Stabilizing sail

Sail is about 65 sq ft. Send an email address and I can attach a pic; too stupid to do it here.
Roget

roger howell said:

... Most importantly, since we came from sail, it gives the crew something to do on long passages: hoist the sail, lower and furl the sail, cover the sail. ...

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Furling (rolling up, putting away) the Coot's mainsail (yet smaller than the jib):

roger howell said:

Sail is about 65 sq ft. Send an email address and I can attach a pic; too stupid to do it here.
Roget

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Try this:

http://www.trawlerforum.com/forums/s22/set-up-your-account-|-help-tips-etc-5739.html

Note: Post #6

here a pic from Roger (original sail w/o big roach and full battens)

Greetings,
WHAT??? No big roach? Well, we can't have that...

I tried the "right of way" ploy with my boating friends on several occasions whilst "sailing" but they OBVIOUSLY were unaware of COLREGS and replied with no end of insults and ribald comments...

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Sounds like they actually were quite aware and knowledgeable of the COLREGS!

Many years ago, when shopping that let us to "Retreat" we looked at a Californian 42 that came with a steadying sail. The seller was quite thrilled with it, as it had increased his spous's willingness to cross Georgia Strait from Blaine to the Gulf Islands. It must have made a difference on that boat. For me, what it did was to warn me away from the Californian as a potential purchase, since I didn't need a boat that was that rolly.
My own boat, with hard chiles, rolls in the right conditions, but a 10 to 15 degree course change will correct the roll. I get home a few minutes later, but cruise comfortably, with no need for all that extra gear and clutter.

The GB owners I have talked to who have steady sails on their boats have all said they accomplish pretty much nothing in terms of damping the roll in a beam sea but they do a great job at reducing yawing on a mooring or at anchor.

One problem, at least with GB's, is that their masts are not all that solidly stayed. So the thing to be careful of is overloading the stay hardware in a strong wind from abeam. But this is not an issue when the sail is keeping the boat headed into the wind on a mooring.

We've debated in the past about adding a steady sail to our boat to reduce the rolling moment in the boat when on a mooring but decided it wouldn't solve the problem we'd be trying to solve. What we want to deal with is what happens when the waves come from a different angle than the wind. This can happen in some of the long, narrow bays we moor in. The wind holds the boat at an angle to the waves so there is a rolling component to the boat's pitching in the waves. This corkscrewing motion can get rather tiring after awhile. A steady sail would simply exacerbate the situation.

So we use a stern anchor instead to hold the boat into the waves regardless of the wind direction.

For the purposes of keeping a boat headed into the wind on a mooring or at anchor the farther aft the sail is rigged the more effective it will be. I took this photo in Maine a number of years ag. A number of the lobsterboats on moorings in this bay had steady sails rigged in this manner.

All boat will roll in a big beam sea. A hard chined boat reduces the angle somewhat but increased the acceleration of movement. It's a matter of personal preference as to which is worse.
Sails will definitely reduce both the angle of roll and the acceleration of roll but, (as FF puts it) it takes more than a handkerchief.

For a sail to reduce roll the boat must be rolling already or else thee is no movement through the air to create resistance.
A strong beam wind of course will set up some heel to resist roll against the wind but what about in the opposite down wind direction?

rolling in waves is the result of the boats tendancy to remain perpendicular to the water surface. The wave makes that surface inclined so the boat also tilts.


A flat item such as a wide board will almost always remain flat to the water surface even if that surface is the face of a wave.


A partially filled beer bottle however will try to remain vertical as a wave passes.


Think of the flat bottom hard chine boat as the board that will try to follow the water surface and the beer bottle as the ballasted round chine hull that resists.


The greater mass of boats does however cause a resistance to following the surface but may also cause it to extend the roll. When the wave frequency becomes just right the boat may roll excessively.


To the OP, realize that being down close to the water will reduce the felt effect of rolling. About the only reason I would consider an inside helm

Personally the only thing I have experienced that really works is active stabilizers. I suppose paravanes work too.

To put things into a bit ofform of perspective my last sailing boat weighed 40 tons had 10 tons of lead in her keel 8' below the water which was designed to balance 3200 working square foot of sail area. My favorite sail size for windsurfing in 25 to 35 knots is about 55 sqft. Even though the sail has the power to launch me 15' in the air and is more efficiently designed than any steadying sail I can hold it vertical fully sheeted beam to the wind with only my body weight. The sail area of a sunfish or a laser is also about 75'. You could borrow one chock it up and strap it down to see for yourself if your so inclined.


Via iPhone.

bayview said:

The greater mass of boats does however cause a resistance to following the surface but may also cause it to extend the roll. When the wave frequency becomes just right the boat may roll excessively.

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Very true. A boat will have specific natural roll rhythm. If this is 2 second, odd number wave periods with have much less than even numbers wave periods. For example, a 3 foot beam wave every 7 seconds may cause less roll than a 2 foot beam wave every 6 seconds.

That's part of the reason why changing your angle only slightly when cruising in a beam sea can make the roll much better or worse. It changes the time interval between waves contacting your boat.

bayview said:

For a sail to reduce roll the boat must be rolling already or else thee is no movement through the air to create resistance.
A strong beam wind of course will set up some heel to resist roll against the wind but what about in the opposite down wind direction?

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there is movement, it is generated by the motor, if you're going 8kts the wind is almost that with no other breeze.

Down wind the apparent wind is less than any other point of sail.

So the wind needs to be a higher speed than that of the boat, so if powering at 8 with a true wind speed of 10 your apparent wind is only 2kts.

Apparent wind is what you feel.

Now down wind the sail will not stabilize the boat IMO

The most common case is the wind and swell roughly from the same direction. This works to your favour as when the swell in on your beam, the wind is as well.


In the occasional situation with swell on your beam while running downwind at wind speed +/-5 knots, I agree, - the sails won't be much help.

I find the most common occurrence of the sails not being of much use is the first calm day after a multi-day big blow. Zero wind and still a messy mixed up sea. It's better to wait one more day before setting out.

Here is a look at what a very small sail can do (or fail to do depending on ones outlook....) to reduce rolling in a heavy beam chop. The sail area is 75 square feet. The boat weighs about 15,000 pounds.

Wind was in the upper 20's with gusts in the low 30's. A few waves at the 1:00 minute mark in the video are an honest 4 feet, maybe a 5 footer snuck in there somewhere.

Most of the vessels owned by TF members are un-ballasted powercraft and therefore may not be as able to carry sail or tolerate rolling as well as this sail boat. However, Panope's keel is quite shallow (4' draft) and with somewhat deep bilges and narrow beam (9' at WL), she is quite tender initially and is probably less stable than many trawlers for the first 30 (or so) degrees of heel.

I did not shoot a "without sail" example but I can assure you that without the sail, rolling would have been terribly uncomfortable with perhaps double the angular excursions.

I believe roll reduction will be the primary benefit of a small sail on a trawler, however the 5+ knots of boat speed this little sail provided should not be discounted.

Steve

Wow. Great video. I have a boat with about 4000 lbs of ballast, 25000 LB displacement, 3'8" full keel, 35' LWL, and I have considered adding either a sail or paravanes. The roll reduction in your video with just the jib is impressive.

Here are a couple of videos of the roll on my boat in a much smaller sea state to compare.

Damn. Can't get videos to post.

Trying again...

https://click.email.vimeo.com/?qs=e...bd6c088b2bc0e1e0f41fcf9b8ae50b8810aa3f5d40c96

Cardude, I think your boat could be a good candidate for a stabilizing sail. If I were you, I would find an old daysail boat about 14 or 16 feet long and "borrow" the rig. Just lash everything temporarily (but firmly) and then go try it out. If you like it you will be armed with much better information when it comes time to do a permenant rig.

Like Panope, I see that your boat has a pilothouse that is quite far aft. For me this means that with a small headsail only, the boat is nicely balanced. If yours is also reasonably balanceable with a forward sail, then you have the option of using a roller furling jib that will make handling sail much easier.

Steve

Here is the factory configuration of my boat with the full sail plan.



I thought about doing this...



Paravanes and a jib.

Cardude, If you bring your boat to a stop with wind on the beam, does the wind blow the stern downwind? Bow downwind? Or does she lay broadside to the wind?

Steve

cardude01 said:

Here is the factory configuration of my boat with the full sail plan.

View attachment 46399

I thought about doing this...

View attachment 46400

Paravanes and a jib.

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I like the sketched rig waaaaaaaay better than the full factory sail rig.

Steve

full sail:

Panope said:

Cardude, If you bring your boat to a stop with wind on the beam, does the wind blow the stern downwind? Bow downwind? Or does she lay broadside to the wind?



Steve

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The bow blows downwind. Keel is full from bow to stern if that helps.

markpierce said:

full sail:

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Mark how tall is your mast?

Panope said:

I like the sketched rig waaaaaaaay better than the full factory sail rig.



Steve

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I think it looks better as well.

cardude01 said:

Mark how tall is your mast?

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Something in the order of 32 feet from the waterline. Maybe a couple of feet less. Can't remember if I included the antennae.

Cardude, every time I see this sketch of Tad's it puts a smile on my face.