One thing you might try twice each week would be Tabata rows. 20 flat out, 10sec "active rest" or row really slow, eight rounds, NO BREAKS. ENSURE you are really warm before you try this.
Learning to do a barbell power clean would help also, I believe, doing low reps for strength first and then doing occasional "met-con" workouts using a light weight, IE, 75-115lb
35 minutes on the Concept 2:
4 minute warm up and then did your recommended Tabata workout. 20 seconds max and 10 seconds rest. Did 8 sets then decided to do 2 more. Total of 10. 20 second rows were hitting 85 meters.
Went to 30 minutes with intervals and finished up with a 5 minute slow down for a total of 35minutes.
