12 Best Bottom Boat Paints in 2023

How to Choose the Best Boat Paint?

Choosing marine paint and learning how to paint the bottom of a boat seems complicated because the options include everything from cheap acrylic house paint-types to military-grade products used on F-16s.

This guide aims to make it easier to get the job done presenting our own experience painting boats with wooden, metal and fiberglass hulls. First you need to get the right paint.

You get what you pay for: if you use the wrong paint, you’ll be repainting again very soon and the bottom of your boat will not be protected, your fuel consumption will increase, and your speed will suffer, etc.

Check our quick review of boat paints we like for different hulls, or check out our guide, How to Paint a Boat at the bottom of the page.

What is Marine Paint?

These paints are antifouling protective coatings, designed to cope with organic pests that attach to the hull of a boat and to withstand seaborne corrosion, sometimes releasing layers of biocides as a boat moves through the water. This guide to bottom boat painting deals strictly with under the waterline.

Whether you’re looking for Jon boat paint or the right kind of coverage to keep your bowrider cruising fast and efficiently, the same procedures are going to be the same.

It’s important to prep the hull of a boat for a long-lasting effect by removing old paint and then all grease from the surface. It’s not always necessary to remove all paint, just the outermost layer. If you’re not racing, it’s good to know that old paint doesn’t add that much weight or drag to a boat for you to bother stripping everything off and painting afresh.

But sometimes it’s necessary and sometimes it’ll give you the chance to do a good job while the boat is hauled up. It could save on fuel costs and if cruising. Most pontoon boats, for example, aren’t performance-based and demand quite a bit of work because of the amount of surface area of different pontoons and difficulty getting at it.

Beyond color, other simple considerations include time, climate (water temperature, freshwater/saltwater) and the boat’s specific surface material or substrate to get the right antifouling bottom paint. The longevity of different paint types is also relevant depending on how many years between dry-dock the boat will see.

If you’re looking to get someone to paint your boat for you, get references when hiring out the task to a jobber without a fast facility. Someone who relies on a reputation anchored to a location is more expensive because of the overheads, but usually more reliable.

How to Paint a Boat: A Brief Description

Things to be aware of when buying marine paint:

What type of paint do you want or need? Be aware that bottom paint or antifouling paint is designed to protect the hull of a boat (sailboats, fishing, waterski, etc.) against the elements and organic

1)Is your boat wooden, metal, or fiberglass? Some wooden boats are covered with fiberglass.

2)Ocean or freshwaters?

3)Multi-season or annually applied?

4)Environmentally friendly or longer-lasting?

5)Surface area – No paint is created the same. The viscosity of paint determines how much surface area a can of boat paint will cover. Find out how much surface you need to paint.

Use this formula (Imperial System with feet) to determine how much paint you need:

Boat length x (Beam + Draft) x 0.6

6)Time: how much time do you have? How many layers of marine paint will you use? Every paint has a drying time and your boat may not need a priming layer.

7)Colors: A different bottom paint primer color is useful to see when the layers have worn down. But often, the primer doesn’t need to be scraped away.

It’s a good idea to know the status of the boat you’re going to paint. Besides knowing the material, it’s a good idea to know the existing paint. Is it hard (like gelcoat or epoxy), semi-ablative or ablative? Knowing this affects the choice of paint you choose and the plan you make.

Antifouling Bottom Paint

Left in the water over a period of time organisms like algae and zebra mussels buildup on the hull of a boat. The area of the boat from just above the waterline and down is exposed to the corrosive impact of the living sea. A clean hull means a quicker boat, easier to maneuver and less thirsty when under motor power.

Antifouling paint minimizes this with a biocide that fights organic growth under the waterline. With ablative paints, the biocide is continuously released as the layers break down. Usually, the biocide is in the pigment rather than the resin, so the progress of degradation can be seen too.

Consider whether you and your boat need an ablative, a modified epoxy, or a thin film. This depends on your labor time, type of water, and the temperature of the climate.

Racing boats will always use hard paints, which are smooth and polishable. Some marine paints come in hybrid versions to offer hard, slick finishes with ablative qualities to last.

An all-season antifouling marine paint with a copolymer ablative profile is good both for colder climates and for sailors wanting to save time. It gradually releases copper biocides, shedding layers rather than disintegrating completely.

Modified epoxy paints are harder and will appeal to boat owners who keep their vessels in the water year-round.

Composite Copper Technology (CCT) is a relatively new formula that has an ablative, slow-releasing biocide profile with much less copper. It’s more environmentally friendly

The environmental choice is a pharmaceutical compound, called Econea, developed to replace copper, meaning no biocides that attack organisms seeking to mate with your hull and no impact on the aquatic system. Rather, Econea was made to disrupt the photosynthesis that plant-life like algae use.

Preparation

No cutting corners here. Whether it’s wood, aluminum, iron, or steel, the surface of the boat needs to be free of grease and any sanding debris before getting painted. Make sure the boat is dry and use a brush to whisk away pesky particles.

Painting a boat, whether it’s non-skid topside paint or on the hull above and below the waterline, is relatively effective and easy these days because of the quality of marine paint available. The industry has made constant improvements to their products making it easier for boat owners to take care of their boats.

90% of the paint job is preparation. Meaning, done right, the actual painting will be quick and effective. If you’re googling how to paint a boat because you’re lost, fret not. As long as the surface is clean (including being sanded) and the coating is evenly spread, it’ll look fine – if not great.

Read Our Guideline for Painting a Boat.

How to get your boat ready for bottom painting:

Removing Tired Antifouling Marine Paint

It’s truly a proper sailor who tells you they enjoy stripping paint from their vessel’s hull. In other words, he’s telling a tall-tale or he’s so enmeshed in sailing that they see even paint-stripping as a labor of love.

When a boat really needs a facelift and the residual paints are layers upon layers of old, clingy paint, paint stripping solutions can save you time and tendonitis.

Maintaining the hull of a boat is tedious and time-consuming, but it is the ultimate sign of respect for a boat and sailing or cruising. Fortunately, proper preparation minimizes the no-joy of it all. And stripping paint is really a no-joy part of getting a boat ready for a season, making it safer and giving it a chance to last a lifetime.

There are different ways to remove paint (often a combination of methods are applied) with time, money and facilities determining which is most practical.

Dry-scraping: the cheapest method

Using scraping tools found that can connect to a vacuum cleaner is a sure-fire way to limit the amount dust, debris and health risks. The Oneida Air System is one easy-to-use tool that will work.

Other handheld models will do too. Find a decent posture and rhythm, use goggles and a mask to avoid inhaling dust particles. A heat gun with sharp implements, hook scrapers mostly, makes the project less tedious. Be careful not to apply too much heat to wooden surfaces, just enough to make paint release its hold.

The Hyde Paint Scraper is a standard tool with a comfortable handle and double-edged blade for pulling and pushing scraping strokes. But plaster trowels and filler knives are readily available at paint shops and can also be used in a pinch.

Angle grinders make dry-scraping go faster. Cheaper power tools can be used and come in handy on other projects. A Black & Decker model  is not the best grinder but works just fine with ample sanding disc pads.

Be careful not to grind away too much on wooden boats and take care not to overheat the surface which needs to retain moisture for the long winter in out of water.

For serious build-up of paint and especially rust, needle scalers are useful tools to completely remove surface encrustations. In many cases, rust patches get battered and fall off taking unwanted paint with it. Dust particle storms are also minimized.

Using tools on any surface of a boat is harder if tools are cared for. Maintaining scrapers will also ensure that blade ends are rounded so as to avoid making gouges in fiberglass or wood substrates.

Using Chemical Bottom Paint Removers

Some of the same procedures for dry-scraping will be used with marine paint stripping products. The difference is time and how much your muscles will protest. Chemical strippers have gotten cheaper, safer and environmentally friendlier.

Smart Strip by Dumond is an eco-friendly water-based product that can remove 15 layers of paint without any harmful chemicals. There are no noxious fumes or toxic spillage and Dumond’s strip is in fact biodegradable.

Dumond’s marine paint remover works well on wooden boats, fiberglass and metal. On fiberglass boats Smart Strip will remove the antifouling paint without harming the gelcoat underneath.

Because Smart Strip doesn’t have harsh chemicals it should be left on longer than even the instructions suggest. It won’t hurt. Can even be left on overnight. Professionals won’t use this product because it takes too long, but amateurs can afford to let their handiwork do its thing.

Another solution that doesn’t punish nature is the Sunnyside Multi-Strip Advanced Paint & Varnish Remover. It too contains no methylene chloride, effectively clinging to vertical paint surfaces and pulling up to 15 layers away from all boating substrate materials with little spillage.

After applying Multi-Strip with either brush, spray or roller, wipe away from surfaces that are not intended for paint removal with a cloth. Wait 3-5 hours depending on the temperature and scrape away.

Sticking to the less-toxic category of chemical paint strippers, Citristrip Stripping Gel is applied with a roller and a cellophane wrap is spread over the target area to keep the gel from drying out. The longer it stays on, the more layers are removed (up to 24 hours).

Check out the video demonstration below. If you’ve avoided chemical paint removers before and think badly about them after seeing how much easier stripping can be you have the stubbornness of a sailor.

Watch this video for a demonstration of Citristrip:

Citristrip works on wood, fiberglass, and metal boats, though NOT on aluminum vessels.

Sandblasting the Old Paint off Your Boat

Sandblasting, or abrasive blasting is an effective way to get rid of bottom paint on steel and aluminum boats. You’ll need an enclosed environment with protective equipment for both your face and ears.

Soda blasting is relatively new on the scene and is safe for use on fiberglass boats. Sandblasters leave pits…

Compressors shoot streams of sand, dry ice, ground corn cobs, steel beads or recycled glass out of hand-held nozzles that look like rifles. By adjusting the pressure of the gun, you can calibrate how many layers get removed and there’s instant gratification.

Check out some satisfying sandblasting on a boat in action:

Professionals at a dry-dock facility will likely use sandblasting, but it’s more expensive and can be time-consuming for private boat-owners. Ideally, two or more boat owners rent a machine together–one with a more powerful compressor–helping each other out both economically and practically.

It’s better to have a higher cubic foot per minute (CFM) ratio to make the job go quicker, which costs more. Hence, getting a bunch of boat-owning cadres to go in on it together.

You’re going to need a unit with 100 psi and ideally 250 CFM, though 175 CFM will do. Rather than buy a unit at Homedepot that won’t work for you, talk to the weathered boat gurus at the harbor. Ask around and get references.

To read more in-depth about a boat-building project with more experience sandblasting than me, check out the Mimi-Jane page for a sandblasting-101.

Fiberglass Bottom Boat Paint

A boat made of fiberglass is light, yet very strong. Pound for pound, fiberglass is stronger than steel. In fact, a fiberglass boat is so durable, it easily outlasts any marine paint, which means most fiberglass boat repair involves boat paint. Note that some boats might have gelcoat resin instead of paint.

Some fiberglass boats with a healthy gel resin cover might not need painting. You can see it because it’s smooth and lovely. If you’re buying a boat and the previous owner polished the vessel to look more presentable, make sure wax was applied too.

If you’re purchasing a boat that’s been harbored in warm waters for a longer period of time, there’s also a chance of some blistering. That’s what happens when water has penetrated the fiberglass and creates a pustule that can swell to a bigger bulge or blister.

In most cases, the gelcoat will be intact and another protective layer is all that’s needed to maintain the health of a boat’s underside.

You often get what you pay for, but even with many lower-priced boat paints, it’s hard to mess up painting a fiberglass vessel. Don’t be intimidated by the job. Just do it.

See history of the fiberglass boat.

Gelcoating is much more time-consuming and complicated than paint, it should be done by a pro if it’s a big job. If it’s only a touch-up or small repair job, TotalBoat’s polyester Gelcoat product is a versatile and accessible solution.

Marine bottom paint for fiberglass is not the same as gelcoat and it can be applied over existing gelcoat layers.

But!!! Painting over a gelcoat will present some challenges that need to be addressed. You’ll have to thoroughly sand the surface down to the gelcoat to make sure no blistering or resin damage exists. Then it’s a good idea to apply a primer to ensure a good stick between paint and surface.

Fiberglass Repair Kits are also pretty straight forward and describe in detail how to fix dents and blistering with little fuss or muss. Just follow the instructions. You can sand the repaired area afterward and apply paint.

West System Epoxy sets are brilliant and work both for fiberglass and wooden boats. Take time to follow instructions, make sure temperatures are ideal, and it usually works out just fine. Read their more in-depth manual for fiberglass repairs with West System Epoxy.

Preparing a fiberglass boat to be painted

All residual wax needs to be removed using a specific solvent de-waxer. Sand the surface using 180-220 grade grit sandpaper. Brush all dust and particles away and rinse. When dry and free of particles, use a primer following the instructions on the container.

Pettit Bio-Blue Surface Prep can get your fiberglass boat ready for a full bottom paint job.

For warmer climates like Florida, TotalBoat has a strong product that doesn’t cost as much as alternatives, doesn’t stink as much and works on all surfaces. The TotalBoat Dewaxer & Surface Prep will do the job.

Check out a video of this solution being put to use:

If bubbles are noticeable on the hull of a fiberglass boat, chances are there is water trapped underneath the surface. These are called resin blisters and, left unchecked, will grow. They aren’t terribly hard to deal with, but they take time.

Look at how one boater repairs resin blisters on his fiberglass boat:

Dos & Don’ts of Bottom Boat Painting

Dos:

• Get the right equipment – if using water-based paints, for example, synthetic rollers and brushes are better.
• Make sure all paints are compatible. Some antifouling paints don’t dance well with some primers.
• Always follow instructions on marine paint cans and canisters.
• Spread the paint on very thin. Go as thin as you possibly can.
• Wrap your rollers and brushes in bags and remove air so they stay moist for further use.
• Choose the right day to paint. Rainy days don’t work!
• Clean up immediately. It’s always easier to scrape off zebra mussels immediately after a boat has been hauled up. Equally, paint is easier to clean off shoes and equipment before it has dried.
• Dispose of your canisters and cans in the right way. Usually each harbor will have a hazardous materials dumping spot.
• Soft paints (ie. ablatives) can be applied over hard paints (ie. epoxy-based).

Don’ts:

• Buying a cheaper brush will not look good.
• Applying extra coats on top paint that’s not dry will compromise protection
• Never use soaps to rinse hull before applying a coat of marine paint as some residual salts will negatively affect adhesion
• Sometimes a light sanding or cleaning for removal of old paints and resin is all that’s needed, other times it needs to be stripped off.
• If using a pressure washer to remove old paint, don’t blast the boat close to the water because some of the paint will end up unnecessarily in the ecosystem.
• When using a pressure washer, don’t turn up the pressure over 1800 psi unless several layers of paint need to be removed, and don’t use it on wood unless the setting is turned down.
• Don’t apply hard paints (ie. epoxy-based) over softer layers (ie. ablatives)

If you already have a question about marine boat paint or a comment about maintaining your boat, leave a remark in the comment section below and share your experience with it.