The catch is that portion of the stroke where you get the blade of the paddle into the water.
a. Lean slightly forward and using your stomach and back muscles rotate (twist) around your spine dropping your shoulder and extend the paddle forward keeping the shaft of the paddle parallel to the side of the canoe. (This twisting will enable you to use the larger and stronger muscles of your back and torso). Your lower arm should be fully extended with your elbow straight. Your top hand should be at your forehead with the arm fully extended and the elbow slightly bent.
b. Once you have extended the paddle (reach) place the blade cleanly in the water without stabbing or splashing. Do not start the power phase of the stroke until the blade is deeply in the water (this will cause cavitation and you will not get full power from your stroke).