Cathelco has secured a contract to install a seawater pipework anti-fouling electrolysis tank system on the MT Onozo, an Aframax tanker.

The vessel is currently being converted to an FPSO at the MHB yard in Pasir Gudang, Johor, Malaysia.

Following the conversion, the vessel will be renamed FPSO Cendor and will be operated by Petrofac Malaysia in the Cendor offshore oil field in West Malaysia.

Cathelco’s subsidiary Cathelco South East Asia will build the electrolysis tank to American Society of Mechanical Engineers (ASME) standards.

Cathelco’s tank, which will house two copper anodes and one ferrous anode that are fed with an electrical current from a control panel, will help protect seawater inlets and pipework against blockages caused by barnacles and mussels.

The electrolysis tank will protect the vessel’s pipework, which is made from cupro-nickel, and contains a dedicated cathode to offer a return path for the current and reduce the risk of stray current corrosion.

Cathelco spokesperson Julianna Measures said the electrolysis tanks provide a practical solution to the needs of FPSOs requiring protection for several inlets from bio-fouling.

"One of the advantages is that the anodes can be easily replaced without drydocking, an important factor on vessels which remain on station for many years," Measures said.

The tank doses seawater with copper ions to create an environment that ensures fouling species larvae do not settle or breed over the inlets.

The dosed water will be distributed to intakes including fire-fighting pumps and ballast water pumps, as well as machinery room and pump room seachests.

The tank system will also suppress corrosion with the help of ions from the ferrous anode, which create a protective oxide layer on the internal surfaces of pipes.