Common marine coating problems and their solutions
Marine vessels and structures face high stress and harsh environments. Protecting them against the problems they face in the normal course of business is just as important as their core functions.
Assaults on these critical assets come from all directions: The waters they travel, the cargo and equipment they carry and even the sun. Solving these problems relies, in part, on a comprehensive marine coatings program. That starts by better understanding the problems.
Corrosion
The most obvious and familiar problem marine vessels and structures face is corrosion—a loss of mass caused by a metal’s natural reaction to the atmosphere around it. It can occur in any area of a vessel or marine structure.
Salt water is the most notorious catalyst for corrosion because it supports the electrochemical environment in which corrosion thrives. Ship hulls are especially susceptible because they’re submerged in water almost all the time. But other exterior and interior structures are prone to corrosion, too, because it occurs anywhere metal and moisture are in contact.
Abrasion
Another problem encountered on marine vessels and structures is abrasion, the repeated forceful impact of materials against a surface.
The most common form of abrasion on marine assets is seawater that continuously batters a ship’s hull. But it comes in other forms, too, such as stiff winds and rain whipping against an exterior structure or from onboard equipment or cargo like fertilizer, coal, or stone.
Abrasion can damage structures and hamper asset performance over time. But some abrasion is significant enough to damage protective coatings or linings. That damage sets the stage for corrosion or chemical attack that the coating or lining would ordinarily have prevented.
UV exposure
Even with sunny skies and smooth seas, marine assets are at risk. Repeated exposure to the sun’s radiation leads to degradation of some protective coatings. Left unnoticed, the coating could break down to the point of exposing the underlying surface, putting it at risk of further damage or corrosion.
Marine coatings solutions
Coatings form protective barriers between marine assets and the environment, making them an integral part of asset protection programs. Different areas of ships are best served by different types of coatings, depending on their service environment:
Urethane and polyurethane coatings offer solid protection against corrosion and UV exposure. They’re also well-suited for coating in confined spaces because they can be customized to low-VOC formulations. Polyurethane finishes provide added corrosion protection, good color, and gloss retention when aesthetics is a concern.
Acrylic coatings work well in marine settings as part of dual-component systems. Used in conjunction with zinc primers that protect against corrosion, acrylics also provide gloss and color retention.
Epoxies and modified epoxies are best utilized in abrasive environments, such as storage bins, high-traffic or high-stress work areas, floors, or hoppers. High-performance, high-build epoxies are formulated to take a beating from equipment and cargo. Edge-retentive properties make them excellent for stripe coats as well. While epoxies are prone to break down under UV exposure, they can offer great wear protection in exposed environments when topped with a finishing coat.
There are trade-offs when choosing coatings in terms of how much time or money is spent on marine coatings. With multiple ways to protect assets, it comes down to finding the balance between costs and protective properties. AMPP publishes books that explore in more detail how to choose the right marine coatings and related marine coatings topics.
Regular inspections play a critical role
International standards mandate a ship’s new coating be inspected within six months after application and then every one to three years after that. While inspections can be costly, it’s wise to order them frequently so that any problems are caught early and can be more easily addressed. Repair costs compound the longer repairs are put off.
AMPP offers many different resources pertaining to the inspection of industrial and marine coatings: