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| Antifouling is the most frequent painting job carried out by boat owners and one of the most important. In this section we explain what the challenge is, why you should antifoul and the technology behind the paint.
What is fouling? There are three different types of fouling, each of which has its own characteristics, likes and dislikes. | ANIMALS
Animal fouling, such as barnacles, release millions upon millions of microscopic 'juvenile' barnacle larvae into the water which move around in the currents. Because the nutrients they need to grow into fully developed adults are suspended in water, they have difficulty in feeding and therefore look for static objects. As most boats remain static for 90% of their time afloat, they offer extremely suitable feeding grounds for all types of fouling. WEED
Weed comes in a variety of forms. Static objects will attract common seaweeds, many of which will simply fall off when a boat hull begins to travel through the water. However, some weeds, such as Brown weed, are more resilient and can withstand quite high speeds through the water. SLIME
Slime is the third form of fouling and presents a formidable challenge to the antifouling chemist. Slime is caused by billions of single celled algae which produce a syrupy type medium in which to settle. In common with many types of fouling, once established they provide an ideal settling ground for more algae. Hence, coatings of slime can grow quite thickly on a surface and this remains on the hull as it moves through the water. | | | | | |
Why does fouling vary so much between areas? Different water qualities and temperatures produce different types and breeds of fouling. The differences can be quite dramatic in even a small area, often due to outfalls, pollution, inflows from rivers and streams, and the speed of flow of the water - even shading from cliffs, trees and buildings that reduce sunlight. |
| | | | Getting the right colour All antifoulings change colour when they are immersed, so don't be surprised when you have finished the job and the colour is not as you had hoped from the colour chart. The true colour will establish itself a short time after the boat has been launched. This change in colour is caused by copper compounds within the antifouling which are difficult to mask with colour pigments. Along the waterline you will often find that the antifouling looks dirty and can even turn green. This is mainly due to the reaction of the paint with oxygen, forming green copper oxide. Interspeed 2000 used on the waterline will reduce this sometimes unsightly problem, though periodical cleaning may be needed to prevent fouling growth in high fouling areas. When applying a boot-topping, antifouling should not be applied over a topside finish. Propellers, outboards and sterndrives Most of these areas are either constructed of aluminium or in the case of propellers and sterngear, bronze. There are no reaction problems in using copper containing products on bronze. However, it is important to ensure good preparation in order that the antifouling adheres during the period of use. Aluminium components such as propellors, stern drive units and outdrive units cannot be painted with some copper containing antifoulings so it is important to check that you are using the correct product. In the case of propellors be they aluminium or bronze, the high speeds and turbulence developed dictate that only hard antifoulings should be used after suitable preparation and priming. | ANTIFOULING THAT IS NOT CONTINUALLY IMMERSED MAY DISPLAY VARIATIONS IN COLOUR DEPENDING ON THE DEGREE OF IMMERSION AND THE LEVEL OF SUNLIGHT TO WHICH IT IS EXPOSED |
This is one of the biggest concerns when looking to change antifouling. Please refer to the chart on the next page to help you choose the right antifouling. |
COMPATIBILITY CHART | CHOSEN ANTIFOULING | MICRON CSC | COPPERCOAT | CRUISER SUPERIOR | INTERSPEED 2000 | LONGLIFE | VC OFFSHORE | BOTTOMKOTE | PREVIOUS ANTIFOULING (IN GOOD CONDITION) | MICRON CSC | D | D | D | D | D | R | D | COPPERCOAT | D | D | D | D | D | R | D | CRUISER SUPERIOR | D | D | D | D | D | R | R | INTERSPEED 2000 | D | D | D | D | D | D | D | LONGLIFE | D | D | D | D | D | D | D | VC OFFSHORE | D | D | D | D | D | D | D | BOTTOMKOTE | H | H | H | R | R | R | D | ANY ANTIFOULING IN POOR CONDITION | R | R | R | R | R | R | R |
D - Apply the chosen antifouling directly after a light wet sand, wash with fresh water and allow to dry. | H - Apply the chosen antifouling directly after a heavy wet sanding with 80 grit wet and dry paper followed by a fresh water wash and allow to dry. | R - Remove the antifouling totally. | | TO PREVENT REACTION, DO NOT APPLY ANTIFOULINGS OVER TOPSIDE FINISHES |
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| Preparation and priming before antifouling | |
Serious detachment is caused by incompatibility or not following immersion guidelines. | | The condition of any existing coating is important in order to provide a sound surface for the new antifouling. 1. If the antifouling is of known compatibility (see the Compatibility Chart ) check the condition of the existing painted surface. Remove any loose, flaking areas with a scraper. Rinse with fresh water and allow to dry before applying the new antifouling direct. 2. If the previous coating is in poor condition it is advisable to remove it by wet sanding. Remember, dry sanding is dangerous due to the toxic dust which it forms. Then follow the preparation and priming for bare substrates. 3. If the old antifouling is of unknown origin or you are concerned about compatibility, we advise you to remove the antifouling or contact the International Epiglass Helpline. 4. If the boat is new, or touch up priming is needed on the bare substrate, follow the advice in preparation and priming for bare substrates for wood, steel, glass fibre or aluminium as appropriate. | HINT SEE SURFACE AREA OF YOUR BOAT GUIDE AT THE BACK OF THIS MANUAL TO CALCULATE THE QUANTITY OF ANTIFOULING TO USE. |
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| Applying antifouling | | Application of antifoulings is not a difficult task but some points need to be understood in order to make the job as easy as possible and to get the best performance. | REMEMBER THE TRUE COLOUR WILL DEVELOP THREE OR FOUR WEEKS AFTER IMMERSION. |
2. Common application methods include roller or brush. Spray application can be undertaken, but requires specialist equipment. 3. For roller application, a short mohair roller of either radiator or larger size is usually the best, unless it is stated otherwise on the can. 4. For brush application, it is advisable to use a large width brush. The finish achieved is unlikely to be as good as a topside paint, therefore, the type of brush used is not critical. 5. It is very important to apply the correct thickness of antifouling even if it means putting on an extra coat. Different people apply products at different thicknesses, so take care to apply all of the paint calculated using the chart at the back of this manual. The recommended thickness is normally achieved by the application of two coats. 6. We advise you to apply an extra coat to the leading and trailing edges, waterline, keel and rudder. These are all areas of high turbulence where the antifouling tends to wear faster. This applies to both eroding and hard types. | IMPORTANT
ALWAYS USE THE SPECIFIED AMOUNT OF ANTIFOULING. UNDER-APPLICATION CAN RESULT IN PREMATURE FOULING, AND COSTLY MID-SEASON HAUL OUT. |
8. Antifouling Thinner #3 is suitable as a thinner and equipment cleaner. Thinning is not advised, but up to 10% may be added to aid application in very hot or windy conditions. We also advise that all equipment should be washed out immediately after use. | HINT
USE A FLAT BLADED KNIFE, E.G. PALLET KNIFE, OR PIECE OF WOOD FOR STIRRING. |
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