A couple of months ago, we wrote about using the erg not just for training but also for technique. With less need to focus on balance and timing, more attention can be given to other areas. First though, you need to figure out what needs to be changed.
If you don't already have a good idea, look to video or photos of you. I find it particularly helpful to see myself when I'm racing and thinking more about power then technique. What skills am I able to maintain and what goes by the wayside?
I find I'm constantly working on three technical areas (after 40+ years of rowing!) - the catch, my movement out of bow, and hanging through the drive. That pretty much covers the whole stroke! I was disappointed to see in many race photos this past year that I was starting to use my arms long before my legs were down. In watching a lot of video and photos of Olympians and World Champions, I've noticed that almost to a person their legs are down before they begin to break their arms. It makes sense. The legs are so much stronger than the arms, especially for women.
You will see the same in big boats
My favorite drill for trying to delay the arms is to row legs and body, no arms. I sometimes hesitate to suggest it as many people then try to lock their elbows, cutting off the all-important connection to the lat muscles, and making the finish too harsh and abrupt. So start easy with the drill, with little to no power and keep the elbows soft.
Make sure you're feeling a connection to your lats and not your traps, and try to finish the stroke without using the arms. Slowly and gradually build the pressure so you can feel the surge of power with the legs and back at what is now your finish position. After ten strokes of feeling this, add the arms back in but not until the point where you were finishing the stroke during the drill.
Getting someone to video you while you're going through the drill can be very helpful, as is simply having a mirror next to the erg. Be mindful when you're erging and you can learn new skills to take with you when you get back on the water.
and in every boat class