Boat Bottom Paint: Getting the Most Protection

To new boaters, the idea of paint on the waterside part of your hull can be a little confusing and intimidating. Most people see paint in terms of house paint or auto paint. It’s not typically seen as a water-resistant finish. This is why marine paint is so different than other kinds of paint. Marine paint is not the same as the paint you buy at Home Depot. Marine paint has special additives which give it better temperature resistance, better adhesion and longer life.

When someone says “boat bottom” they are talking about the waterside portion of your hull that’s constantly under attack from varying water temperatures, marine life and sun. As such, you need a very strong paint to resist these constant attacks that can degrade and even destroy your hull. The kind of bottom paint you use on your boat depends on what kind of boat you have.

Fiberglass hulls are the most popular kind of boats. They are prefabricated at a factory and often come with a gelcoat base that can protect the hull for a long time. Many gelcoats require annual maintenance though, and this can be an ugly part of owning a gelcoat fiberglass boat. Many boaters choose to strip their gelcoat and replace it with paint.

Wood hulls need to be very well-made before you apply any paint. This means you need to ensure you have proper chinning or has been sealed so the paint doesn’t flex as the wood expands with temperature change. This can cause the paint to crack, which can be disastrous to your hull. You can use one-step or two-step epoxy, or a varnish on your bottomside wood hull.

Boat Bottom Paint

Boat Bottom Paint

If you have a metal boat, preparation is the biggest challenge you face when painting it. You must ensure your metal is properly sanded, sealed, and treated before you paint it. You also should ensure you treat it with an anti-oxidative primer so you prevent rust and corrosion, which can destroy a metal hull. Since metal is very popular for new boaters, it may be worth having a professional prep your surface for you before you paint.

You need to remember that you can’t use just any paint on the bottomside of your boat. Bottomside paint often has special antifouling properties that keeps marine life from attacking your hull. Bottomside paint can come as an epoxy as well, which can be applied as a one-step or two-step process. One step paint provides a good amount of protection, but if you want maximum protection, a two-step epoxy is the way to go. Two-step epoxy requires mixing and often the addition of thinning agents for good adhesion and brushing.

When applying bottomside paint, you should use the right kind of primer under the actual layers of paint. This protects your hull. You should also sand in between coats as instructed by the label because this improves adhesion and helps your surface be very smooth and uniform. Properly applying your paint is the essential step you must take to ensure a professional protective job.

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