Have you ever felt you've put a sail too big on any board? What happens then and how do you know it's too big? You gain nothing in early planing, handling is horrible, you may even start to sink.
Heavier riders will experience this with smaller sails than you. There's simply way too much weight and bulk on a board to carry. No scientific explanation here, but tried and tested many times.
Btw, I don't think that you can use 11m on an iS122 efficiently at any body weight. There are much better boards for that.
With regard to quoted sail ranges, I think they are a bit stretched: I use iS122 (85kg) and I think its ideal sail range is 7.0-9.0, maybe 9.5 if you're lighter.
Last edited by Screamer; 9th October 2008 at 03:32 PM.