We see a lot of problems with boats that come in for service. The photo above shows some corrosion found on a boat. Our best guess scenario is that copper based bottom paint was used on metal, causing the massive corrosion. This sort of problem needs attention before the metal completely corrodes away to the point where it is unsafe. To rectify the first step is to remove all old paint and corrosion and take the area down to bare metal. This will not be an easy task because at this point the corrosion has caused deep pitting in the metal. We will need to make sure all traces of copper paint have been removed before coating with primer. Sometimes we resort to sand blasting if the area allows it. If not, we need to use elbow grease to clean it up.
After getting the area clean, we will need to prime properly. I have done quite a bit of research to find the right products for the job and we have whittled it down to two products which have similar properties – Interlux’s Trilux and Epaint – a relatively new product in the marine market, but one we have been using on outdrives for 2 years with excellent results.
Of course neither of these products will be effectively without the proper priming and proper thickness. All the information is readily available on line, but in the hands of the inexperienced having the right products doesn’t do much good. We make sure that the bottom painting crew knows what product gets applied and that they have all the information available to do the job right.
The same holds true when switching bottom paints. Some paints just aren’t compatible. You should have in your records what kind of bottom paint is on your boat and supply the boatyard with that information. If you have any doubts, you should remove old bottom paint and reprime the boat to progress with the bottom paint you want to use.