spinnaker sizing for 12m cat

[moreton99]

Looking to get a symmetric spinnaker for those downwind runs up north. Went to Lizard from Brisbane last year and there was lots of opportunity for dead downwind. Already have a screecher(awesome thing) so symmetric sounds like a good combo. There is another thread on asymmetric v symmetric.

I have a 2 m prodder which I think is complicating things and making me unsure as well as my general lack on knowledge about spinnakers.

Measurements
I. 14.5m from top of the screecher halyard to deck
J. 6 m from the mast base to the prodder end
Max Hoist? 15.7m to from the of the screecher halyard to prodder end.

Looked on the rollytasker site and I think size 8 is the correct one. However there is a 14 m spinnaker for sale with a 9 m foot which I think might go well after you take out the loss in length for the sock . But its over a meter wider than the rolly tasker size 8??

My questions:
Have I worked the sizes correctly?

Is it a big deal if the used spin is a meter wider?

From reading, most cats run the spinnaker from the bows so should I be measuring from there rather than the prodder end? Why not?

Any comments or good resources or info so I get a better understanding of these sails to make sure I'm on the right track?

[Tin Tin]

For cruising as long as your luff is around the "I", you can go quite wide on a catamaran ie. go for as long a foot as you can get, its just more horsepower. If your luff is too long the kite will sit low and impair vision and drape over you prodder. You can fly the symmetric two ways. 1. With 4 sheets. From each bow an adjustable tack line to the clews and a sheet to each rear block. This enables the kite to be placed precisely for optimal sail shape down wind, keeping the foot parallel to the sea and makes gybing a non event. 2. You can use a set up similar to an assymetric, where one clew is actually used as a tack attached to an adjustable bridle between the bows so the sail tack can actually be brought to the centre and so you can run on a broad reach quite effectively. Gybing is a hassle though, although with no mainsail up the kite will still be quite effective even sailing by the lee. Tweakers are a handy addition to control foot height, these utilize a snatch block and can be attached by a dyneema loop on the midship mooring cleat.

[slug]

Originally Posted by moreton99

Looking to get a symmetric spinnaker for those downwind runs up north. Went to Lizard from Brisbane last year and there was lots of opportunity for dead downwind. Already have a screecher(awesome thing) so symmetric sounds like a good combo. There is another thread on asymmetric v symmetric.

I have a 2 m prodder which I think is complicating things and making me unsure as well as my general lack on knowledge about spinnakers.

Measurements
I. 14.5m from top of the screecher halyard to deck
J. 6 m from the mast base to the prodder end
Max Hoist? 15.7m to from the of the screecher halyard to prodder end.

Looked on the rollytasker site and I think size 8 is the correct one. However there is a 14 m spinnaker for sale with a 9 m foot which I think might go well after you take out the loss in length for the sock . But its over a meter wider than the rolly tasker size 8??

My questions:
Have I worked the sizes correctly?

Is it a big deal if the used spin is a meter wider?

From reading, most cats run the spinnaker from the bows so should I be measuring from there rather than the prodder end? Why not?

Any comments or good resources or info so I get a better understanding of these sails to make sure I'm on the right track?

Don’t know your boat

With downwind sails bigger is not always better

Particularly in light wind

A big sail has more mass , is unstable and won’t float correctly in light air

From the practice side a big sail is more difficult to handle with a snuffer

[moreton99]

Thanks for the comments, very helpful.

[Chrisatlantic]

The 14m by 9m kite should do fine for you.