Hopefully you will see below a simple downhill sail (up to 40 degrees) which does not require cutting holes in the deck for the mast. Safe to use since if it is over powered it will just flop to the side releasing the air. No need to hold the sheets so you can use the paddle for bracing if required and you just release a velcro tie to put the sail up or pull both sheets to take down. This picture was taken in wind speed less then 10knts but have used it in 25knts without worry. Very simple to make and only about 6 stitches needed for those who don't like sewing.
Email me if you want instructions.