'Flying Bird' Anti-Roll Stabilizers

[NevisDog]

Originally Posted by senormechanico

Just bring those two extra bilge keels to the surface, make 'em float, extend 'em out sideways and you've GOT IT !

Something like this:

I'd love to, but last time I checked those two extra floating keels were expensive!

[DefinitelyMe]

Originally Posted by rosatte

Why don’t you fly a spinniker would solver your problem

Unfortunately flying a chute doesn't work either. On a reach with the main up too OK, but as soon as I go deeper than about 130, no go. Spinnaker just threatens to pull the rig out even more than the Genoa as it collapses and then fills with a bang on each roll. Tried all sorts of sail configurations and nothing does the trick except going in completely the wrong direction. We have two spinnakers on board - the small one is better than the big one but still a no-go at sea with any kind of swell. We have 3 different headsails. All the same problem. I'm pretty confident that the problem is the hull design. We've been in a lot of rolly anchorages over the last couple of years. Pitcairn, Marquesas and Niue stand out particularly. We sometimes have to sleep in our sea berths in the main cabin with the lee cloths up at anchor. Our boat is always the one with the most violent movement in any rolly anchorage.

At the moment we are tied up to a pile mooring up a river in New Zealand. The other day I unrolled the jib and set it in a light breeze in order to dry it before we took it down. Completely flat water. Boat not moving. Started rolling violently. One gust of wind lays her over just a couple of degrees and she starts up like a pendulum. I'm redesigning and re-building the lower shrouds to stop the stainless fittings from failing due to fatigue. I think we're just going to have to put up with it unfortunately........

[MartinR]

If you sail at 130 degree apparent and the boat is reasonably comfortable, why not do it? This translates to about 150 degree true and about 16% longer way to go. Speed should increase more than this. Even if the speed would be the same, the comfort may be worth the extra miles.

Boats with wide beam / high initial stability tend to roll more. A price to pay for the good interior space.

[NevisDog]

Originally Posted by DefinitelyMe

...One gust of wind lays her over just a couple of degrees and she starts up like a pendulum. I'm redesigning and re-building the lower shrouds to stop the stainless fittings from failing due to fatigue. I think we're just going to have to put up with it unfortunately........

Geeze, that sucks! Thanks for sharing that info, now I don't feel so bad about our slow progress due in part to our conservative, narrow beam. Even so, last time we changed course for a more pleasant ride we added nearly 12 hours to our short trip around North Cape; 45 degrees off course instead of 20 is a real drag.

(Also, the weight up the mast thing could be incredibly dangerous with so much initial 'form' stability, rather than mostly ballast stability.)

[Scout 30]

[QUOTE=redog;2564562]Scout 30
I didn't go into full design, but yes you are correct in your suggestions.
This would suit the type of boat in your avitar.
Torpedo front not required on fixed pole setup.
However triangle shape still desired as a smaller front section reduces rearward angle of vertical pole. Less drag.
Vertical rudder still keeps birds true in the water. Ones own preference here.

My vertical pole 12x50 flat Stainless with 2 off 40x40 angle stitch welded to flat bar. Way overkill but weight and available material not a problem to me.
I have seen many varied versions of round flat and square.
I have seen plough discs as birds with spinning pivot pins instead of universals.
Other suggestions on forum about chain birds are true. I have had a bird land on the sorting tray once, fix for this is to lengthen chains so they run deeper but once in shallows this becomes a major pain in the bum. You have to shorten chains again. Retrieving chained birds is harder also.

To retrieve bird I have sliding ring on pole with rope attached.
This ring locks up near universal whilst deployed, and with a simple flick of the rope falls to a lock on the bird.
Snatch on ring halves pull and I have a rope grabber mounted on the H frame that goes over the cabin.
I'm a couple of weeks away from the boat so photos will have to wait till mid Feb. I could sketch up a drawing if you intend to install a set.
Redog


Thanks for the offer. I've thought about adding a paravane system but it's not really period correct for a reproduction of a 20's motor cruiser. We typically deal with rolling by changing course but sometimes that's not feasible. Bilge keels would probably be the best idea for our boat but that's a big project.