Row three 21 minute pieces. Row the first six minutes @ 20 spm. Then five minutes @ 22 spm, four @ 24, three @ 26, two @ 28 and one @ 30. Row for four minutes at light pressure between each piece.
PM3/PM4: B-D-D-D-B-B-A-A-A-A-A-B-B-B-B-E
PM5: B-D-D-B-D-B-B-A-A-A-A-A-B-B-B-B-E