Its a topic that has been talked about here a few times .
On brand new sails , especially cammed , it seems to be common practice to have your battens set a bit on the loose side with a few small crinkles for the first few outings . Apparently to let the sail stretch . Then tighten the battens . This is what i do .
But on closer thinking ......
Wouldn't it be better having the battens tight so that the sail stretches to the correct batten curve ? Instead of stretching first then having to stretch again to a proper tensioned batten ? Ive never read that they should be loose first in any brochures ive seen .
On the new North race sails they specifically say not to touch the battens at all . They would have to set them on the tight side so when the sail stretches they wont become loose . Mabee they know something and we have been doing it wrong ????
I dont think its the same as running in an engine .
Hi Imax
It is no problem to tighten the battens before the first time on the water.
In general even if the battens are set tight the first time, then after 1-2 times on the water - the battens most likely need a little tuning (tighter), as the material stretch in a little.
Even if some brands say don't touch the battens as they are set tight, then I would be surprised if you could crank the tension a little further after a few sails.
In general going from the foot batten and up the sail
Foot batten can be cranked pretty hard. As you want the curve down this part of the sail
Next batten up nearly as hard as this is the power zone.
Batten above the boom , depends a bit on the brand and design. but don't go as hard as the ones below.
The next battens up I would just say tighten only so the wrinkles is away (quite light tension really), as you don't want to much curve here, that can 'hook the leach' and pull you around to much.
Cheers
Jesper
OK now a thread hijack but similar enough I hope ..... 
How much does a wave sail stretch in the luff? I'd expect it to need a tiny bit less downhaul (well, shorter luff) for the first couple of sessions but I wonder how much?
My new sails seem to have insanely too much leech looseness with recommended downhaul - but feel great....
How much is the difference in luff length from brand new to a bit used? 1mm which is imperceptible? Or maybe 10mm plus, which would be a clear difference when rigging after a couple of sessions?
And Jesper, are your comments re: tension from foot upwards also relevant to wave sails?
Hi Mark
The stretch in the luff for a wave sail you would not be able to notice really. If the sail is designed well, then I could not imagine it to stretch more than max 5mm over time. The first time out if might 'stretch in' a little. Just from the tension through the pulley (webbing) and top webbing / material mostly.
The luff don't actually stretch much as most of the tension runs in a straight line from the pulley and up to the top of the sleeve. So that is also why there is quite a few reinforcing layers at the top of the sleeve, to deal with the load.
The printed suggested downhaul setting is to be taken a bit 'lightly' on some brands. Take it as a guideline I guess,,
For the batten tension the same apply as for the race sails. Most tension on the bottom battens and less towards the top.
All a bit of fine tuning really.
Agree with Jesper... I would not expect excessive luff stretch...the leading edge takes the load and is generally well reinforced with most brands running kevlar or equivalent to minimise stretch.
Cool thanks guys
I never really thought about batten tension change from top to bottom, but makes sense.
