Consider outfitting your yak with a sailing rig to power your kayak.
It is fairly easy to rig you kayak. kayaksailor.com offers this rigging system that looks fairly easy to attache to your yak for smooth sailing.
The system consist of a portable attachable sail and its rigging . The sail is operated with the pull of a rope and is easily retracted when not in use.
Now that you are adding as sail to your kayak, you may want to consider the use of a rudder. This is a highly debatable topic that naturally has advantages and dis advantages. The commonly accepted solution is to simply make the choice based upon you own personal preferences.
Watch this innovative sailing system in the video below.