Found this great image on an academic paper about whether training on a Rowperfect was a good way of selecting scullers.

The researchers end by saying
CONCLUSIONS: Static ergometers have previously been used almost exclusively for on-shore training and crew selection despite research indicating that they may not represent on-water rowing. The advent of dynamic ergometers such as the Rowperfect are reported to more closely replicate the inertial properties of on-water rowing and would therefore be more specific as a training and selection tool. The current study demonstrated a very high association between the force profiles from the Rowperfect ergometer and on-water indicating that this ergometer replicated the patterns of on-water sculling. In addition, the body positions at the catch and finish for both styles of rowing closely resemble each other. A more efficient transfer of learning may therefore apply across the two forms of rowing as they demonstrate similar kinetic andkinematic elements during the performance of the skill. These findings support the use of dynamic ergometers such as the Rowperfect as a more specific training regime and crew selection tool.