So, how does that look underwater at the different stages of the cycle?
1 reach and setup a slight start of the catch. (same side leg is also setup)
2 start weight on catch. Above water arm is almost at shoulder height moving forward, or about at shoulder height, depending the level of catchup timing. recovering shoulder is rotated up, while the low arm has to stay outsinde the centerline with an upward rotated elbow. this together requires the shoulderblades to be pressed together.
3 peak weight on catch.
At this point the mass center of the weight above water is more or less at he same level as the catching arm, so the weight is pessing maximal into the catch. To use that weight effectively in a long stroke its best to have the paddle pointing down at a reasonable angle, otherwise the weight cant be transfered to backward pressure. Low side paddle and high side weight are working at different sides of the body, so together they create a torque that also rotates the body around its axis.
To execute this cycle optimally, you need enough flexibility and shoulder strength/stabilisation.