As much as rowing seems like an exercise in the arm, most of the strength for each stroke really comes from the leg push. It's also important to note that it's not just how many strokes a minute you can do, but about the quality of each stroke and how much space you can create for each stroke.
Round 1:
1000 meter Row
1 mile Assault Air Bike
200 Single-Unders
Round 2:
750 meter Row
0.8 mile Assault Air Bike
150 Single-Unders
Round 3:
500 meter Row
0.6 mile Assault Air Bike
100 Single-Unders
Round 4:
250 meter Row
0.4 mile Assault Air Bike
50 Single-Unders