll at all. often i wish i had stabilizer when sailing or motoring downwind with old swell.....as written if you do make it strong and hard so no flapping at all.

This is what I am hoping for; with wind underway, some reduction of roll. I suspect a sailmaker business would know the difference between steadying and riding sail.
 
What is a gaff rig?
A gaff rig has a four cornered sail. There’s a conventional boom and an upper boom called a gaff. The aft end of the gaff is pretty high, in fact higher than the top of the mast. This puts more sail aloft than a triangle shaped sail.
Its only a passing thought, not sure if it’s been tried before.
 
A gaff rig has a four cornered sail. There’s a conventional boom and an upper boom called a gaff. The aft end of the gaff is pretty high, in fact higher than the top of the mast. This puts more sail aloft than a triangle shaped sail.
Its only a passing thought, not sure if it’s been tried before.
That will not work for me. I try to limit the weight on the top. I am sure it works on other designs.
 
I'd wonder if the result would be worth he effort. Using a sail to reduce roll under way only works in some conditions, likely a minority of conditions. It has to be windy enough that your boatspeed doesn't just bring the apparent wind angle so far forward that it becomes ineffective, and that's if you're not already motoring into the wind. Also it isn't a very tall mast, so not much sail area. So, ya, maybe if it's blowing 20+kts on your beam or aft it might have some effect.
 
I'd wonder if the result would be worth he effort. Using a sail to reduce roll under way only works in some conditions, likely a minority of conditions. It has to be windy enough that your boatspeed doesn't just bring the apparent wind angle so far forward that it becomes ineffective, and that's if you're not already motoring into the wind. Also it isn't a very tall mast, so not much sail area. So, ya, maybe if it's blowing 20+kts on your beam or aft it might have some effect.
I am sure you are correct. My speed is 6 knots. I do not have high expectations, but if it works sometimes, due to the inexpensive nature of this installation, maybe I will give it a try.
The sail does not need to be pushing the boat. Just hold it a bit, when it is possible.

I wonder, if there are members here, who actually had a steadying sail added and what their experiences were?
 
I'd wonder if the result would be worth he effort. Using a sail to reduce roll under way only works in some conditions, likely a minority of conditions. It has to be windy enough that your boatspeed doesn't just bring the apparent wind angle so far forward that it becomes ineffective, and that's if you're not already motoring into the wind. Also it isn't a very tall mast, so not much sail area. So, ya, maybe if it's blowing 20+kts on your beam or aft it might have some effect.
I am sure you are correct. My speed is 6 knots. I do not have high expectations, but if it works sometimes, due to the inexpensive nature of this installation, maybe I will give it a try.
The sail does not need to be pushing the boat. Just hold it a bit, when it is possible.

I wonder, if there are members here, who actually had a steadying sail added and what their experiences were?
 
If I had to vote on this with my wallet I'd do a test with a silver tarp. 11 ft. 4 in. x 15 ft. 6 in. Heavy Duty Reflective All-Purpose Weather-Resistant Tarp

Cut the tarp to the shape of your rig. You don't need to get too fancy with clew and head of the sail. Just knot up those ends and lash them with some line. Go cruise in the common roll scenario you generally encounter and see if it makes a difference once you raise the sail. Even if it blows out after a 1/2 mile that should give you enough information to know if it made a difference or not. I don't think you can go too wrong doing a $20 test with a tarp and it's something you should be able to do quickly.
 
Steadying sails are not the same as propulsion sails. They are flat and actually work just fine in dead air. Apparent wind is not part of the equation. If there is crosswind and it causes a heeling moment... great... the bad news is it usually causes some leeway which is usually undesirable, but a little leeway is a small price to pay if roll is abated somewhat in uncomfortable conditions.

As for most steadying sails..... they are too small due to mast height. They may have some effect but most trawler owners report they are more trouble than worth, but that is probably due to a poor design.
 
As for most steadying sails..... they are too small due to mast height. They may have some effect but most trawler owners report they are more trouble than worth, but that is probably due to a poor design.
Good points. Thank you. It seems that this will be a multiple stage creation.
 
Photo of what we put on our last boat here
Mâture - Trawler long-cours
The mast is a 9kg per m, the length was 8 m, stand up with 7 cable : one fore, 2 each side on the roof, 2 aft.
It was for a boat 32T , beam 5 m, draft 1.3m, lead ballast 2.3T
The main sail was ( memory ?) 17m2 full batten
Capture.JPG
 
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hahaha, I think you are having a good idea here, I might just do this test....
Tyvek building wrap makes a good sail as well. Have to install your own grommets though.
 
Photo of what we put on our last boat here
Mâture - Trawler long-cours
The mast is a 9kg per m, the length was 8 m, stand up with 7 cable : one fore, 2 each side on the roof, 2 aft.
It was for a boat 32T , beam 5 m, draft 1.3m, lead ballast 2.3T
The main sail was ( memory ?) 17m2 full batten


Looks good. Who made the sail?
 
Tyvek building wrap makes a good sail as well. Have to install your own grommets though.
I can do the grommets. You are correct, this could be a good test to see, if it works?
 
Looks good. Who made the sail?
The main sail was made by Lee Sail Hong Kong
the jib was made long time ago, may be 45 year ! by French sail maker Tonnerre but unused since we fit it on our Long-Cours 62.
with only the jib by 15 kts on the side we can reach the amazing :) speed of ... + 3 kts
 
In my mind a steading sail may be of use when travelling 90* to the wind. Except offshore how often do you intentionally travel sideways to the wind and waves. Once you are in the seas where it is needed deploying will be hell, so you must have it set beforehand.
Recently, I tacked to my destination zig-zagging to avoid a direct line and always sideways to the waves and wind.
There is a reason why boats capable of a steady sail do not use them.
 
with only the jib by 15 kts on the side we can reach the amazing :) speed of ... + 3 kts
I see. So the purpose of your sail were propulsion, not steadying?
 
Recently, I tacked to my destination zig-zagging to avoid a direct line and always sideways to the waves and wind.
There is a reason why boats capable of a steady sail do not use them.
Good point. I had to zigzag myself last June coming down the WA coast.
Deploying a simple sail might not be too difficult, but I take your word for it. I have no experience with sails.
 
This is ours in use. If you are anywhere in the Puget Sound area, the Sailboat Wrecking Yard in Lynden, WA is a great source for used sails.
 

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