Forward dynamic model for rowing performance; driven by rower specific data and variable rigging setup

Abstract

In this research the influence of the rower behavior and rigging setup on the boat performance is investigated in a data-driven model. There are different rowing styles and techniques between rowers. Making rowers row in synchrony, while important for the boat performance, is not easy. Rowers have their own signature rowing curve, of which only few aspects can be changed. The signature rowing curve can be based on the oar angle or the relative displacement of the rower. The latter is assumed to be constant for changes in the rigging setup and therefore preferred.
The data used in this study comes from a woman’s double, the rowers of which are members of the KNRB. In the boat measurements are done on the gate and foot forces, as well as the oar angles, the seat displacement and boat accelerations.
From the free body diagrams of the different parts of the system, a one-dimensional rowing model is derived. The model is driven with the measured forces on the rower and the oar angles. It can be validated with the measured boat accelerations. The distribution of the masses in the system are slightly changed. All drag force on the system is assumed to be viscous and is assumed to be proportional to the square of the boat velocity. The lateral forces on the blade and the oar deformation are neglected.
The relative motions of the rower are best predicted with the forces acting directly on the rower, after a compensation of the measured foot force. The best fit for the boat accelerations are found by combining the system acceleration with the relative accelerations of the rowers.
With the assumption that the rower can be modeled as a force constraint model, the rigging setup of the modeled boat is changed. The blade forces have a leading role on the resulting boat motions when changing the rigging parameters. However the blade forces might not be realistically modeled. Changing the lever ratio of the oar, by increasing the inboard length leads to a bigger covered oar angle and a higher boat velocity, but a lower work per stroke applied on the handle by the rower. Moving the footstretcher towards the bow of the boat shifts the oar angle and leads to a higher boat velocity and lower handle work per stroke as well. Changing individual rigging parameters did not result in big differences between the rowers.
No indications of improved synchronization between the rowers are found and the energy balance of the system is disrupted. The model simplifications of the blade forces may not be justified. After implementation of a more complex modeling of the blade forces indications of the synchronization might be found.