Hi

Read this Portuguese / english manual

http://www.titanlux.com/docs/Guia%20de%20Pintado%20Yate.pdf

There is a antifouling chemical remover.

It works realy fine...

You just paint it over your antifouling wait 30 mints and jetwash with water.

Repeat the process if necessary.

International Products also has this

http://www.mailspeedmarine.com/antifouling/international-paints/interstrip-antifouling-remover-12360-1236189.bhtml

Manual:

http://www.mailspeedmarine.com/photo/10531889/aaecaca46c809eb7cc6cfdf67410e264/International%20paints%20painting%20and%20product%20guide.pdf

Best regards

Jose