over the years, I have tried bottom paint on my props with inconclusive results. 2 years ago I painted one lobe on each prop and could see no difference in teh amount of barnacle growth when compared to the unpainted lobes. So last year, on April 14, I hauled and chose to leave the props unpainted. By the end of June, i had so much barnacle growth that it overloaded boat engines. When i got to warmer water, I manually removed the barnacles, while in the water. By April again, the growth is so thick that the engines are blowing black smoke and won't get up to full speed.
I attribute this dramatic change from other years to a change of location. from April to October, my boat is now moored at Saltspring Island, from October to April, in Vancouver's Coal Harbour. The salinity of the water and its health for barnacles is dramatically different, so a different regime is called for. I haul again on June 1, so this time I will be painting the props.