Sorry should've elaborated. I know there are UWB RFID tags in NFL player shoulder pads. I was also under the impression that the ball itself is tracked. Is this not the case?
I imagine a football is easier to sneak sensors into than a cricket ball though. Restrictions of the ball itself. Which I realize now that you call it out.
Out of curiosity, could you link to some of the rowing sensors? A quick google brings up http://www.smartoar.com/ i'd be interested in seeing what there is in the way of cheap options you've used.