Bottom paint, or some derivation thereof, has probably been around since the very first boats were made by our ancient ancestors. Back then it was undoubtedly some kind of mixture of tar, or pitch. But then, as now, the purpose of coating the bottom of your boat with something, was the same – to keep barnacles and all manner of other sea creatures from making the bottom or your yacht their home!

Over the years, bottom paints have changed and evolved. In more recent years, regulators have gotten involved to be sure any bottom paint used, meets certain standards of environmental safety. Most of the toxic substances that were used in the past, have now been banned, which has made finding effective and long lasting bottom paints a bit more challenging.

Antifouling Agents

Bottom paint is also known as “antifouling” paint. Its purpose is to keep weeds, algae, barnacles, and other nasty little aquatic critters from attaching themselves to the part of your boat’s hull that remains underwater.

These coatings traditionally included some kind of “biocide” in the mix. For decades the biocide of choice was tin. However, it was soon replaced by copper because of the environmental damage tin was causing when it leached into the waterways.

Marine Growth on Bottom of Boat

Tin is now banned for most marine applications. Copper is a very effective biocide, and generally speaking, the more copper a bottom paint contains, the more effective it is.

However, environmental groups have been raising similar concerns over the environmental impacts of copper, which has led to a new generation of “environmentally friendly” bottom paints and coatings that use little or no copper at all.

What Kinds of Boats Need Bottom Painting

Any boat that is left in the water for any appreciable amount of time, needs to have periodic bottom painting. That means it is required for most motor yachts of any appreciable size, as they are usually not found on a trailer in your driveway!

How often bottom painting becomes part of your yacht’s routine maintenance will depend on many factors, particularly, where your boat is docked, and how long she remains in the water.

Types of Bottom Paints

There are many brands and many types of marine bottom paints. However, they fall into three basic types: ablative paints, hard, or hybrid paint.

An ablative paint, sometimes called a “self-polishing” paint, is designed to wear away a little at a time, layer by layer, releasing its biocide each time a layer “ablates” or wears away.  These are good as long as your boat is used often enough for the ablative action to take place. But, ablative paints are not a good idea for very fast moving boats, as you will accelerate the ablative effect, and wear through the layers too quickly.

applying bottom paint

Hard bottom paints, as the name implies, form a hard coating that doesn’t wear away, making them a good choice for faster boats. But, just because they create a hard coating, do not think of them as permanent, as they work only so long as the copper biocide remains, which does wear out eventually.

A hybrid paint is a combination of the two. But, even hybrid paints are not effective for all boats, under all conditions.

Which type of paint is right for your boat is complex. Many variables come into play, from your boat’s speed, to where she is docked. No one paint can possibly work for all boats, in all types of water, under all weather conditions. As you might imagine, a yacht moored in Martha’s Vineyard in the Northeast, would require a very different type of bottom paint, than one docked here in South Florida!

The bottom line on bottom paint is, that you can trust your yacht manager to know the best coating for your particular vessel.



Operating a motor yacht can be costly. You can reduce your expenses, and avoid costly repairs by keeping her well maintained. On Demand yachting from FYM can help. If you would like to learn more, or if you have any questions or comments about this blog post, do not hesitate to contact our Yacht Management specialists, or call us at (855) 318-6328.