For the sails to be an effective means of propulsion they need to transfer a lot of force through the mast and stays to the hull. This require the attachment po

For the sails to be an effective means of propulsion they need to transfer a lot of force through the mast and stays to the hull. This require the attachment points to be very solid. Not something you can easily do as a retrofit. You'd need to reinforc the hull aroud the mast and stay attachments.