The above link takes you to the concept 2 website. On the website, there are moving graphics that demonstrate the movement of the blade through the water. In order to truly appreciate how to move a boat, an athlete must understand how the blade moves through the water.
The concept 2 rowing ergometer encourages the idea that the rowing stroke is a two-dimensional movement. In order to move the boat a much more complicated series of movements take place. While the concept 2 machine definitely has earned it’s place in any boathouse, it’s important to remember that an athlete must have a boat moving skill set.
An athlete must appreciate that their movements must be in three dimensions. The rowing stroke involves some lateral pressure on the oarlock in addition to an arc when the rower is pushing the boat along.
The biggest surprise to most athletes, is the fact that the blade actually moves toward the finish line (not straight toward, but at an angle) at the beginning of the drive. This is due to the pivoting of the blade in the oarlock and the forward motion of the boat. Most athletes think that the blade travels away from the finish line at the start of the stroke.
As the stroke progresses, then admittedly there is some movement of the blade away from the finish line.
Study the moving images for a few minutes and you will see how important it is to understand how the blade moves through the water on the drive and what movement(s) an athlete must accomplish in order to keep pressure on the face of blade throughout the entire stroke.