In the Chesapeake, they essentially are going to make cleaning them in the water a no-no. You really can't get a bottom cleaned with ablative paint without creating a plum UNLESS you clean the bottom VERY GENTLY and do it VERY OFTEN to keep the growth to a minimum.

If you have a semi-hard bottom, then you don't creat a "plume".

I avoided doing this for over a while. Finally, this year I cleaned off the old paint with a soda blast and put VC Offshore on. It was expensive to get the soda blasting done -- but you have to clean the old stuff off before you apply the new paint.