In article , Hanz
wrote:

Has anybody ever put antibiotics into the antifouling paint, like
tetracycline??


Hanz

I used to use oxytetracycline mixed into ablative paint for the areas
adjacent to my propeller shaft, prop strut and feathering prop (hub)
in order to keep the barnacles off. I took veterininary grade
oxytetracycline (pills) , gound it to a fine powder and added to the
paint. Worked well for the few years I used it; but, it leached from
the paint faster than the ablative would erode away and would leave
teeny holes in the paint.
Now I use "Petit Zinc (spay) Barnacle Barrier" ... and that works MUCH
better.