Using theoretical principles, the components of drag (friction D F, pressure D PR and wave D W) of a single-seat kayak were analysed. The purpose was to examine the effect of changes in wetted surface area due to changes in kayaker's weight and the relative contribution of D F, D PR and D W to the total passive drag as function of velocity. The total passive drag values were based on experimental data collected in a single-seat kayak. Three different kayaker simulated weights were tested - 65, 75 and 85 kg. D F was the drag component that contributed the greatest percentage (between 60 and 68% at 5.56 m/s the top velocity tested) to the total passive drag for all the velocities tested and simulated weights. D W was the most affected by the increase in kayaker's simulated weight, mainly when comparing 65/75 to 85 kg. Results support the importance of a kayak design selection that minimises the kayak's drag for the individual weight of the kayaker. Also, the results suggest that the path for better hydrodynamic kayak performance should seek changes that can reduce D F, D PR and D W with D F offering the most potential to reduce passive drag.
Keywords: Hydrodynamics; drag decomposition; passive drag.