When waves run into water moving in the opposite direction, they are slowed, just as if they were approaching a beach. Wave length becomes shorter, wave height higher, and they may break. A good (bad) example of this is an ebb current flowing out of Raccoon Strait into waves coming in from the Golden Gate. Good rough water training, if that’s what you want.
* While there is nothing to adjust from row to row on the WaterRower, it is possible to increase or decrease the level of resistance by changing how much water you put in the drum. The monitor is pre-calibrated to match 17 liters of water, but you can change that if you want. More than 17 liters = more resistance, up to the max fill line. This is not something you'll want to change frequently, it's more of a set-it-and-forget-it thing.

In sweep or sweep-oar rowing, each rower has one oar, held with both hands. This is generally done in pairs, fours, and eights. In some regions of the world, each rower in a sweep boat is referred to either as port or starboard, depending on which side of the boat the rower's oar extends to. In other regions, the port side is referred to as stroke side, and the starboard side as bow side; this applies even if the stroke oarsman is rowing on bow side and/or the bow oarsman on stroke side.