Thank you much for you replies. The information are really very helpful.
Unfortunately, it's 4200KG, around 9000lbs......
I'm using dacron sails, but there's no cunnigham at all I'm wondering is it normal?
I'm going to replace my main sail, what are difference between full batten and half batten, inspite of the price? Also I found one strange design from Sailseast, which the top two are full batten while the botton two are half.
http://www.sailseast.com/Products.htm
Do you think the design is good? By the way, I really don't like their service totally not helpful....