'Flying Bird' Anti-Roll Stabilizers

[DefinitelyMe]

When we're on trade-wind passages we often find ourselves with the wind uncomfortably far aft for days or weeks on end, and we roll, roll, roll and roll some more. It fatigues the rig, knocks the wind out of the headsail so that it collapses and then fills with a bang and generally causes nerves to wear thin. Flopper - stoppers work at anchor, but what about underway? Fishing boats often tow anti-roll devices set out on booms to each side. Has anyone tried using one of these on a sailing yacht? Something like these things:

Trolling - Stabilizers - Kolstrand

And before some smart-arse mentions it - no, selling my boat and buying a catamaran is not an option 😀

[spearfish3]

Trawlers have used similar setups for passive stabilization, but I have never heard of it being used on a sailboat. You would need paravanes, which would have issues with the heel and the standing rigging would have to be substantially modified.

A more realistic approach would be a gyro stabilizer, but those need lots of power and it would probably still struggle with countering all the weight aloft.

Perhaps a Nordhavn, Diesel Duck or similar could work for you if a cat is out of the question? (Kidding)

[Jim Cate]

The drag generated by such devices is far too great to be acceptable in a sailing vessel.

We've found some help by running two headsails, one poled and one flying free, putting two reefs in the mainsail to flatten in and sheeting it amidships where it acts as a roll dampener. Not perfect, but noticeably better and reasonably fast.

Jim

[boatman61]

Never have the main up on a downwind personally.. and I'd rather do long tacks to keep the wind slightly off DDW..

[Paul L]

We setup on a broad reach. Get the waves in much more comfortable quarter, usually higher VMG, sails stay full. I'll give up rhumb line for comfort any day.

[DefinitelyMe]

Yes, drag was my main concern too. Deployment would be quite easy off the end of the boom, supported by a strong topping lift. Would the forces be that much more than those generated by a flopper stopper?

Our boat is a 1970's, genoa-driven design. The Genoa won't fill with the main up when lower than about 130 degrees apparent, so when we come up far enough to be able to broad reach under both sails our VMG is not conserved; passage times are vastly greater, especially in lighter air. Works better to take in the main and go deeper..... but then we roll. Boat also rolls much worse than most - often violently.

Sailing under main only is a little better but then the centre of effort is too far aft and reefing is much less convenient. Using the main as a damper is OK but I can't stand it banging back and forth with every roll and it wears the sail very very quickly, especially around the batten pockets. Which leaves few options. Simply putting up with it isn't really an option either - we have broken two stainless fittings on our lower shrouds in the last year (fittings 2 years old when the first one went) due to the fatigue imposed by the incessant rolling. Have a plan to redesign the rig to mitigate that, but it doesn't fix the cause of the problem and next year we'll spend 4 months at sea across the Indian Ocean and South Atlantic, so I'm keen for a solution.

Cheers for the input everyone. Much obliged.

[MartinR]

Originally Posted by Paul L

We setup on a broad reach. Get the waves in much more comfortable quarter, usually higher VMG, sails stay full. I'll give up rhumb line for comfort any day.

[DefinitelyMe]

So..... Back to the original question - has anyone actually tried one of these stabilisers? On a yacht or otherwise?

[boatman61]

To the best of my knowledge the type you are talking about are only used by fishing boats when trawling.. at speeds of around two or three knots and swung from strong purpose built swing arms..
The force induced by the higher speeds you will be wanting are going to wreck your boom.. and your topping lift to take the loads.. its not designed for this and not just viable.. to be safe you'd have to slow down and bang goes your desired mileage.. may as well do the downwind tacks.. or change your destinations.
What I don't get is the 4mths at sea.. is your boat that slow.?? or are you counting in time on the hook.. even at 800nm/week SA to Perth is 6 to 7 weeks nonstop at sea.
It does suck.. the rolling but.. that's downwind sailing in places like the S Pacific.. my crew had enough by the Marquesa's, managed to blag her to stay on but the next leg to Samoa did her in and she went home.

[skipmac]

I crewed on a delivery on a fishing trawler rigged with this kind of stabilizer. The booms and rigging to handle the loads were very substantial, far beyond what an existing sailboat rig could manage.

We did use the stabilizers at cruising speeds when things got nasty so they are functional at more than trawling speed but the loads really got serious at higher speeds.

[ZULU40]

theyre technically paravanes
used to used by mine sweepers

[NevisDog]

Just curious - what is the motion like on a multihull going downwind in the sort of conditions that drive us crazy on a mono?

[Cadence]

Originally Posted by DefinitelyMe

When we're on trade-wind passages we often find ourselves with the wind uncomfortably far aft for days or weeks on end, and we roll, roll, roll and roll some more. It fatigues the rig, knocks the wind out of the headsail so that it collapses and then fills with a bang and generally causes nerves to wear thin. Flopper - stoppers work at anchor, but what about underway? Fishing boats often tow anti-roll devices set out on booms to each side. Has anyone tried using one of these on a sailing yacht? Something like these things:

Trolling - Stabilizers - Kolstrand

And before some smart-arse mentions it - no, selling my boat and buying a catamaran is not an option 😀

Birds on fishing boats are flown of outriggers. I don't see that with a sailboat.

[RaymondR]

I often sail with twin poled out head sails and as you say the rolling is atrocious but since I day sail generally bearable.

I have pondered on the subject often, generally whilst either standing at the wheel and doing the heavy left foot, right foot exercise or hanging on for dear life, and inspiration has not yet struck.

However one of the things I have pondered is a very flat cut trisail with hollow leach and foot, hauled to the top of the mast in the main sail track with a traveling block arrangement up the back stay to tension the tack.

Other things I have dreamed up are flume tanks with electronic control of a flume gate or an eddy current controlled pendulum.

Since excessive rolling tends to be a resonance phenomena it might not require a great deal of dampening to achieve criticality. I notice that at times I can damp most of the roll out with proper timing of the left foot, right foot thing.

[Emouchet]

Switch boat if you cannot stand rolling. Go with a cat!