2 Sets

1000m Row @ < 24spm (strokes per minute)
750m Row @ 24-28spm
500m Row @ 26-30spm
250m Row @ > 30spm

Rest 2:00 b/t intervals
Rest 6:00 b/t sets

Pace. Start the first interval at a low rate (<24spm) but challenging pace for the 1km piece. Then increase your rate to moderate for the 750m (24-28spm) and finally increase to a higher rate for the 500m (26-30spm) and 250m (>30spm).