Zt, I have to giggle on this one, and your response is why I avoid this drill. If you need to use this many words to describe what it does, there’s really no point to the drill. I would suggest change the name from UNCO to SAP, “single arm pull”, that’s what it is. This is what we want to avoid treating high and low side arms as independent departments, it’s all connected. The UNCO/SAP is like a one legged elephant (OLE?), if there were any benefit at all it’s removed with the problems, confusion, frustration it creates, especially for the novice. It may look cool to do with fins, but if cool has no specific point, it’s not cool and is counterproductive. I do kinda like OLE’ though, it’s catchy (pun intended) and describes it much better the UNCO :-). I suggest trying the TI “Slot to Skate”, this is the whole body connected move you are seeking, high and low side arms connected with hips, using weight of high side arm to rotate body and not pulling to rotate. Swimmers discover the complexities of the “catch” happens naturally too. Simple, effective, easy to execute, and is rehearsing the most important whole body movment and switch that quickly integrates into freestyle.
Re: Single arm fly. It’s not about rotation, it’s about releasing the arm away from body with relaxed shoulder and slicing in naturally while still holding your edge. Simple, precise and effective. You’ll never see the body sink since the weight and momentum of the swinging arm is rebalancing the vessel and pulling the body forward *without* the impulse to pull from low side. This is aimed at experienced swimmers that have no idea they’ve relied on the pulling arm for stability and human terrestrial movements triggering imbalance.
Maybe I missed it in the noise, but still didn’t catch what type of engineering you are in, where you from (Perth?), where you coach, your favorite swimming pool or areas, films of you swimming/drilling, etc. A little bio helps give us context of your background and love of swimming and coaching.