What you need to know about bottom paint

 

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ANTI FOUL IS WEARING ME THIN   What do you need to know about bottom paint



 Anti Foul/ Bottom Paint: One of the products we apply to our power boats that we know will just wear off and we will have to recoat it again and again. So what does bottom paint do, what makes it work and how long should it last? These are all questions I have heard over the years. Bottom paint is used for the reason it was developed (preventing growth by wearing a thin layer off every time you run the boat, it contains a high concentration of copper to inhibit growth) it is also used to hide a world of sins (easy application to hide patch work and repairs). Boats which are to big to trailer are expected to be bottom painted due to the fact that they are in the water at all times, except for a winter season, and out for repair work. 

When do you need to bottom paint a boat?. Well the first thing that must be considered is the amount of time you will be in the water. Next is the water that you intend to keep your boat in. A boat should only be painted if it is going to live in the water full time.

 If you bottom paint a boat or buy a boat that is bottom painted and you are going to keep the boat on a trailer, the paint is a waste of time and money. As a matter of fact you will end up recoating just to keep the boat looking good, not for reduced growth. Which is what bottom paint is designed to do. If you allow the bottom paint to dry out which only takes a couple of months it is no longer effective and will start to come off in pieces. If you are shopping for a boat and it lives on a trailer and already has bottom paint there could be another reason for the bottom paint to be on the hull. Bottom damage is expensive to repair and repair technicians will offer a bottom paint finish to save money and time rather than trying to repair the hull to a factory finish with gel coat. So be care full with bottom painted hulls on trailer boats do your best to get the history don't rely on a survey. You will notice that trailer boats with bottom paint usually have paint all over the bunks, rollers and trailer. This is a sign that the owner has been repainting the boat on the trailer, so there is likely next to no paint under the bunks. Unless you are in heavy growth water such as salt or unusual fresh water conditions you really need to calculate the cost of a bottom paint program over the time you own the boat versus cleaning the bottom of the boat regularly. The amount of growth without paint is directly related to the hours of operation a boat that sees a lot of hours will see a small amount of bottom growth if any at all.

I have bottom painted boats as small as 15 foot due to the fact that the boat was being kept in the salt water all year round. For boats that are in the water all the season and do not see many running hours bottom paint will save you the growth problem that will occur from lack of movement, even in fresh water. Bottom paint will not stop growth, it simply allows the growth to come off under normal boat operation. This only works if you use the boat regularly if it sits all season and you take the boat for a late season run you will find when you haul the boat that you will still have a lot of growth on the bottom of the hull.

BOTTOM PAINT TIPS

• Do not try to sand and remove old bottom paint it may contain arsenic this would be pre 1990
• Do not roll coats of anti foul just because of discoloration you will build up massive thickness that is horrible to try to make right
• Bottom paint does not have to be applied in super thick coats to work
• Bottom paint will rob the boat of speed
• Select the right product for the job, there are anti fouls for hulls, running gear and transducers do not paint every thing with one paint.
• Do not paint running gear unless you purchase the correct primer and paint
• They make bottom paint with tin instead of copper content for aluminum boats and drives.
• Do not paint the copper based anti foul up to the drives or tabs leave a gap the copper bottom paint and the metals in the drive and other components will cause electrolysis (corrosion) on the transom plates and drives.
• Do not paint over anodes this makes them useless.
• If you are repainting a hull or are starting new it is a good idea to have the first coat a different color than the top coat, first coat blue the rest black this way as the bottom paint wears you can see when and where you need to recoat.
• Do not feel that you need to repaint the whole hull you can touch up for many seasons before recoating the whole hull.
• It is a rare occasion in fresh water to need to paint the running gear.
• Be sure your bottom paint line allows for two inches (higher) at the water line this will prevent those nasty water line stains
• If you have to raise the bottom paint line and you have not added any accessories to the boat , there is a reason. Boats will pick up weight over the years this is natural, however a sudden change is a sign that you are probably holding trapped water some were. If you use a travel lift to haul out get the weight of the boat every year at haul out and launch, keep track of these numbers and you will know if the boat is gaining weight.
•  If you add accessories such as swim platforms, generators, radar arches you will have to adjust the bottom paint line.
• Do not paint to a list to the port or starboard correct the load in the boat first, get ride of the list.
• Try not to paint to far above the water line it looks okay for a week or so then you will see the paint above the line start to get green as the copper in the paint ages.

Several attempts have been made to create a anti foul that will last the life of the boat without recoating, as well as a coating that can be applied in the mold at the time of construction. The life time anti foul was very close to working but it is super expensive and messy to apply. I did a proto type of this product once and wasn't a fan of the overall cost versus end product. You would have to own the boat over 15 years and need to re anti foul every year to make the system worth while. (The life time system does eliminate the need for a barrier coat).

If you use a lift or keep your boat in a high and dry facility you can remove bottom paint. It is a back breaking job, dealers have done this to 320 and 340 boats that have been sold new and will not live in the water full time. I have seen many products sold over the years that promise to make the hull so slippery that growth will not stick, I have never seen one that works that well. Generally due to the fact that the boats that receive these coating still do not see the amount of running time to make these coatings really effective.

Bottom Paint is the only real sensible option to prevent growth that is available to boaters. Bottom paint comes in many different brands and speeds. The speed terminology refers to the hull speed. Soft paints that sloff off at low speed will not work well on power boats and visa versa. Be sure you explain to your supplier the boat that the bottom coat will be applied to and the hull speed you run most of your time at. This way you get the best paint and value for your money. Bottom paint is available in blue, green, red and black (and other crazy colors). I recommend you pick any color you want as long as its black. It works the best, most colors are soft and only look good twice a year when you put it on new and after the boat is pressure washed at the end of the year. If you own a power boat and when the hull is pressure washed you see the bottom paint running all over the ground the paint is probably to soft and wearing of the hull to fast.

 Hull Preparation:

•  Never had bottom paint- The standard hull preparation for bottom paint is to sand the gel coat surface remove all the shine, remove the dust and apply at least two coats of your favorite brand of paint
• Never had bottom paint- The option I choose is the sand less primer system, you must buy the same brand paint as the sand less primer, I like this option better because you are not cutting through the resin rich gel surface.
• Recoating- If you are sticking with the same paint, Start by giving the hull from the water line down a really complete pressure wash try to remove what ever will come off (time spent here will save time later), then you sand down the edges of chips and flaked areas, mask off your line and items not to be painted. Start your re coating by covering the bare areas first and then coat the whole hull. This will keep the material build up fairly even over the hull.
• Annual clean up- This usually entails a few touch ups and at the very most a belly band, this is strip re coated around the water line a foot or so wide that's it. all you need here is a clean dry surface that's it.
• To find your water line you may need to float the boat if you are not full of water and fuel don't worry just add an inch. I did this on all new bottom paint jobs until I had a book with the various models to refer to, and even then one or two would throw a curve ball and be different.

A SPRING START UP TIP FOR YOU:
 
DO NOT RE COAT WITH NEW BOTTOM PAINT BEFORE YOU POLISH  THE HULL

Like any other service or maintenance job we do to our boats buying the right materials and working in the right conditions will pay off . The finished job will last longer and provide better value for the money spent. Be sure to inform your supplier of your needs and ask them the expected life of the bottom paint you are purchasing, some bottom paints come with a limited warranty.

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