I estimate the forestay length by sqrt(i^2 + j^2) and then require the sail to be between 90% and 98% of the estimate. These can all be changed by the user but I would like the first sort to get too many sails and not too few.
The sails from SailM8 are 84% or 19.4 feet vs my estimate of the forestay of 23.2 feet. I know you might need room for a furler but 3.8 feet? That would be a pretty big furler for a pretty small boat.
Does anyone have the forestay length and/or max-luff of a Cal20? Also, what is the luff length of a class jib?
For reference, here is the listing for the sail I am wondering about
