In an effort to begin training for Head Races (3 mi), here is a nice intro to some longer rowing pieces. It will provide good low rate intervals with periodic elevation in heart rate with short, high rate power.
Alternate between 22 and 24 strokes per minute for each 500 meter. 22 (5K +8), and 24 (5K +6). At the beginning of each stroke change, take 5 strokes at 28 (5K pace or better) and then settle it to the given stroke of 22 or 24.
After 6K work rest 3 minutes then,
10 strokes ON, 10 strokes OFF at 28 FULL POWER x 5
Take nice long powerful strokes with quickness
cool down 5 min and stretch