As of August 1, 2022, we have agreed with Cathelco to become the exclusive point of contact in North America (US + Canada) for Evac’s Cathelco marine growth prevention parts and services. This partnership will enhance turnkey service, significantly improving our product and service offerings for our valued North American customers. With a shared history and aligned values that began 68 years ago in Canada, EMCS Industries and Cathelco Ltd are motivated to provide a focused provider in North America, offering unparalleled expertise in antifouling and anticorrosion solutions.
marine growth prevention system
Cathelco’s marine growth prevention system (MGPS) utilizes pairs of copper and aluminum anodes mounted in sea chests or strainers connected to a control panel. These anodes release copper ions into the seawater flow, creating an environment that prevents the settlement and multiplication of barnacles and mussels. Introducing copper ions in small concentrations disrupts marine larvae’s settlement sequence, preventing them from adhering to surfaces and passing harmlessly through the cooling water system.
The Cathelco MGPS system also addresses corrosion concerns by creating a cupro-aluminum film on internal pipe surfaces, suppressing corrosion and protecting against biofouling. This dual-action system ensures efficient fouling control and reduces corrosion rates in the seawater pipework, extending the lifetime of equipment connected to the system.
A dual-action system
The action of the copper ions is assisted by aluminum hydroxide that is created by the aluminum anodes flocculating the released copper from the copper anodes. This highly gelatinous copper-aluminum hydroxide floc is carried throughout the system and spreads into the slow-moving areas near the pipe surfaces, where marine larvae are most likely to settle. As a result, the larvae instead pass directly to discharge.
At the same time, a cupro-aluminum film builds up on the internal surfaces of the pipes to suppress corrosion. This way, the system has a dual action, protecting seawater pipework against biofouling and corrosion.
Corrosion is accelerated in two ways. The biofouling on a metal surface leads to a decreased oxygen concentration below the fouling layer. This area becomes anodic when exposed to oxygenated seawater, resulting in pitting corrosion under the fouling. Another cause of corrosion is bacteria – sulfate-reducing and iron bacteria are well-known examples of microorganisms whose biological activity or metabolic by-products can cause corrosion. These bacteria live in areas with a low oxygen concentration, for instance, under a layer of aerobic fouling organisms or in de-aerated water such as that found in oil storage tanks and well flood water—efficient fouling control results in a reduction in pitting and crevice corrosion.
Most Cathelco marine growth prevention systems have a dual action, eliminating biofouling and suppressing corrosion. Where steel pipework is used, the corrosion suppression anodes are made of aluminum, whereas cupro-nickel pipework is protected using ferrous anodes. When these anodes are fitted, corrosion rates are significantly reduced, resulting in a longer lifetime for the pipework and other equipment connected to the seawater system.
Sea chest or strainer-mounted anodes
Anodes are typically fitted in sea chests during vessel construction or retrofitted in seawater strainers when necessary. In cases where the Cathelco system replaces existing chemical-based antifouling equipment, the anodes can be mounted in electrolysis tanks to utilize existing pipework, reducing installation costs.
Trust in the comprehensive capabilities of Cathelco marine growth prevention systems for effective biofouling control and corrosion suppression, ensuring optimal performance and longevity of your marine systems.
Options and features of the Cathelco MGPS
- Steel pipework protected by copper and aluminum anodes
- Cupro-nickel pipework protected by copper and ferrous anodes
- Sea chest-mounted anodes are typically installed during vessel construction and replaced at drydocking
- Strainer-mounted anodes can be replaced when the vessel is in port
- Electrolysis tanks can be used to replace chemical systems or in specialized applications where sea chest or strainer mounting is not possible
- Environmentally friendly, chemical-free systems typically operate with copper concentrations of just two parts per billion.