How to measure an ATS

Hello NG-members,

I'm considering an ATS and I'm trying to define the right measurements,
particularly the luff-length.
Are there any rules of thumb that apply here?

What luff-length is appropriate with a forestay-length of 20 meters?

What is the difference in height (re the luff-sheet-eye) between
sailing the ATS a) downwind and b) slightly upwind ?

Thanks and fair winds,

Len.

Jere Lull wrote:

> Luff length is slightly less than the distance from the halyard sheave
> and the downhaul turning block, or approximately your forestay length,
> maybe a few inches shorter. You definitely want to be able to flatten
> the luff for close reaches.


Thanks,

What is your experience with an ATS on downwind courses with say 2 bft
but with a bit of sea from the previous days with 6 bft.
In my expectation an ATS wil stay more or less continuously filled
where other sails start to flap vigourously on the beat of the roll.
Am I being over-optimistic here?

Regards,
Len.