does anyone use 'um? if so what do you use? i was thinking like really thin aircraft ply?:rolleyes:

I use clear plastic from the top of shirt box`s. Some seamstick tape and your done.
If you wish you can add a batten pocket from the sail material also just stuck on with the seamstick ( sailmakers double sided tape)

Going to try the batten pocket idea on next set of sails for the multihull. I tried the stick-on battens (thin styrene strips) and it gave my sail a “starved dog” rib effect.

For real stiff battens for heavy winds, I have used plastic from windshield wiper boxes, pallet strapping plastic tape, flexible poly report covers, and event tried several layers of insignia cloth. For short battens, the glue/tape-on idea works - but for full length or real long ones, it seems the battens need ability to move to allow opposite bend to take place during a change in tack. Glued on, full length strips, keeps this from happening.