9 Common Questions Associated With Bottom Painting A Boat With Antifouling Paint

The frequency of bottom paint application is one of the most common questions that boat owners ask. The irony of boating, be it for commercial or recreational purposes, is that the main necessity for the activity – water- is also potentially the main source of problems. The destructive effects of marine growth make it necessary to bottom paint your boat, which is going to be the center point of this post.

How Often Should I Bottom Paint My Boat?

So, how often should you bottom paint your boat? Well, this depends on the type of bottom paint that you apply, how often your boat is in use throughout a year, and where or how you store your boat. Generally, you should apply bottom paint once a year. However, some bottom paints can effectively last for two years.

If your boat lives afloat or you use it frequently, you should have it checked every year to determine whether it needs bottom paint application. Most of the time, it probably does. In some cases, you may need to bottom paint your boat after each season. This mostly applies to the boat used for commercial purposes. If your boat lives ashore and has been washed down, it may only need bottom painting every other year.

What Is Antifouling Marine Paint (Bottom Paint)?

If you are new to boating, you may be wondering what antifouling marine paint, also referred to as bottom paint, is. It is a special type of coating that is applied as the outboard layer to the hull of a boat or ship in order to impede the growth of fouling aquatic organisms.

Fouling organisms can significantly affect the performance and durability of your boat. If left to flourish on your hull, they also drive up your boat’s fuel consumption. Antifouling marine paint contains biocides that repel these organisms when released at a certain rate into the water surrounding the hull.

Bottom paints are usually applied as part of multi-layer coating systems that have other functions other than the antifouling properties. There are three main categories of antifouling marine paints. They include hard paints, ablative (soft) paints and hybrid paints.

Hard paints are also referred to as contact leaching paints. This type of bottom paint dries to form a porous film, which is packed with biocides that leach out when they make contact with water. This process is designed to release biocide throughout a season.

However, hard bottom paints do not retain their antifouling properties when kept out of water. As such, they are not suitable for trailer boats. Their main advantage is resistance to rubbing and abrasion, making them ideal for racing sailboats and powerboats.

Ablative paint types are more efficient at releasing biocides and utilize less biocide to offer more antifouling protection. These paints are widely applied on recreational boats.

Hybrid paints, also known as semi-hard paints, are antifouling paints, which incorporate the advantages of the hard and ablative paints into a single product. They provide a smooth surface that resists buildup while being able to hold up to repeated haul-outs and faster speeds without losing protection.

Does Bottom Paint Slow Down A Boat?

bottom antifouling paint going on a boat

The short answer is that yes it can. There is some debate about this effect on boating forums. If the hull of your boat has a nice and smooth bottom paint job, then the loss of speed will not be noticeable.

However, if you have been adding multiple coats of antifouling marine paint each year, and your boat has not had much use, the layers will compile. You will end up with significant drag, and the boat will slow down.

In addition, ablative antifouling paint is designed to shed its protective abilities over time. The paint job may get a little rough or slime may begin to grow. If this is the case, then you will experience speed loss. The bottom line here is that proper maintenance practices will ensure that the speed loss is unnoticeable.

How Much Does It Cost To Bottom Paint My Boat?

So, how much does it cost to bottom paint a boat with antifouling paint? Expect a professional bottom paint job to cost between $15 to $100 per linear foot with the average cost being in the $15 to $20 per linear foot range.

Here’s the rest of the story:

The cost of bottom painting your boat depends on whether you opt to hire a professional or do it yourself. Doing a DIY painting project will save you some money, but it will cost you time and probably paint job quality. Since boats come in different sizes, I have used cost per linear foot to determine the cost of bottom painting a boat.

For a professional paint job, the cost ranges anywhere from $15 to $100 per linear foot with the average cost being $15 to $20 per linear foot. You will be subject to the higher end of the price range if your boat requires a lot of work before the bottom paint can be applied. Also, the location of your boat is a determining factor. The prices will be higher if your boat has to be hauled or blocked before bottom painting.

If you go the DIY route, the cost will depend on the size of your boat and the type of bottom paint you use. Depending on the brand, a gallon of antifouling paint can cost anywhere between $15 and $200. Aside from the paint, you will need supplies, including paint brushes, rollers, sandpaper, paint trays, masking tape, goggles, gloves, a respirator and drop cloths. Taking these into account, a DIY project can set you back anywhere from $50 to $500.

What Are The Available Brands of Bottom Paint?

9 Common Questions Associated With Bottom Painting A Boat With Antifouling Paint 19 Common Questions Associated With Bottom Painting A Boat With Antifouling Paint 2

The most notable brands of antifouling marine paint include:

  • Petit Paint
  • West Marine
  • Interlux
  • Sea Hawk
  • Z-Spar
  • Forespar
  • Harken
  • Mdr
  • Ocean Accessories
  • Prop Armor
  • Prop One

Shopping Tip: Whether you plan to do the bottom paint yourself or hire a professional, to make things easier, I created these quick links to help locate most of these bottom paint brands on West Marine or the bottom paint options on Amazon. These are affiliate links and if you shop using these links, I get a referral fee. I appreciate your using these links to make a purchase.

Do You Have To Bottom Paint A Boat?

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In some case, it is not necessary to bottom paint a boat. Not all boats have bottom paint. If you leave your boat on the water for short periods, then you do not need to bottom paint it.

This is also the case if you store it on a lift, trailer, or in a dry storage facility. It is much more feasible to conduct maintenance on your hull through regular cleaning and a high-quality coat of wax. Boat owners generally have one issue with bottom painting their boats. Once you apply antifouling paint, you have to maintain it with regular cleaning, scrapping off and repainting.

However, there are other cases where the bottom painting is a must. If your boat stays on the water year-round or for most of the boating season, you will defiantly need bottom paint.

Is Boat Bottom Paint Toxic?

Yes, antifouling marine paints are toxic and can be harmful to your health and that of the marine environment if not handled correctly. This is the reason why there are safety procedures when handling bottom paint. Direct contact with some antifouling paints can cause skin and eye irritation and inflammation.

To keep yourself safe, always ensure that you always wear the appropriate safety gear to avoid breathing in the vapors or getting the paint on your skin. These include goggles, chemical-proof gloves, respiratory protective equipment, full-body overalls, and covered shoes.

In addition, it is advisable to set up a controlled work area when applying bottom paint. This serves to prevent the bottom paint from coming into contact with bystanders (overspray) or entering the environment.

Always read the product labels on bottom paints carefully. The label contains information regarding the potential hazards of the paint and what it contains. It also informs you of the precautions to handle the product and how to safely dispose of it.

It is worth noting that there are certain types of antifouling solutions that are non-toxic and environmentally friendly. Several companies are offering alternatives to conventional antifouling paints such as innovative covers, ultrasonic systems, and silicone-coated adhesives.

How Long Does It Take For Bottom Paint to Dry?

The time it takes antifouling marine paint to dry depends on several factors. These factors include the type of bottom paint, the hull temperature, and relative humidity. Hard bottom paints take longer to dry than the ablative bottom paints.

It will also take more time for bottom paint to dry when the hull temperatures are cooler, and the relative humidity is high. Generally, you can recoat antifouling marine paint after about 4 hours, and you can launch your boat about 16 hours after you have it bottom painted. It takes about 72 hours to achieve a full bottom paint cure.

Do Aluminum Boats Need Bottom Paint?

do you need to bottom paint an aluminum boat

Yes, they do. Aluminum boats are also susceptible to marine fouling, although it is to a lesser degree than plastic boats. However, different antifouling marine paints are recommended for different types of boats.

The bottom paint you use on an aluminum boat should be the one designed specifically for aluminum hulls. Many antifouling paints contain copper oxide. If you have an aluminum hull, you should avoid these bottom paints.

Paint containing copper will eventually eat away at the aluminum similarly to how salt would corrode an unprotected metal hull. If you have an aluminum boat, go for paints with a metal-free biocide such as Econea.

Closing Thoughts:

Overall, bottom painting your boat is a very important component of its maintenance schedule. Not only does it help increase the lifespan of your hull, but also improves the boat’s fuel economy, maneuverability and decreases the chances of your hull logging water. While this piece focuses on antifouling, note that there are many other aspects of proper board maintenance.

Watch The Bottom Paint Video!