Zinc Chromate is not available in NY, and hasn't been for 25+ years.
What I use is Rustoleum Acid Etching Primer, or NAPA Acid Etching Primer.
I use brass wire wheels.
My "Toy Boat" is really not a dinghy. It's a semi V Sea Nymph 14R, which has a deep freeboard. It used to handle 2 fat...