In process of preparing newly purchased Oday 22 for launching in a few weeks. My aim is to apply new coat of anti fouling paint. Guy at local West Marine pointed out it is very important to match paint type with previous application. My hull seems to be in excellent shape. Very smooth with little to no build up of foreign material, algae, barnacles etc. applying a light sanding results in a fine black almost powdery dust but leaving a hard coppery colored surface. West Marine thinks from that description its VC17. How can I tell. Any ideas how to identify the type of paint?