  We present a study of the hydrodynamic characteristics of sea kayak paddles
without taking into account the kayaker. We focus on traditional paddles used
in the Arctic, one from Greenland and one from the Aleutian Islands. A basic
modern European paddle is included in the study for comparison. First the
paddle stroke parameters specific to sea kayaking are identified because
previous studies were devoted to a competition context. The hydrodynamic force
generated by the blade motion is detailed: two terms are identified, one
involving the inertia of the water surrounding the blade at the beginning of
its motion, and the second term is the classical drag/lift force. Drag and lift
force coefficients were measured in a wind tunnel. The data allow computation
of the hydrodynamic force during a paddle stroke. The European paddle was shown
to be more efficient than the traditional paddles because of its shorter length
to width ratio which contributed to a larger inertia effect. However, the force
obtained with the traditional paddles better follows the imposed motion by the
kayaker so that they are more comfortable and less tiring in the context of
long distance trips, as those practiced in sea kayaking.
