Published: Dec 05 2018
A hull free of marine growth keeps a boat working at its peak hydrodynamic performance level. A clean hull is safe, fast, and efficient; a bottom that is fouled (the appropriate maritime industry term) cuts speed and maneuverability and lowers fuel economy. Also, a clean hull makes a boat far more marketable to potential renters and looks good when underway.
If your boat stays in the water for at least part of the year, a good coat of anti-fouling paint will enable peak performance. Many boaters find bottom painting messy, tedious, and time-consuming, but it is one of the key preventative maintenance jobs that keeps a boat shipshape.
It is important to remember that modern bottom paints are designed to perform a specific purpose, use highly-developed science to do their jobs, come in a dizzying array of names, removal and application techniques, and have complex paint and hull compatibility issues. Stringent air, soil, and water pollution protection measures are involved in hull cleaning and painting. These and other factors, including regional environmental regulations, can be overwhelming for a boater tackling a hull paint job for the first time. The best approach may be to find a boatyard that provides hull-painting services to do the job initially and to participate as much as possible in the project to learn how to do it correctly.
Protecting hulls from marine growth has its roots in the days of sail, when wooden sailing vessels were severely affected by barnacles, algae, other creatures, and seaweed that attached to their hulls. Thin sheets of copper were affixed to the hull to prevent the marine growth, which was generally effective. As steel became the predominant material for ship hulls, paints that contained copper and later, tin, were developed to protect the hulls.
Beginning in the 1950s, anti-fouling paints were formulated with other special chemicals like tributyltin (TBT), organotin compounds, and other biocides to impede marine organism growth. In the 1960s and 1970s, bottom paints containing TBT became the industry standard for anti-fouling applications on commercial and recreational vessels. The substance was banned a few years ago around the globe because of its serious toxic effects on humans, marine life, and the environment.
The following tips about bottom painting provide a very basic primer about bottom painting, information about paint types, and recommendations about how to approach a painting project.
The combination of advanced research in paint technology and marine biology continues to produce innovative bottom paints that are increasingly less toxic to the marine environment and to humans. One type provides good anti-fouling protection by producing hydrogen peroxide when exposed to the sun or artificial light. Another development for replacing cooper and tin in anti-fouling paint is slime. Micromesh covering a boat’s hull contains a material which turns into a viscous slime on contact with water and coats the micromesh. The slime constantly ablates, carrying away microorganisms and barnacle larvae as it wears away.
Today’s bottom paints are designed to perform a specific purpose, use highly-developed science to do their jobs, and have complex paint and hull compatibility issues. Strict environmental measures around the country affect how boat hulls are cleaned, stripped, and repainted. Understanding all facets of hull painting and the variety of available paints can save money, time, and effort, and provide protection for the hull that meets user needs.
Learn about the various types of hulls and what they are best used for in this article.