On some of my sea kayaking trips I like to use a small sail.
I have designed my own rig and a few of my friends are now using the same set up.
Details on DIY sail can be found here.
While sailing can be great fun and can add a few more miles to your daily paddling distance (that's if the wind gods are benign to you and won't give you head wind) it can also be more challenging than just paddling.
The kayak can become more tippy in higher winds with increased wave heights.
Occasionally a kayak sailor will find him/herself in a gust of wind that just were not ready for and capsize.
Some sail rigs are rather cumbersome and don't stow away easily.
Those rigs will be more difficult to handle in case of a capsize.
The design I use has a single main sheet (one rope that goes to the boom) that with a simple flick of the fingers will depower the sail and possibly allow you to roll your kayak.
I have been lucky enough not to capsize yet in windy conditions and I am unsure if I will be able to roll back up in the heat of the battle.
On a recent trip I wanted to see if my friend Vanilla could actually pull off a "sail roll".
Conditions were not really windy but that allowed me to be next to him and document the roll.
To be able to successfully roll with the sail Vanilla let the sail out so the boom was loose.
In case of an accidental capsize that would be the first thing needed to be done or the sail would hold water and prevent rolling back up.
During rolling, the extended paddle generated more lift, especially the Aleut paddle.
An alternative roll with the sail would be to release the uphaul (rope that holds the mast up) and have the mast loose.
Once back upright the sail would be deployed (uphauled) in the usual fashion again.
I have observed several rigs on local kayaks that used my dimensions for the sail but rigged the sail with some mistakes in the set up.
Those sails can only be used in light winds where realistically the chance of capsizing is substantially diminished.
If rolling your kayak is not a skill that you already have, be prepared to have a swim or two if you use your sail in decent winds.
Make sure you know how to rescue yourself too or the swim back to shore could be a very long one.