Attach batten along full length with sail makers tape and then a patch of sticky back around the fwd and aft edges (aft one wraps around leech) to stop ends peeling away
Reason for question, is one local sailor “seems” to have ruined a set of sails this summer. He attached narrow strips of styrene to his sail using some kind of contact cement/glue -(I’m not sure of type)- but sail has taken on the “starving dog’s ribs” kind of look. The look seems very evident when on opposite tack as the batten side of sail. It looks via photos, like battens won’t “pop” to other side, so on one tack, it looks like a starving dog’s ribs.
It was my guess that the batten being glued full length kept batten kind of slightly curved, and thus a really bad sail setting when on port tack.
For my multihulls, I slot the trailing edge of mast and leading end of battens (full length) are inserted into the sail track with the trailing (leech end) attached with sticky-back Dacron spot and all inside a narrow sleeve. This leaves sail material to be free from battens, and allows battens to take on curve independant of sail, but fore/aft tension keeps the roach fairly tight and it doesn’t flap. Works fine for full length, and of course my short ones on 1 meter boats are totally attached as you describe, but they are short - less than 3 inches in length.
He has a couple that are nearly 9 inches in length, and I would hate to screw up another set of sails by attaching them by tape/glue the full length again, so thought I would run it by some others as to their experiences. I had it happen once a long time ago, (batten glued to .75 oz. lightweight ripstop) but I attributed it to the fabric stretching from the glued batten. Since then I haven’t tried it like that. Of course, Mylar drafting film might be an answer, but he does like his colored sails.
It isn’t a competition boat either, so it doesn’t “hurt” performance according to him - just looks bad. Does this change any suggestions?