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  #1  
Old 07-15-2004, 02:37 PM
wannabe wannabe is offline
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sails on outriggers?????

Is it possible if you have a canoe with two out riggers to mount sails on each of them instead of the canoe itself, would you then get twice the sailpower??
or is this a typical newbies crazy idea??
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  #2  
Old 07-17-2004, 10:41 PM
sharpii2 sharpii2 is offline
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biplane rig

Hi

This idea has been tried on catamarans. The key to success is to keep the two rigs as far apart as possible. This is because what you will have will be in effect two sailboats sailing next to each other. The boat (or rig) to the lee (downwind) suffers. It doesn't get as much wind as the one to windward. The further apart these two rigs are, the less true this is. Even so, it is hard to get the same kind of drive you'd get from a single rig of equal area.

There are some advantages however: 1st, the center of area is lower, which lessens the overterning force of the rig, 2nd, with a cross spar at the mast heads, it is possible to form a rigid truss by running shrouds from the top of each mast to the base of the other mast, and 3rd (in your case), the center hull can have a higher cabin top, and 4rth, when running down wind, the two rigs will not blanket one another as much (assuming they are one sail each).

If you do try this, I would suggest that you do it with a trimaran rather than a double outrigger. The difference being that each outward float on the trimaran has enough boyancey to support the whole fully loaded vessel where, with the double outrigger, that is not the case. Also, with the trimaran, the outward floats are more rigidly attached to the more rigid cross beams. This helps in dealing with wringing forces caused by the sails trying to drive the vessel forward. Another suggestion would be to have a cross beam right under both masts which goes accross the entire vessel. This would be to (in the case that you don't use shrouds) deal with the twisting force caused by the wind pressure trying to knock the rig down, or (in case you do use shrouds) to keep the rig tensions from pulling the two outer floats together. It would be an interesting project.

Bob
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  #3  
Old 07-18-2004, 05:28 AM
mistral mistral is offline
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Hi, you may take a look at new Yves Parlier's project for a racing 60 ft. biplane at his site, www.parlier.org . The solution seems quite interesting on the drawing board, but taken on the Atlantic rough seas, Parlier's boat is not performing very well
Is it a setting problem due to the project's youth??
or maybe it's just a crazy idea with an uncertain future????

fair wind
Mistral
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  #4  
Old 07-19-2004, 01:39 AM
sharpii2 sharpii2 is offline
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biplane rig 2

Hi Mistral:

1st, it seems Mr. Parlier is trying several new ideas at once. Not only is he trying the biplane rig but he is also using stepped hulls that are very much like seaplane floats. These (if properly designed, which I assume they are) should be very effective in real blowing conditions. In lighter winds, I would expect the steps (which are really shallow wide transomes) to cause an unreasonable amount of drag. I suppose the extra sail area permitted by use of this kind of rig was supposed to make up for that.

2nd, Just because the biplane rig may prove deficient as a RACING rig does not necessarily make it deficient as a CRUISING rig. A cruising boat has different needs than a racer. Ease, convenience, safety, and minimum cost are all primary vertues of a cruiser. Where speed and, to a lesser extent, safety are the primary vertues of a racer. I think it is a great mistake to believe that these two very different types should neccessarily even look like one another let alone have the same kind of rigs.

Think of it this way, you can completely douse half the rig on a biplane rig and still have roughly the same center of sail area in relation to center of latteral area (there by maintaining the same steering ease). This would entail no tying of reefs, no expensive roller furling, and not having to stop the vessel at all. Just a couple of down hauls would do (just remember to douse the windward rig). This would prove most useful when suddenly caught over powered in an unexpected gust, especially on a multihull.

Bob
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  #5  
Old 07-19-2004, 03:09 AM
mistral mistral is offline
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Quote:
Originally Posted by sharpii2
2nd, Just because the biplane rig may prove deficient as a RACING rig does not necessarily make it deficient as a CRUISING rig.
I completely agree with you Sharpii2, and I add my 2 penny ; consider that on small sized yacth this solutions bring back interest upon unstayed masts, wich are a great way to reduce cost and increase semplicity of rigging.

Mistral
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  #6  
Old 07-19-2004, 09:33 AM
SeaDrive SeaDrive is offline
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Thomas Firth Jones (Google him) tried a biplane rig (as he called it) on a 24' catamaran. He changed back to a conventional rig after a season or two. He found that there were advantages on some points of sail but that, for cruising, there was too much of the time that one sail was blanketing the other. I'm sure he'd explain if you asked him. The late Neils Lucander tried it too, about 30 years ago, I think.
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