For efficient propulsion through the water on your kayak, the Impulse propeller drive is hard to beat. This is the standard kayak drive provided with a variety of kayak models on the market, including:
Riot Mako 10
Riot Mako 12
Riot Mako 14
Riot Mako Inflatable
Point 65 Kingfisher
Sportsman Warehouse Lost Creek
With a little customization of mounts, it could work with your own DIY pedal setup as well.
Weighs just over 8 pounds, and is easy to pedal through wind and current. Comes with the regular-size clear splash shield, which will work on most of the above models.