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Shellgrit

W14 Square Top Main

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Have just started using a square top main. The boat, as is, has done well under the previous owner in competitions. I am sailing cat rigged and the sail feels like a wet blanket; unresponsive. Sail tell tales unresponsive to sheet tension. Middle leach tell tales constantly hooked forward. So boat does not keep up with the fleet. I think my problem may be basic. Any suggestions on what to check?

One fellow sailor I checked with says he doesn't look at his tell tales so should I be looking for some other guide?

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Continuing on from the post on the Australian Catamaran Forum..
The main issue is probably a combo of too soft battens / mast rake - and possibly a too loose rig...
The thing to do is to hop on someone else's boat - and they sail yours for a while - trading tacks etc - so that a comparison can be made...
if you can get a 3 or 4 boat 'swap' going - this is enlightening for all concerned - and will highlight any faults in your own boat...
Or, send some photos here - taken from behind the boat; sail sheeted on tight with traveler centred - or very close to centre with enough luff tension to remove all creases from the leading edge...

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Thanks again Prince,

Am getting some confidence in what the problem is and how to tackle it.  if I go for stiffer battens what grade/rating/description would you suggest ? 

Shrouds are set at 3rd hole from the top. Rake the must back a bit?

Luff tension should be just tight enough to remove all creases?

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You should be just shy of block-to-block when sheeted on hard in a strong breeze - 15 knots +
So, mast rake is determined by that... and the less 'slop' you have in the rig - the more responsive she will be...
Luff tension should always be 'full-on' - and even more so in a strong breeze - give it heaps. Of course, off-wind reduce luff tension according to wind strength and the set of your sail...
Take your battens (and sail) to a local sailmaker - he will show you the curve in them - (basically, put one end against a wall or something solid - and push) - and then get some stiffer/heavier ones ordered...
Make sure the maximum draught (camber)  is no further back than 35% - 40% along their length - in other words you want the drive 'forward' - and a 'clean' aerofoil exit to the shape. Generally the top 3 battens should have less 'depth/camber' than those below. You get power from the bottom 2/3rds of the sail going upwind, and the top 1/3 should really be laying off and 'feathering' - especially in stronger breezes where it just adds to healing, and doesn't add to speed...
Downwind the top 1/3 is being utilised for even more drive - but the balance must be found carefully, as too much power can quickly lead to a pitchpole on a broad or close reach... too much 'fun' - huh?
;)

Anyway, there are plenty of articles online talking about cat sail / batten shape - just do some research...
Of course, these are just general guidelines... you really MUST get some 'boat-to-boat' comparisons happening...

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Prince,

Will have to get some more practise.  Have contacted the previous owner who says he did replace original battens with stiffer ones issued by Windrush.

With a pin head sail flatness is achieved by sheet tension.  Is it the same with a square top?

 

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There's really nothing more I can add... sorry.
if you sail with a racing fleet - this kinda basic question can be answered by anyone who's prepared to listen to your concerns... and put your boat next to theirs and 'play' around with things...
PP

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