A frame mast concept

[Norman Brown]

The new masts (inverted whishbones set as 'A' frames) on my boat are slight wing form made from a former as clam shells. Then externaly wrapped in carbon. A drawing was posted in feb. if you look up Lionhart.

[brian eiland]

Originally Posted by Norman Brown

Amoco Procyon was a interesting experiment.

Did you happen to visit this subject thread,

PROCYON project........a Bold experiment

[Norman Brown]

Yep. Got all that Brian. Could do with more from the people who sailed her as a comparison for windward performance. But I am sold on the idea and the figures look good so the masts are being built at the moment. The hull is going in the water in 3 weeks time. All I want now is a morgage on the morgage on the morgage on the morgage........ I think you get the picture. Sailing will not take place until late in the year.

[brian eiland]

If I remember correctly there are some sailing comments within that thread by Olaf Harken himself, and his captain ??

[Norman Brown]

Yes. I have been through the threads. Olaf has a few words but it does not do justice to the boat. A sailing comparison with other yachts of standard rig would be a useful tool. A polar diagram. What the feel of the boat was like in both light and heavy air's. Handling in a gale. As a experiment all sorts of info must have been put together. Who has it ! ? Randy West would be interesting to talk to !

[tspeer]

Originally Posted by Russell_Miller

It'd be interesting to conduct the experiment again with a skin around the frame to help the aerodynamics out. When people home build carbon spars they'll build round sections (cause its easiest) and then add a better leading edge from a less expensive material that won't affect the spars bend characteristics.

What apparent wind angle will the skin be based upon? I believe this question, more than simple easy of manufacture, is what drives round sections.

[Russell_Miller]

Tspeer

It all depends on the type of boat and what you reckon the upwind speed you're designing for will be. It really wouldn't matter what the shape of the skin is, as long as you're ok with the aerodynamics of it i guess, i think anything would help to keep the advantages of an "a-frame" type mast and address the disadvantages.

[CT 249]

Originally Posted by Norman Brown

Yes. I have been through the threads. Olaf has a few words but it does not do justice to the boat. A sailing comparison with other yachts of standard rig would be a useful tool. A polar diagram. What the feel of the boat was like in both light and heavy air's. Handling in a gale. As a experiment all sorts of info must have been put together. Who has it ! ? Randy West would be interesting to talk to !

I saw some results years ago that did not show the speed in a flattering light. The only "outside" perspective I can see on the net is this one;

"With all respect to Olaf and Harken's far-sighted
Procyon project I recall seeing that boat from the Pied Piper's rail, Dick
Jennings' six-time Chicago Mac line honors holding Santa Cruz 70. We were
sailing off Milwaukee before the Queen's Cup and saw the intriguing
Procyon. Pied Piper hardened up and closed with them on a parallel upwind
course. After a few minutes sailing slowly backwards, Procyon broke off
this interesting comparison. We did get a laugh at their course change. I
don't ever recall completing a port-port race and finding Procyon in and
tied up to the bar ahead of us. Maybe they hadn't gotten their numbers
worked out yet. It was an interesting collection of ideas."

Interesting that the claimed 15% increase in upwind speed certainly didn't work out. It seems that the reality fits closer to the views demonstrated by wb sails and Tom Speer, and that a single mast is better.

Interesting too that the world's fastest boat; the world's fastest windsurfer; the world's fastest offshore yachts; the world's fastest dinghy and the world's fastest skiff all have big mains and all bar one (the very specialised MI) have a mast in front of that big main. The "no mast" idea has been around for many decades and it has yet to be successful.

As Gggguest says, the interesting thing about wing masts is that they generally don't seem to provide anything like the performance advantage in reality that they do in theory. They have, after all, been around since the 1930s and in all that time, their success has been pretty much limited to a few cat classes.

When theory (or at least a theory held by some) is disproven time and time again by practice, maybe the theory is wrong?

[Norman Brown]

Maybe she just did not perform as a hull. Info from people who sailed her would be interesting. I am comitted ( I should be !) to this type of rig.
It offers me what I want from the boat.

[Brent Swain]

There is an aluminium fishboat on the BC coast, which as an A frame mast with a roller furling main , vertical betwen the frames, and a roller furling jib foreward. Called "George" something. Looks slick.
Brent

[brian eiland]

Quite a few more bi-podded, A-frame, wishbone mast discussions here:

WishBone Sailing Rig

[Norman Brown]

Now the interesting point is: Should the wing shapes point outwards or inwards. when going to windward the most exposed mast is the windward so they should have the pressure drop facing outwards inorder to pull the boat upright.
But the fastest air is coming off the genoa on the down wind side of the boat. So the pressure drop should face inwards in order to pull the boat upright.
Ho. It's a quandry !

[Number One]

Hi, my name is Gerhard. Iam living in Cape Town at the moment, but i am an austrian. Yes austrian - not australian. I designed some years ago for me and my wife a "easy to use" conzept for a 50ft Cat. Because i like fast sailing, and me wife is worried about that, i must find a solution. It must be possible to sail alone with the boat, to reef the sails in all condition and al courses witout stress. I think you know what I mean. The solution war for me was the A frame Mast. I made it - together wit a spezial hull design, we call it ULDP hull (ultra low draft performance) with only aprox 800mm draft. Now after tree years, i must say, it was the best idea of my boatbuilding life. The idea war so god that I must start two Years ago with a prof. boatbuliding here in SA.
You ca find some arguments for the A frame mast on my Web site; www.sail-the-difference.com . If you have some questions to the mast or the concept, ask me.
I also sailed with some editor from sailing magazine in europe, but they didnt wrote properly about the concept. An editor said to me behind the hand. "If we write the reality about your performance, then we get a Problem with the big companies in the Multihull industrie, which pay every month a lot of advertising!?That was the reason that we sailed a race some weeks ago. With a skipper which learnd to sail two years ogo with the "number One" . It was also his first race! The cat class was easily won by Number One. In the tree longer Distances(all together about 9 hours) she was 1h24 min in front of the next cat. Much more important for me was, Number One was able to tack better than many of the fast monohulls taking part of the race. Reaching in 18 Knots of true wind she achieved 11-12 knots up wind and whilst beating her VMG was 6.5 Knot!!! That with a 17,3m Mast with 90m²sailaera and no daggerboard! Best regards Gerhard

[Norman Brown]

Thanks very much for that info. The pic's don't realy show the size and details of your rig. Have you any ?
I am glad to here from someone who has actualy done this instead of pontificating.
Have you come across any mono hulls with this rig ?

[brian eiland]

Originally Posted by Number One

Hi, my name is Gerhard. I am living in Cape Town at the moment, but I am an Austrian.

The idea war so good that I must start two years ago with a prof. boatbuliding here in SA.

You can find some arguments for the A frame mast on my Web site; www.sail-the-difference.com . Gerhard

I believe I've referenced your website in several of my other discussions on this forum. You might consider posting your observations over on one of these other discussions where there are a greater number of folks that have made contributions to the subject matter; ie,
WishBone Sailing Rig

...and the reference to SMG
WishBone Sailing Rig

...you might have been referenced under 'boomless' subject as well



But I do have one question for you. Why did you find it necessary to have a forward cockpit now that you have a furling mainsail??