WishBone Sailing Rig

brian eiland · Oct 19, 2015

Capsize Prevention

I would suggest that these discussions of sheet release mechanisms be moved over to a more relevant subject thread I introduced a few years ago:

http://www.boatdesign.net/forums/multihulls/capsize-prevention-devices-41340.html

Angélique · Oct 19, 2015

brian eiland said: ↑

I would suggest that these discussions of sheet release mechanisms be moved over to a more relevant subject thread I introduced a few years ago:

http://www.boatdesign.net/forums/multihulls/capsize-prevention-devices-41340.html
Click to expand...

Done ! - Further responces to the Multihull Capsize Prevention Devices please there . . . :idea:

RHP · Oct 22, 2015

To get back on track with A Frame rigs, Frank MacLear designed some beautiful rigs back in the early 70' but of course didn't have the advanced rig materials, lightweight sail materials, advanced roller reefing technology or IT programmes that we enjoy today. Just imagine ARIA a Palmer Johnson 87' yacht with an A Frame. Despite being built in 1975, (40 years ago!) she had 14 electric engines running the furling systems and primary winches enabling her (as much as possible) to be sailed by a couple.

Frank MacLear was years ahead of his time.

brian eiland · Oct 23, 2015

Thanks for posting those photos RHP.

Don't know what real benefit those rigs would have with an wishbone mast over their existing configurations?

But I can see what he (and the others) were striving for with that bigger headsail and boomless/roller furling mainsail configuration,...simplicity and single-handed capabilities.

Perhaps with their more aft placed mast (central), and emphasis on the roller furling aspect they belong in the aft-mast discussion (I'll place a link there)

Regards, Brian

Spiv · Oct 23, 2015

RHP said: ↑

To get back on track with A Frame rigs, ......

Frank MacLear was years ahead of his time.
Click to expand...

Hello RPH, was the first one an "A" frame?

I put a link to your post on my thread http://www.boatdesign.net/forums/multihulls/main-less-rig-21274-4.html#post755071

upchurchmr · Oct 24, 2015

Nice pictures, but none of them are an A-frame.

Were you getting back to A-frames or was it I "wish" it was a wish bone rig?

CT249 · Oct 24, 2015

RHP said: ↑

To get back on track with A Frame rigs, Frank MacLear designed some beautiful rigs back in the early 70' but of course didn't have the advanced rig materials, lightweight sail materials, advanced roller reefing technology or IT programmes that we enjoy today. Just imagine ARIA a Palmer Johnson 87' yacht with an A Frame. Despite being built in 1975, (40 years ago!) she had 14 electric engines running the furling systems and primary winches enabling her (as much as possible) to be sailed by a couple.

Frank MacLear was years ahead of his time.
Click to expand...

Have we got any objective, independent evidence that these rigs actually worked particularly well?

brian eiland · Jan 27, 2016

High Tacker said: ↑

Hello upchurchmr,

Apparently you are interested in trying an A-frame rig or something similar on your Tornado 20 cat? Daysailing, you say, still high performance, but maybe something safer, easier to handle, more like a cruiser?

If you already have the gear, the beam, etc., for carrying a jib at the center between the bows, probably cheapest and easiest would be an A-frame with just a jib and a mainsail on the centerline, both on furlers, no booms, like the SMG 50 mentioned several times in this thread,

http://www.sail-the-difference.com/..._of_the_easy_to_use_smg_catamaran/smg_50plus/

and Gary Hoyt's Manta Clipper is very similar (see first 2 photos below) although it has a boom on the mainsail.

Or, if you want to play around with a lot of different sail configurations, check out my Catbird Suite at

www.damsl.com

But I would suggest the PYRAMID RIG

It might LOOK more complicated, but another rig that I've experimented with is what I call the Pyramid Rig. It amounts to 3 windsurfer rigs pinned together at the top to form a 3-legged pyramid. All 3 masts rotate 360 degrees. Wishbone booms maintain sail shape on all points of sail. If you get in trouble, you just let the sheets go, and everything weathercocks. You can leave her sitting on the beach with all sails up, or at a dock or a jetty or tethered behind your big boat.

Construction is easy. 3 aluminum tubes of 1 inch circular section, attached to the boat, on hinges if you like so that the rig can be lowered easily, and a bolt at the top through the 3 tube ends all in a row with the jib tube in the middle between the 2 side mast tubes. Every couple of feet along these tubes there is a plastic bushing-type of bearing made of the same kind of stuff that you make prop shaft stern tubes of. These tubes are inner masts and then there is an outer sleeve for each of them and the outer sleeves are 2-inch luff spar sections that slide on over the plastic bearings. So then you have rotating masts which are very strong and can take a lot of bending from the wishbone booms and still rotate around those plastic bearings. The booms are hinged onto pins on the outer mast sleeves.

See the photos below. That tiny jib was ridiculous and I later got a big jib that filled up the foretriangle between the jib mast and the two side masts. I had the little jib made before deciding to go with 1 jib mast in the center instead of 2 jib masts, 1 to each bow. That would have made a 4-legged pyramid. This little cat was actually built as a powercat meant to be driven by an outboard or two, and so it's narrow in comparison to sailing cats, hence a small jib if it had to swing between 2 masts at the bows.

I don't have photos of the big jib, but it was made of dacron. The plastic sails were on the advice of the sailmaker, because a lot of windsurfers had plastic sails. But that was a mistake and I much prefer cloth sails for a number of reasons, not the least of which is that stupid birds will accidentally collide, beak first of course, with see-through sails. Who wants leaky sails?! And they are a pain in the *** to hoist up the groove of the luff spar and to take down, because they have to be rolled up, not folded at all. Dacron will take a lot of punishment.

If I did this rig again, I think I would go with the 4-legged version on a beamier cat, but shouldn't get too long-winded about that here.

You can imagine the advantages of such a rig. You can make it as tall as you want for performance. Yes, there is of course a weight consideration, although I think it could be built of much smaller and thus lighter sections than what I used. I don't think it would be all that much heavier than the conventional rig on a Tornado. And the weight is balanced by the smaller, or re-directed, heeling moment that you get from slanted sails in such a biplane rig, that is, the 2 side masts form a biplane, one side of which is pushing the windward hull down, and the other side is lifting the leeward hull. And since the sails can rotate, you just let them go when heeling gets critical, and they just weathercock. With the wishbone booms, they don't flog like with a conventional boom.

It's very safe downwind, because you let the sails rotate beyond 90 degrees to the wind, so that they are always taking the wind on the proper leading edges and there is no danger of jibing. And do you have trouble reefing your big conventional main downwind, or getting it down? This rig eliminates all that bother. You just let the sheet go, and the sail weathercocks and there's no shrouds in the way.

Anyhow, have a look at the pics below. Note that in some, I was experimenting by using one of the mainsails as a bigger jib, before I got a big cloth jib, and in that makeshift arrangement, the forward end of the boom, where it is attached to the mast, was not high enough, hence the sail shape is not right. Also, the cloth jib was much bigger, its boom much longer.

Note that when the little cat was tethered behind the big cat, with no wind, all the sails fall toward the center, but when the wind got up, they would just weather cock. So I just detached the sheets and left her with sails up. As I said, the plastic sails were a pain in the *** to get on and off.

I sometimes wish I'd done this rig on Catbird Suite, but it would have been much more expensive than the A-frame, because I would have wanted to do it of carbon fiber. Also, the A-frame leaves lots of room for experimentation.

Note that this pyramid rig is very strong. There is very little compression on those masts. And, unlike the vertical bipole rigs on a few cats, which do not have the masts connected at the top, there is no big complication of strength and rotating gear at the base in the pyramid rig, because there is no big bending load at the base, indeed, the masts can be mounted on simple hinges for lowering. Note, too, that there is no great tension involved either, as in conventional rigs, so no need for chain plates.

There is some bending load on the masts from the wishbone booms. It's amazing how much bending the masts can take when there is very little compression. And when bent, they can still rotate when you tighten the sheets, albeit with a little groaning from the plastic bearings. Of course, when you slack the sheet, the bending load is relieved and the mast rotates without complaining. All in all, there is no danger with these booms. They're over your head and there's nothing else for them to bash. But you can dispense with booms if you want, and just not use the leeward mainsail when reaching. Just like with the A-frame, you can sheet down to the boat.
Click to expand...

Hello High Tacker, are you still on the forums?
Perhaps you could lend some of your observations to this other A-frame discussion?
http://www.boatdesign.net/forums/multihulls/frame-masts-54941-3.html#post764410

brian eiland · Jan 27, 2016

Ikarus34200 said: ↑

Hi

I am the designer of the Voyager with the A-frame mast. The statement "of the self" glass fiber flag pole as masts is, as almost always, incorrect. It is a pity that articles etc are not really read anymore.
First this arrangement is no gimmick but there is a reason why I designed this A-frame mast.
First to unload the bridge deck from the high compression load imposed by a center mast rig (could be as high as 13 metric tons for this boat and sail area). This means the whole bridge deck can be designed much lighter. Result a faster boat and less material thus costs. See sketch.
Second, to set and lower a mast is not easy. Or you have to spend a lot of money for a crane or you need a device to do it by your self. In the Netherlands we are used to lower and set a mast by our self. Common is an a-frame which can be used as railing as well. My A-frame mast is going a step further. The whole mast is the A-frame. So you can set and lower the mast by yourself.
We use flag poles from Sweden. The have made extensive tests. With the results that I have a base for a lay up from UD glass and other material for the necessary strength. By the way the deliver the poles also without gelcoat, so nothing to sand for the extra lay up. The compression tubes are AL tubes.
To EEC regulations. I can only say that the spoiled all there credits and trust as the invented the regulation how much a bend a banana has to have to be suitable for consummation in the EEC. So forget it. What would the reach anyway? A more heavy rig could mean, that the weight when up side down, could be just to much, with the beamy boats of today, that the boat can not right it self anymore. Our Pelican is stable till 89°. With a more heavy mast he would go at about 70°. Attention this is a theoretical stability calculation. Don't try it in waves !!
Next point. I am not an American designer, but a Dutch designer.
A forum can be a good thing, but before you offer a meaning, research your answers for correctness otherwise you do more harm as good.
In any case have fun and remember the best captains sitting always on the wall .

Cheers

Bernd

The photo shows an A-frame mast on a tri. I made the photo last Sunday in Sete/France
Click to expand...

Are you still participating on the forum(s)?
Do you have some photos of the built Voyager??
Brian

brian eiland · Jan 27, 2016

Ikarus34200 said: ↑

Yes, this are the flag poles we use as BASE.
The compression is about double as big as the tension because through the spread of the loads.
Buckling load of the lower wind mast and cross trusses is the bigger problem.
Click to expand...

Ikarus34200 said: ↑

The bigger load is in tension on the windward side. So no problem here
Click to expand...

I was going back thru this subject thread this morning, and these two postings of yours seemed to be in conflict??

brian eiland · Sep 27, 2016

Review of these discussions

I was going back thru this entire forum discussion this morning, and making a list of applicable postings that might be considered if one were looking to build an A-frame or Wishbone shaped mast.

It really is quite an interesting subject thread with LOTS of good observations. :!::idea:

brian eiland · Oct 5, 2016

Double A-frame rig

Something that just got posted on another forum. I've ask the poster if he might have some photos or a sketch.

admiralslater said:

In 1972 my father Alan Slater designed and built his first catamaran . He did as much research as possible and as an engineer he was not afraid to think outside the box . This 30 foot family light cruising Cat. It features a double Bi pole rig ,he always called it A frame as the masts looked like a capital A . It had two frames both with the bases at the same place ,From the side it looked like a V. the taller frame leaned forward and the shorter leaned aft in sort of a Ketch arrangement .

The sail plan was a such,(all sails furling) forward a jib,a mizzen jib and in the middle of that V an upside down jib with a sprit to control the clue which we called the top sail.
THE advantage of the double frame was that you could get the same amount of sail up but with a lower overall height due to the topsail ,and not having masts the efficiency of the sails was increased . Windage is a valid point but for the most part the boat out performed the cruisers of the day
The masts were mild steel tubes hot dipped galvanized with hand spliced standing rigging . The tall frame was about 32 feet long .
This was our Family boat until about 1988 .

It was a dream to sail All the controls for furling where at the bottom of the V .You could go from full sail to nothing in 30 seconds ,we timed it once . She was called" Pandemonium" and to the untrained eye she looked bit like that. When I was young I took her to the Bahamas and back and the rig performed very well .
I seriously considered this rig when having our PDQ 36 built but the structure of the boat was not in the right place to accept the rig .

I would have no issues with owning a properly designed A frame rigged boat.
Hell if the Harkens did why not any one else
I have looked for her on the web but no luck . It was sold to a family in Flint Mich.If any one has news of Pandemonium let me know .last known colour was yellow.
David
PS I am not at home so I don't have pictures
Click to expand...

posted here:
http://www.cruisersforum.com/forums/f48/smg-50-its-like-they-were-reading-my-mind-79822-8.html#post2228016

brian eiland · Oct 10, 2016

Voyager cat design

Ikarus34200 said: ↑

Hi, I am the designer of the Voyager (cat) with the A-frame mast.
Cheers, Bernd

The attached photo shows an A-frame mast on a tri. I made the photo last Sunday in Sete/France
Click to expand...

Thought it would be interesting to post a few more details about Bernd's Voyager cat design.
http://www.ikarus342000.com/VOYAGERpage.htm

http://www.ikarus342000.com/VOYAGERpage2.htm

...posted some dwgs in case the website disappears (as seems to happen often these days)

brian eiland · Oct 10, 2016

SMG rigging detail?

Something that caught my attention as I looked thru some of the photos posted previously on the subject thread...

What are those rigging lines attached to the A-frame mast tubes between the two 'inner spreaders' ?

sharpii2 · Oct 10, 2016

brian eiland said: ↑

Something that caught my attention as I looked thru some of the photos posted previously on the subject thread...

What are those rigging lines attached to the A-frame mast tubes between the two 'inner spreaders' ?
Click to expand...

Those appear to be squaring shrouds, similar in function to upper and lower shrouds on a conventional rig.

The same problems exist for both it and the ''A'' frame rig. The mast must be held rigidly upright for the two stay sails to work properly.

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WishBone Sailing Rig

brian eiland Senior Member

Angélique aka Angel (only by name)

RHP Senior Member

Attached Files:

Aria.jpg

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brian eiland Senior Member

Spiv Ancient Mariner

upchurchmr Senior Member

CT249 Senior Member

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Attached Files:

Voyager cat, A-frame rig.jpg

Voyager cat. roller mainsail.jpg

Vogager cat, batten main.jpg

Voyager cat, top view.jpg

brian eiland Senior Member

sharpii2 Senior Member

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