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NixonJr

Square Top for the COBRA!

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Hey Guys,

What does everyone think of having a square top mainsail on the cobra?

I know there has been some talk of this before, and the real question was will the mast hold it up or just snap?

Also the Vic Cobra state titles are on a Lake Boga over there EASTER REGATTA!

See you all there!

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Hi Robert

I would love to see a square top on the Cobra as there isn't to many cats you can home-build on a budget these days with better performance and modern looks and may be an extra square mtr of main to keep heavier guys in the class? "just an opinion"

Cheers :-)

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if your going for a square top, youll want to run a stiffer mast. not for strength, but due to the concept of the square top. with a pin top mast, you use the mast to lay off and depower, however in a square top sail, the sail lays off... you dont want both happening...

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Hey guys,

So I went and ordered a square top for the cobra!

We got it just in time for Easter and for the vic state titles,

We have also kept the same sail area as what we used to have,

So there is no change to same area.

Results speak for themselves with myself winning 5 out of 6 races,

However on the last race I used my old sail and let someone else use the square top and was still out in front!

We haven't had time to do alot of club racing however early results indicate that there is no problem with our masts!

The feedback we have had so far is that most people are welcoming the change and do like the idea of a square top,

As with any changes so people want them, some people sit on the fence and some people don't want any change,

However as technology changes we need to keep up and not fall too far behind,

As a class we dont want to be changing masts, hull shape or change to the material of the hulls/ weight of the hulls,

The cobra is to be built from Fiberglass or Timber and thats it - No carbon.

I feel if we are to change anything that the sail is the only thing,

This way its just a simple change over nothing else needs to be changed,

And most people agree about this but we do need everyones input before an official rule is made on it.

post-15551-13778265955876_thumb.jpg

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Rob,

Looks interesting. Can you upload more photos?

What were the dimensions you worked with? Would you see the class moving to a new set of dimensions or just opening up the rules to a set of maximums to work inside so that each crew can come up with a sail that suits their weight, conditions, etc?

Matt

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None of my business but I think the mast issue will come into play once there is a fleet of these. It isn't the big head that causes the extra loads on the mast and if you keep the same mainsheets and cunninghams the mast will probably be fine, however, once you've done some two boat testing you'll find that leach and luff tension are vital so you'll add purchase to both the mainsheet and cunningham both of which will add significant amounts of compression to your mast and that is when you'll start having issues. So if changing the class rules to allow a big head make sure you should also change the rules to limit the main and cunningham to whatever is typical at present (I'm guessing both are around 6:1).

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Current downhaul is 8:1

and Mainsheet 7:1

Ill try and find some more photos however there isnt alot as it has only been used twice - once at lake boga and once at parkdale yacht club in class races,

In the past people have tried going to a bigger than the 8:1 on the downhaul, however this seams to make the block not actually want to turn and the rope ends up just sliding instead of the block turning,

As a class we are still working out the regulations that would be adopted to change the sail design,

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