adjusting span=adjusting oars as well?

[Steven M-M]

Diesel -- I'm with KiwiC. Even within the extreme end of normal for rowing, pinching is not a problem. As we know from a poorly matched pair or sculling with one blade you can push the bow one way or the other because of the sideways force perpendicular to the blade. When we think about length at the catch, we should focus on effective length: what is the catch angle when the blade is adequately covered to do work. So a good reach is important but so is Sul's advice: "quick in, quick on."

A big take away from John G's theoretical and empirical analysis of one stroke by one of the S brothers is wonderfully old school: once loaded (bend the oar) the blade is comparably efficient/inefficient across all phases of the stroke, ~70%. There is no more and no less efficient phase of the stroke.

[beagle]

When we think about length at the catch, we should focus on effective length: what is the catch angle when the blade is adequately covered to do work.

center of the blade being in the water (not full coverage) is enough to provide propulsive force, which overcomes drag and starts the boat-rower system moving forward, and full coverage provides full propulsive force