Steady Sails...Do they work?

[Portuguese]

Greetings:

Per design, my boat is equipped with a 10.30 meters tall mast. The designer says that the boat will not sail with sails only and he put the mast*to*use steady sail. My question is, Does steady sails really reduce roll? How big of a sail do I need in a 25 ton boat?

I could use a mast to rig up antennas and have a boom as lifting equipment. At same time, a sail could be used as roll reducing equipment. Yet, do*I need such a tall mast for that?

Thanks

Fernando

 

[markpierce]

Yes, steadying sails can reduce the amount of roll if there is sufficient sail area and some wind.* Need more sail than the typical "handkerchief," but one certainly doesn't need the sail area or a tall mast of a sailboat.*

The fore-and-aft (jib and main) sail rig on my boat works well.* Two sails provide more sail area for a given mast height, and*moves the center of force closer to the middle of the boat.* The sails**increase stability, and with the right winds, can increase speed slightly but which can significantly reduce fuel consumption.

Regardless,*I'm not a nautical engineer and am unqualified to answer as to the necessary height of the mast.


-- Edited by markpierce on Thursday 21st of July 2011 09:46:02 PM

 

[Moonstruck]

How does*a small sail work to keep a boat from swinging too much at anchor?

 

[markpierce]

Haven't tried that, yet.* My builder says the trick is to have the sail (main sail in my case) set at an angle*rather than parallel/in-line with the keel.

 

[Marin]

Most people I've talked or corresponded with who have steady sails on their Grand Banks say they are pretty effective at reducing yaw at anchor or on a mooring and pretty much worthless for reducing roll in a beam sea. One thing a lot of people apparently don't take into account is how much strain can be put on a mast and stays if the sail is used to attempt to reduce roll. "Trawler" masts and booms are typically*not stepped or stayed like a sailboat mast, and I've read a few accounts on the GB owners forum about masts that have been snapped off by the wind and rolling action in a beam sea.

For reducing yaw on a mooring a steady sail can be quite effective if the sail is far enough aft of the boat's center of yaw. It's a bit like putting bigger feathers on the back of an arrow.* For this application the sail should be sheeted down tight*parallel to the*centerline of the boat. *I saw a number of lobsterboats in Maine the other year with rigs like the one in my photo. They keep the boats headed into the weather and waves but can be quickly taken down and stowed out of the way.

We don't have a steady sail on our GB although I have no doubt it would work to reduce yaw at anchor or on a buoy.* So we use a stern anchor instead.


-- Edited by Marin on Thursday 21st of July 2011 10:48:48 PM

 

[Tidahapah]

I have a few friends with sail assisted power boats.
Mainly use them as motor / sailors but a couple will sail under canvas alone with a decent breeze.
I have attached a couple of photos and the first boat a very similar design to my own and built by the same builder does sail quite well.
These boats are all full disoplacement cruisers with good draft.

With my own boat when I built her I put in chain plates and a compression post for later fitting of a mast.

Have never got around to it.

Boat is 48'6" 5'8" draft and weighs 28 tonne.

I was going to fit a mast approx 40 to 45 ft high with jib and main.


-- Edited by Tidahapah on Thursday 21st of July 2011 11:05:22 PM

 

[dougd1]

The steady sail (about 50 sq.ft.) does not eliminate or even reduce roll on Boomarang.* It does dampen the roll.* It is less "snappy" and makes the ride more comfortable.

At anchor, I find the sail useless.* It seems to cause the boat to want to "sail" back and forth, actually making it move around a lot more than if it is not deployed.

 

[dougd1]

Marin wrote:
For reducing yaw on a mooring a steady sail can be quite effective if the sail is far enough aft of the boat's center of yaw. It's a bit like putting bigger feathers on the back of an arrow.* For this application the sail should be sheeted down tight*parallel to the*centerline of the boat. *I saw a number of lobsterboats in Maine the other year with rigs like the one in my photo. They keep the boats headed into the weather and waves but can be quickly taken down and stowed out of the way.

* * * * * * * * * * * * * * * * * * * * * * * * * * ^^^^What he said.^^^^

 

[bshanafelt]

my sail is around 30 sq ft. and works somewhat for roll attenuation.* Probably along the description above of 'dampening'.

*

It is indispensable in a windy anchorage as it reduces the sailing at anchor drastically.* Without the sail up, the boat will wander somewhere around 50 degrees, which often will put us in an uncomfortable beam to wave scenario at each end of the arc.

With the sail up, the arc reduces to 20 degrees or so and is quite nice.

*

Just have to remember to take it down before pulling into a marina, or else I experience what it must be like to drive a tall flybridge enclosed single without a bowthruster.

 

[Phil Fill]

Being you boat is being mfg by mainly a sail boat builder, semi displacement the sail might be needed for the design to dampen the roll, just like the mast on a sail boat with out the sails. A de mast has a very snappy roll with out the mast.* As for the size of the sail that depends on the actual intended use.* We have a steady sail for our 20 ft mast with a 14 ft boom, which has little effect on the roll, so we do not use it.* Plus the mast, boom and stays are not strong enough to be used in a strong wind.***However, at anchor is does keep the boat from swinging as much.* If the mast was back to ward the stern more it would be a better vane. ***
*
So I would ask the builder the real intent of the mast and sails as it might be part of the over all design.**
*

 

[Tony B]

I used a steadying sail a while back when I had my Catalina 30 sailboat.

It was relatively small. Probably no more than 25 Sq. Ft. It was actually hung from the backstay and the front came down to a point (the tack). It was tacked down to a cleat on either the port or starboard side depending on which slight angle wored better for you depending on the wind. When set up it looked like a white weather vane on the stern of the boat. It worked really well.
It is a flat cut piece. If you use an old sail which has a belly shaped into it, it will have a tendency to sail up toward the anchor and then drop off again - all night long.

 

[tadhana]

Being an old New Englander where steadying sails were most common, I have seen steadying sails work to limit the roll and reduce the snap, but they do not work nearly as well as stabilizers. When I was a designer/builder I built a 37 foot lobster boat yacht for a customer who specified a steadying sail. the mast was about 20 feet tall and the rig was engineered to take the loads imposed just like a sailboat mast. The sail was about 70 sq.ft. Although we set the sail to prove the system on builders trials, and the owner set the sail for some photo ops, I do not believe the rig was ever really used.

 

[MurrayM]

Bump...

Things got really jumpy yesterday in Douglas Channel with 30 knot winds (lots of rock walls rebounding waves in several directions at once) so we bailed around noon before it got too bad.

We tucked into the back corner of Miskatla Inlet but it was still subject to some pretty strong gusts, so I rigged a budget steady sail at the end of the boom from a small tarp, and it worked like a hot-damn!

Most anchorages are more protected, so this is the first time anchoring in such a stiff wind. Will definitely rig up a Klemheist knot bridle for next time to reduce potential chafe at the anchor roller.

Just had to mention this because even such a small steady sail made a HUGE difference to the nylon rode yo-yo effect by reducing the bounce back and not allowing us to go almost abeam to the wind.

 

[cardude01]

Wow. Thanks for that. I'm surprised that small sail did much but the proof is in the pudding!

 

[MurrayM]

Wow. Thanks for that. I'm surprised that small sail did much but the proof is in the pudding!

Might be because our boom goes almost to the stern (use it for hoisting the dinghy onto modified Weaver Davits with a boat trailer winch) so that would maximize its effect. Here's a photo showing the booms length without the steady sail/tarp;

 

[psneeld]

Steadying sails are more for rolling...sails for keeping a vessel into the wind are often referred to as riding sails....

Riding sails just have to move the center of effort aft enough like feathers on an arrow....for rolling the sail would have to be much larger.

 

[MurrayM]

Riding sail it is then

 

[cardude01]

Yeah long boom.

I'm wondering how well these steadying sails will steady this boat.

 

[Tad Roberts]

I'm wondering how well these steadying sails will steady this boat.

View attachment 52311

Not particularly well most of the time. In 25 knots of wind directly on the beam they will sort of work. But a steady sail works better with boats that are initially less stable. The DD is a pretty stiff boat, they're heavy vee bottoms that like to follow the face of a wave. It takes lots of force to counter that tendency. With the sails up a lighter weight, round-bottomed hull with less initial stability will heel a bit and just stay there.

 

[cardude01]

Not particularly well most of the time. In 25 knots of wind directly on the beam they will sort of work. But a steady sail works better with boats that are initially less stable. The DD is a pretty stiff boat, they're heavy vee bottoms that like to follow the face of a wave. It takes lots of force to counter that tendency. With the sails up a lighter weight, round-bottomed hull with less initial stability will heel a bit and just stay there.

Like my hull I guess...

 

[markpierce]

They help. You would be a gullible to believe that it eliminates most of it. Teeny, tiny sails won't do it. (Pictured here making a 360-degree maneuver for FlyWright's photo taking.)



Who needs a boom? A traveler between twin back stays works.