Rowing against the Tide

I have been trying to do Crossfit Endurance workouts on my "rest days".  I have this goal to break 1:30 in the 500m row and I cant seem to make any progress towards.   On the other hand my wife as part of her warm-up 500m row absolutely nails it and lands in 3rd on the leader board.   I hate to say that some people are natural rowers, i prefer to say that there body types probably lend to them being more efficient.   She is long and tall for a woman and i am short and stocky and i will leave it at that.