Jib sizes

I am looking to buy a new jib. The one I sail in the mostly light airs here is pretty high cut but I don’t know the size in terms of percentage.

I’m attaching a picture of Morning Star in Alaska, whose jib is a good deal lower cut than mine. I believe the extra effort forward from such a sail would assist in reducing my sometimes excessive weather helm.
Does anyone have an idea of the size of this sail, or a means of describing it to a sailmaker ?
I don’t have any contact details for Ron Downing the skipper.

IMG_2031a.sized.jpg

Hah ! Managed to find Ron on Facebook, and have asked him to comment !

Mike, before you make any decisions please take at look at my blog re: lee/weather helm. The jib you are wondering about I believe is the jib top. On my blog I also have the sail plan with all the dimensions.

Go to http://www.garyfelton.com/shanti/?p=401

Enjoy!

I see that someone has given you a link to sail dimensions but, for what it is worth, I generally pull the first reef in the main at 10-12 Kts…and sometimes a 2nd if the winds pipes up a bit more…meantimes, I will have the yankee and staysail completely out…balances the helm nicely and actually gives you a bit more boat speed because you are not dragging the weather helm rudder through the water.

Also, unlike some of our ‘rail down’ friends, I find that 15 degrees of heel…plus or minus…gives a comfortable ride and, again, good boat speed…maximizes the waterline at that point and anything more will also induce serious weather helm because of the hull shape. Not as exciting but better performance.

I concur with Tharrer. Weather helm can also be reduced by flattening the mainsail with a van/preventer rigged from the bulwark to the boom.