IMHO only the pic (numbered 5) is anywhere close to being able to present.
Sports: IMHO you want to see the face, clearly, you also want to see the equipment, in your sequence you only really see the canoe I'm one shot, and your rower is facing the wrong way.
Poise: excitement, control, focused mind, skill, adrenaline, mastery, power, not present here, the guy looks totally overwhelmed.
I think for these shots to have worked better you would need to have been more elevated looking down, maybe that way see more of the craft and the shape of the course. Maybe there was a more photo friendly point somewhere else along the course, if it absolutely had to be at this point then maybe position your self so you were face on as he exits the turn and down course.
The key to good sporting shots IMHO is to arrive early, walk the course during warm ups, have a map, and just work out what's going to give you a good clear shot (the face is all important) at a point of action.
I know that because of the terrain, cordons safety etc this chosen sport it more restrictive than most.
Can I ask, did you have a press pass or were you in a stand etc?
I just feel although there is plenty of action, there isn't great composition, or dynamism, there is no empathy or connection to the rower because you don't get to see his eyes clearly.
Focus, check, exposure, check, drama, check, just another couple of things to work on, if you are going to present then yours need to be as good as at least, if not substantially better than anybody else's.
I've tried to be fair and give honest constructive advice, if asked for an opinion, that's what I'll always do. I look forward to seeing what you get from the next event.