Jan:
I have been coaching rowing for about forty years. I have coached in club, high school, and college ranks and now coach at a small club in Virginia. I have passed the USRA level III exam. I learned 99% of what I know about rowing by doing and coaching. In that I believe that coaching was my most valuable teacher. There were very few coaches when I was young and getting into the sport.
I have used high school age and beyond students for assistant caches for many years and it has always been a very sucessful operation. And these people actually coached crews on the water. A few have eventually gotten some level of certification but most have not. It hasn't changed anything about their value to me in running rowing programs. I am sure that I am not alone in this.
As I am sure you know, certification does not endow a person with coaching skills. It provides persons who know little of rowing who have to run rowing programs with some level of confidence that the person they are speaking to about coaching rowing has some degree of knowledge about the sport. It also provides some background in rowing to people who have only learned one side of the sport. It is a useful tool and I support it, but it is not mandatory to entering into the task of coaching.
Good luck with your efforts and keep using those kids to help. That is where they will learn their sport.
Lloyd Martin
Sandy Run Scullers RC