Modelling the deflection of rowing oar shafts

Abstract

The deflection of rowing oar shafts subjected to a static load was investigated. Two sets of sculling oars of different design stiffness were tested at three different lengths from 2.66 to 2.70 m. Loads up to 201 N were applied to the blade end of the oar shafts, and deflections were measured at six positions along the length of the shafts. The experimental results were compared with theoretical predictions obtained by modelling the oar shafts as homogenous end-loaded cantilever beams. The results show that the oar shafts are not uniform, in contradiction to the assumed model, but rather are most compliant near the sleeves and up to 80% stiffer towards the blades. The effect of oar shaft stiffness and length on the deflection angle at the blade end of the oar shaft was at most 1.18 ± 0.01°. The measured variation of stiffness along the shaft has implications for boat propulsion and rowing performance.

Physics of rowing oars

“…The propulsion phase is more debated as underlined in the review of Caplan in 2010 [13]. All authors agree that the initial acceleration phase is dominated by drag [14] but once the boat reaches its steady motion lift plays a role [15,16] as well as the elasticity of the shaft [17][18][19]. Theoretically, most of the studies are developed in the footprints of the pioneering work of Alexander [20] and show that observations can be satisfactorily approached with a one dimensional momentum balance, infinitely stiff oars with inertia and non-infinitesimal stroke angles, and quadratic relationships between force and velocity for the boat and oar blade [21].…”

A Rigorous and Integrated On-Water Monitoring System for Performance and Technique Improvement in Rowing

“…These systems, however, usually provide specific measurement data by using rather simplistic statistical analysis tools for supporting the coach and the athletes during the training process. Moreover, there exist more complex systems [2,13] based on field rowing data, experimental data obtained from ergometers [14][15][16][17][18][19], or even simulation data representing the rowing process [20][21][22][23][24][25][26][27][28][29][30].…”

Validation of CFD simulations of the flow around a full-scale rowing blade with realistic kinematics

“…where EI G z is the product of the Young's modulus by the second moment of area along the z axis and at the point D. It is also called flexural rigidity and its value along the oar axis was studied by Laschowski et al [7]. Different values are chosen for the linear or angular deflections for a better fitting:…”