Drive/Recovery Ratio

© 2001 Atkinsopht (03/23/02)

For a boat on the water at a constant average speed (Vs) and a constant average rower effort there is one, and only one, stroke rate (R) and one drive/return period ratio (Td/Tr) associated with that speed and effort. Fixing the rating (R) fixes the stroke period (Ts=60/R) and constant speed fixes the length of time (Td) the blades are in the water--assuming that the sweep arc is not changed. If Td is thus fixed then the return period (Tr=Ts- Td) is also fixed which determines the ratio in turn. For a given shell speed, stroke rate and drive/return ratio are always together in lock-step.

Since a rower who wishes rapidly to change his stroke rate cannot do so by changing the length of the drive period (Td) the only course open to him is to change the recovery period (Tr) either by lengthening or by shortening it. For a given rating a rower cannot choose a particular period ratio--it is chosen for him by the physical characteristics of his system.

The rower may also change the rating by increasing or decreasing his effort but, because of the system momentum, the change is not instantaneous. As shell speed slowly accelerates under increased effort the rating gradually goes up and vice versa.

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