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Big head on a Cobra?


NixonJr

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i have found the bighead much easier to sail with. less sheet adjustment in the squirty stuff.

i think if you look at the open design classes, whatever you sail whether its mono or multi, they tend to go with whatever is fastest. some examples would be MOTH, 14 SKIFF, A CLASS AND FORMULA 18 AND 16 CAT. all of these classes are running big head mains.

the one question to be asked is: can you show me a competitive A class or Formula 18/16 without a square head main?

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Mitch

Agree to some extent. Big head sails are more effective on wing masts. However the Hobie Tiger uses a pear mast although it is very stiff. A better comparison is the Arrow. As you would know they have voted to adopt an 800mm head main. A prototype has been made and is being trialled now. Also an Arrow in Qld has been using a big head main with the same sail area for about 12 months. I've sailed in a number of regattas where I've seen it faster than Robbie Lea (current national champion) in light air. Even without the advantage of a wing mast you are still getting the grunt up where it is more usable and getting rid of the long foot which only creates unwanted drag. I definitely think there is some potential.

BTW - I've almost finished the specifications for the Stingray main - I'm just waiting on some figures from a second sailmaker to verify the design.

Cheers.

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I'd love to Brian as it's my home club and where I won the nationals a few years ago. It really depends on the dates as I'll be doing the A Nationals at Lake Macquarie. Do you know the dates?

As for the square top main - I'll see how the budget is going. I've got a big program coming up - Two weeks soon doing the A States in Vic and NSW then the Worlds in Denmark in August. I also hope to do the Worlds next year in Florida if I qualify. Anyway I've got two good "classic" mains I can use - haven't sailed the Stingray for about 18 months as I'm also doing some big multi stuff on my seawind and a friend's F82R. Sailing at the lake tomorrow on my A and with my daughter on her Arrow.

Cheers

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John - I don't think a wing mast is necessary, but I do think that a fairly stiff mast is.

From my understanding the mozzie and cobra masts are very flexible. Most of the Cobras are using Quantum mainsails and from a brief chat with the sailmaker he was mentioned that the more you bend a mast the stiffer it becomes (that makes sense to me but probably not somebody reading it), i think this is why many of the mozzies at the front of the fleet appear to have a lot of bend in their mast even in moderate air..... Hmm am i confusing myself?

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Haha funny joke Brian :)

Damien if you have the time to come down and want to we can do up an old cobra lease boat with all of the new systems that we use on our cobras.

Would come with a trailer and everything you need to get started.

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  • 3 weeks later...

From my understanding the mozzie and cobra masts are very flexible. Most of the Cobras are using Quantum mainsails and from a brief chat with the sailmaker he was mentioned that the more you bend a mast the stiffer it becomes (that makes sense to me but probably not somebody reading it), i think this is why many of the mozzies at the front of the fleet appear to have a lot of bend in their mast even in moderate air..... Hmm am i confusing myself?

Hi Mitch

Yes the masts are very flexible, so if we tried to sail with them straight they would flop all over the place like a piece of spaghetti. The amount they bend upwind doesn't vary a lot with wind strength as the bend is necessary to get the right upwind shape in the sail. 5-10 knots is probably the least bend as that's when we are looking for power. That's why Mosquito sails are so much harder to get up the mast than a wing-mast sail - all that luff curve.

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That is not a simple story. Mid 90's there were five Mozzie mains built with a square top but otherwise the same shape (the boom wasn't shortened). At the time it made the Taipan sail look like a pin-head. They tried it and found no measurable performance change, but it did look a lot nicer. So why did they vote against it? Who knows. I wasn't with them at the time. It was definitely a missed opportunity.

More recently (2000 to 2003) a real square top sail was trialled with an extra metre of mast length. It performed well in less than 12-15 knots, especially to windward, but the existing mast section that was being used really wasn't strong enough and needed an extra diamond stay up the front. The conclusion was that a real wing mast would be needed (like a Taipan mast), and in the end the vast majority of Mozzie sailors thought the gains were not worth the hassle of changing the entire rig (and the extra expense of a wing mast) - the current rig works pretty well, just doesn't look as cool as the new ones. The huge gains in performance by the simple addition of a spinnaker also made the tall rig less attractive.

Bob still uses his tall rig occasionally because he likes it and I think he gets a kick out of hassling Taipans with it.

I think the square top sail does a lot to make a class look more modern, but if it is going to cost a lot of money, time and effort to upgrade a class then I'm not convinced it's worth it. These are not boom times for sailing so we have to be careful not to drive people away.

So as far as the Mozzie is concerned I don't see any point moving to a square top sail as it just leads to a series of subsequent changes. First we would have to go to a wing mast. Then because we would be getting a hull out earlier there would be calls to add 300mm to the beam, and by then we would be only a squared off bow away from sailing a Taipan. So what's the point? If that's what someone wants they should buy a Taipan or an F16.

I hope this info is useful. I certainly don't want to try to tell the Cobras and Stingrays what they should do. Happy to answer questions though :)

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