I'm a rower as well. I was using the Galaxy watch till now. I was bringing my phone in the boat just to track the speed. I bought the Galaxy Watch 4 Classic hoping that the Wear OS will solve the issue. There was a brief moment of joy when I saw on the watch the option to add activity from the phone and I was able to add the rowing (outdoors) to the watch. Unfortunately, my joy lasted only one training session. Although the activity was added to the watch, the GPS is not used to track distance and speed if you don't get the phone with you in the boat. Then, I've installed Google Fit on the watch and I can track my rowing with GPS. So, it is not hardware limitation, but pure software one. I'm moving to using Google Fit although I really like the Samsung Health app. The next step will be to buy a Garmin watch and who knows, maybe stop buying Samsung phones. There is absolutely no point for me to stay in this ecosystem as it is not suitable for anyone else except casual runners, walkers and cyclers. When I say "casual" I don't mean the effort. I mean the information tracked. I'm sure the watch is capable of tracking much more than just steps. I'm sure it can track rowing strokes and some specific movements for other sports. If Samsung were clever they would not have the rowing on the phone, but only on the watch as it makes much more sense to row with a water resistant device securely attached to your hand than putting a $1000+ phone that cannot swim in a boat 
