The bane of boaters is fouled running gear. We have seen owners who use bottom paint to try to fight this, but always with limited results.
Over the last couple of years, we have experimented with a product called Prop Speed with good results. This can be applied to props, shafts and even struts. Although expensive, about $150 to do two large props, it does seem to work as advertised. This morning I just read about a new player in this market. Petit has announced a new product called Prop-Kote which also has the same characteristics as the Prop Speed. Both work by leaving a surface that is too slick for growth to stick to. We will be comparing this product against the Prop Speed to see which gives better results.