For vessel operators, corrosion protection rightly receives significant attention. Impressed current cathodic protection (ICCP) systems are well understood across the marine industry, and their role in safeguarding hulls and submerged structures is widely recognised. Marine growth prevention, however, is a less prominently discussed technology; yet the consequences of biofouling in seawater systems can be just as damaging to vessel reliability and operating costs.
This article explains what marine biofouling is, where it poses the greatest risk on a vessel, and how Corrpro Europe’s Anfomatic® Marine Growth Prevention System addresses it through a controlled, chemical-free electrolytic process.
What Is Marine Biofouling and How Does It Develop?
Marine biofouling refers to the accumulation of biological organisms on surfaces exposed to seawater. The process begins within hours of a surface coming into contact with seawater, as dissolved organic molecules form a conditioning film. Bacteria attach to this film within the first day, creating a biofilm that serves as a substrate for larger organisms.
Within days to weeks, macro-fouling organisms, including barnacles, mussels, tubeworms, and algae, begin to colonise the surface. In seawater pipework and internal systems, where flow conditions and temperature ranges create favourable conditions for settlement, this process can progress rapidly and go undetected until blockages or reduced flow rates indicate a problem.
Unlike hull fouling, which affects external hydrodynamic performance, biofouling in internal seawater systems is hidden from view and not addressed by antifouling hull coatings. It requires a separate, dedicated prevention approach.
The Areas of a Vessel Most Vulnerable to Biofouling
Marine growth in internal systems concentrates in areas of consistent seawater flow and elevated temperature; the conditions that favour larval settlement and rapid growth. The most vulnerable locations on a typical vessel include:
Sea chests and sea inlets: The primary point of entry for seawater, sea chests are directly exposed to ambient seawater and its full biological load. Barnacles and mussels establish colonies here readily, and the accumulation can progressively restrict flow.
Strainers and filters: Biofouling in strainers accelerates blockage and increases the frequency of cleaning requirements, adding to maintenance workload and creating potential for unplanned downtime.
Seawater pipework: Internal pipework carrying cooling water is particularly susceptible. Reduced bore caused by marine growth insulates pipe walls, restricts flow rates, and can accelerate under-deposit corrosion.
Box coolers: Heat exchanger performance is highly sensitive to fouling. Even a thin layer of biological growth on cooler surfaces acts as a thermal insulator, reducing cooling efficiency and increasing the thermal load on propulsion and auxiliary systems.
Firewater systems: Seawater firewater systems that are infrequently operated are especially prone to heavy fouling in standby conditions, where the absence of regular flow allows organisms to establish undisturbed.
The Operational and Financial Consequences of Unmanaged Biofouling
Left unmanaged, marine growth in seawater systems causes a range of operational problems that compound over time. Reduced cooling efficiency leads to elevated engine and auxiliary temperatures, increasing mechanical wear and the risk of unplanned shutdowns. Flow restrictions in firewater systems raise compliance concerns and can affect system reliability in an emergency.
The maintenance burden is significant. Manual cleaning of sea chests, strainers, and coolers is time-consuming, often requires confined space entry, and typically occurs during dry dock; by which point the accumulated fouling may have already caused corrosion damage beneath the biological layer. Unplanned maintenance between dry dock periods adds further cost and scheduling disruption.
Biofouling also contributes to accelerated corrosion in ferrous pipework. Biological deposits create differential oxygen concentration cells on metal surfaces, driving localised pitting corrosion that can undermine pipe integrity independent of the vessel’s cathodic protection system.
How the Anfomatic® MGPS System Works
The Anfomatic® system operates on the principle of controlled electrolytic cupric ion release. Copper and aluminium anodes are mounted in the vessel’s sea chest or strainer, connected to a dedicated power unit. When energised, the copper anode releases copper ions into the flowing seawater at very low concentrations, typically measured in parts per billion.
At these concentrations, copper ions create an environment in which barnacle and mussel larvae will not settle or develop. The effect is preventive rather than reactive: the system maintains conditions that inhibit the initial stages of biofouling colonisation, avoiding the need to address established growth.
The aluminium anode performs a complementary function. Dissolved aluminium forms a hydroxide compound that is carried through the seawater system with the water flow. This compound modifies the surface films that form on internal ferrous pipework into a more stable and protective form, reducing the rate of corrosion within the system. Where non-ferrous materials are used in the pipework, soft iron anodes are specified in place of aluminium.
The system is automatic in operation. Output from the power unit can be adjusted to reflect changing conditions — water temperature, salinity, and tidal state all influence the rate of ion release required — and can be interlocked with the main pump controller so that the output is maintained at an appropriate level even when pumps are not running.
The Anfomatic® system requires no chemicals, no manual intervention during normal operation, and no significant modification to existing seawater systems. Anode lifetimes are pre-calculated to coincide with scheduled dry dock intervals, minimising maintenance requirements and aligning replacement with planned maintenance windows.
MGPS Within a Broader Vessel Corrosion Protection Programme
MGPS and ICCP address different aspects of vessel protection and are complementary rather than interchangeable. Corrpro Europe’s Aquamatic® ICCP system protects the vessel hull and other external submerged metallic structures from corrosion through cathodic polarisation. The Anfomatic® system addresses biofouling and corrosion within internal seawater pipework and systems, where ICCP has no reach.
Together, they provide comprehensive protection against the two primary degradation mechanisms — electrochemical corrosion and biological fouling — that affect a vessel’s structural and operational integrity over its service life. Corrpro Europe designs and supplies both systems, and the two can be specified and integrated as part of a coordinated vessel protection package from a single, experienced supplier.
Spare Parts and Lifecycle Support from Corrpro Europe
Corrpro Europe maintains extensive stocks of genuine Anfomatic® spare parts and replacement anodes, supporting current systems and legacy equipment previously supplied under the Wilson Walton brand. This is particularly relevant for vessel operators managing older installed systems, where sourcing genuine replacement parts from the original equipment manufacturer provides confidence in material quality and system compatibility.
Corrpro Europe can also provide spare parts for systems manufactured by other suppliers, supporting a wide range of competitor equipment across the market.
Lifecycle support extends beyond parts supply. Corrpro Europe’s technical team provides remote troubleshooting and log sheet review, with site visits available when on-site assessment or component replacement is required. This support is available across ports globally, providing responsive assistance regardless of where a vessel is operating.
For full technical details of the Anfomatic® system, including anode specifications and system configurations, download the Marine Cathodic Protection and MGPS datasheet.
Speak to Corrpro Europe
Corrpro Europe has supplied MGPS and ICCP systems to commercial vessels, tankers, cruise ships, naval ships, FPSOs, and offshore platforms worldwide. As the original equipment manufacturer of the Anfomatic® system, we provide design, manufacture, supply, and ongoing lifecycle support from our facility in Stockton-on-Tees.
To discuss MGPS system requirements, spare parts supply, or a combined vessel protection solution, contact the Corrpro Europe team.
