Of course whether you own a super high performance racing yacht or just a modest fishing boat, there is every likelihood that you are going to have to apply an antifouling coating to the bottom of the boat at some stage.
This is basically true for those boats that are moored or spend considerable time in the water. In these situations it is likely that the boat will require antifouling every 1 to 2 years.
The main aim of bottom paint is to lower the growth of barnacles, algae, and other marine organisms on the underside of the boat that can lower the vessel’s performance.
In years gone by, sheets of thin copper were applied to the hull of the boat to slow the build-up of marine growth. Although this method would now be seen as inefficient by today’s standards, copper-based coatings are still being used in many modern bottom paint products.
Because of increased scrutiny about the environmental effects of copper-based bottom paints, many paint manufacturers are equally bringing out eco-friendly variations that has little or no copper.
Applying bottom paint yourself is not as hard as you may have imagined. Here is an overview of the steps required.
- Choose the correct anti-foulant to match the material being coated. It is vital to check the compatibility of the old paint with the new bottom paint (paint manufacturers will have compatibility charts to guide you). For aluminum hulls or underwater metal, you’ll require a specialised paint to avoid corrosion.
- Prepare the surface well before the painting. This will assist the paint adhere well and provide a longer-lasting coating. If the existing bottom paint is in very critical condition, you may have to remove it using a power sander or paint stripper. In many cases however, this is not needed. Simply clean the hull with either a power-wash or an acid-based bottom cleaner, give the area a good sanding with 80 grit paper, rinse with water and then apply a suitable primer (according to manufacturers instructions).
- Mask off any borders with painter’s masking tape.
- Put the bottom paint according to manufacturer’s instructions. It is recommended avoiding using a sprayer to apply the paint. For ‘Do it yourselfers’, a roller works very well and is surprisingly efficient. Be sure to use the correct roller to match the type of bottom paint being used.
- Stay until the weather is ideal for painting before starting the job. Most manufacturers recommend painting when the temperature is between 60°F / 16°C and 80°F / 27°C with humidity less than 65%.
- Choose the right paint depending on the type of boating you will be doing and the compatibility with existing paint or material being coated.
- Always consult your local boat chandler or marine dealer for advice when choosing your bottom paint.
- Be patient and try not to rush the job. Let plenty of time to complete the process.
- Make the most of the time that the boat is out of the water. Repair any damage to the hull, rudder or keel. Inspect the propeller and outdrives. Inspect anodes and perform out any other maintenance required.