As Walkabout says, Paddle bows are generally between 3 and 4 ft in length, and have very short draws. The draw weight and length depend on the board width and length, thickness, backing, and your tillering skills, as always.
I saw one on another site the other day that is a 37 inch Atsugewi style sinew-backed paddle bow that pulls 55 pounds at 22 inch draw.