Bottom paint is essential for a boat, and it helps the boat so much. Here are some things you need to know before painting your boat bottom.
Bottom paint for a boat is used to stop the growth of algae, barnacles, and weeds below the waterline of the boat. The paint contains chemicals (biocide and copper) in it, and it starts slowly releasing the copper overtime to stop the growth of algae, barnacles, and weeds on the boat bottom.
To restrict or stop the growth of algae, barnacles, and weeds or any micro-organisms are the main reason for using bottom paint for a boat. If algae, barnacles, and weeds don’t grow on the boat bottom (boat hull), then there is no need for bottom paint at all.
Bottom paint for a boat is essential for the people who keep their boats in the water for a long time (maybe for months or full season). If you don’t keep your boat in the water for a long time, then you don’t need bottom paint for a boat at all.
Bottom paint for a boat is not needed for the people who remove the boat out of the water every time after boating or for the people who keep the boat in the boat stand near the marina after boating. If you remove the boat out of the water every time after boating, then you don’t need bottom paint for a boat at all.
For the people who remove the boat out of the water every time after boating, just spending 10 or 15 minutes to clean the boat with a pressure washer or take a brush and cleaning the boat is sufficient, those boats don’t need bottom paint at all.
But, many people won’t prefer to paint their boats because the anti-fouling paint causes some problems (go down a little bit to see the effects of bottom paint). So, think about all those effects of the bottom paint before painting the boat bottom.
Check my article on How long you can leave the boat in the water (opens in a new tab) to know how long can you leave the boat in the water without bottom paint and growth prevention tips as well.
Can you use regular paint (oil-based) on a boat?
Regular paints (oil-based) are not used for painting the boat bottom. Regular paints can’t stop the growth of algae, barnacles, and weeds at the boat bottom. You need to use antifouling paints or marine paints to stop the growth of any algae, barnacles, or organisms on the boat bottom.
You can use regular oil-based paints for painting the boat above the waterline. But, you can’t use those paints for the painting below the waterline. Even for the painting the boat above the waterline, there are some special paints, which have a high-performance coating UV resistance, color retention, flexibility, and durability (source).
Anti-fouling paint has chemicals in it, and it has biocide and copper. If you paint your boat with anti-fouling paint, then the copper slowly releases (or leaches) over time, which helps to prevent the growth of any micro-organisms, algae, barnacles, and weeds on the boat bottom.
Overall, you can’t use regular oil-based paints for boat bottom; however, oil-based paints can be used to paint above the waterline of the boat. You need to use anti-fouling paint for painting the boat bottoms because this helps to stop or prevent the growth of algae, barnacles, weeds, and any micro-organisms on the boat bottom (source).
Types of bottom paints or anti-fouling paints
There are two types of bottom paints for a boat, which are ablative paint and hard bottom paint. Ablative paints will wear off quickly than hard bottom paint because ablative paints are soft polishing paints so, they wear off soon than hard bottom paint.
Ablative paints wear off over time. Water flow will wear the paint away over time, causing the biocide (copper) to leach out. The faster your boat speed, the faster the bottom paint wears off, and the more often you must repaint it.
Hard bottom paints consist of a tough epoxy coating. With these products, the paint doesn’t wear off quickly, but the biocide (copper) does. Meaning you’ll end up with no biocide, and you’ll have to repaint the boat bottom.
Do all boats need bottom paints?
All boats don’t need bottom paints; boats that stay in water for a long time need bottom paint because algae can grow quickly on the boat if they stay in the water for a long time. Boats that are removed out of the water after every use or frequently don’t need bottom paint at all.
As I discussed earlier, for the people who remove the boat out of the water every time after boating, just spending 10 or 15 minutes to clean the boat with a pressure washer or take a brush and cleaning the boat is sufficient, those boats don’t need bottom paint at all.
Check my article on the Effects of saltwater on boats (opens in a new tab) to know how saltwater affects the bottom paint on the boat and prevention tips as well.
Effects of using anti-fouling paint or boat bottom paint
There are some effects of using bottom paint or anti-fouling paint on the boat. Here are some effects of using anti-fouling paint or bottom paint for a boat (source).
- Anti-fouling paint or bottom paint of a boat may harm aquatic life.
- Thick layers of anti-fouling paint may increase your boat weight, and eventually, it may increase your gas consumption as well.
- You need to do extra maintenance to the boat hull, and sometimes DIY may be dangerous.
These are the primary concerns about painting your boat bottom with anti-fouling paint. So, think about those problems before painting your boat bottom unnecessarily.
1. Anti-fouling paint or bottom paint of a boat may harm aquatic life
Bottom paint or anti-fouling paint, which is painted to the boat hull, will release (or leaches) copper over time to reduce the growth of algae, barnacles, or any micro-organisms. Since the paint is releasing the copper overtime, that copper may affect the aquatic life in the water.
Most bottom paints contain copper, and by the end of the day, all the copper from the paint will be leached out. This leaching happens at an estimated rate of two pounds of copper per year for a 30 feet boat. Now, imagine a marina with 100’s of vessels, which can cause problems to the aquatic life in the water.
If there are 100 boats (each of 30 feet in length) in the marine and every boat will release 2 pounds of copper into the water in a year, and all the boats combined will release 200 pounds of copper into the water in a year, which will cause damage to the aquatic life.
2. Thick layers of anti-fouling paint may increase your boat weight, and eventually, it may increase your gas consumption as well
Although it may sound weird (how the paint will increase the boat weight), yes, it increases your boat weight.
If you are painting the boat bottom a couple of times each year, and if you don’t use the boat frequently, then those thick layers may eventually increase the boat weight. Although there won’t be any significant increase in weight, and most probably, you may not be able to differentiate it at all.
There will be only a less increase in weight, not a significant difference. For a 30 feet boat, it will take around 1 – 2 gallons of paint for two coatings. Like that, if you do it for 3 or 4 times and if you didn’t scrub the boat properly before repainting it, then it may increase 50 pounds (roughly) weight overall for 3 or 4 times.
And, again, if the weight of the boat increases, then the boat displaces more water space in the water, then the boat requires more power to push that extra water out of its way. So, the gas consumption of the boat increases if the weight of the boat increases.
3. You need to do extra maintenance to the boat hull, and sometimes DIY may be dangerous
Bottom painting a boat is not a simple task, it consumes your time if you are doing it yourself, and it consumes more money if you are giving that job to others (boatyards).
Painting is one work; after that maintaining it and repainting it is another work. While repainting the paint, you need to scrap the hull to remove the old paint. This whole process is a cycle process. Once, if you apply the paint, over time, the paint wears off, and again you need to repaint the boat.
Once the paint wears off, again, you need to repaint it; otherwise, algae, barnacles, or micro-organisms may start growing, and it may not look good on the boat—every time you need to spend money on it. Again, if you decided to give the job to the boatyards, then it may become expensive.
Nowadays, many states are banning boat owners from DIY jobs, and many boatyards are also not accepting it to a DIY job due to the risk factors involved in it. Giving the painting work to boatyards means it takes more money and expensive.
Overall, maintenance is a big problem, and it is expensive as well. Painting the boat by yourself is dangerous as well. So, you need to do extra maintenance to the boat hull, and sometimes DIY may be hazardous if you don’t know how to do it properly.
Ket takeaways
If you keep the boat in the water for a long time, then you need to paint your boat bottom. Otherwise, algae, barnacles, weeds, and any micro-organisms will grow on the boat hull. Then it will be a big mess for you and your boat as well.
Bottom paint is necessary for those boats. If you don’t keep it in the water for a long time or if you remove the boat out the water frequently, then just spending 10 or 15 minutes to clean the boat with a pressure washer or take a brush and cleaning the boat is sufficient, those boats don’t need bottom paint at all.
If you are like that, then don’t paint the bottom unnecessarily, you can save money and the aquatic life as well. So, think about all those effects of the bottom paint before painting the boat bottom (except if you keep the boat for a long time in the water, then you need to bottom paint it).