Cathelco have supplied marine pipework anti-fouling systems for a complete class of fleet replenishment oilers serving the United States Navy. The 14 Henry J. Kaiser Class vessels are operated by the Military Sealift Command and provide underway replenishment of fuel for U.S. Navy ships at sea and jet fuel for aircraft assigned to aircraft carriers. The final vessel in the series to be installed with a Cathelco system will be the USNS Patuxent a fleet replenishment oiler which was built at the Avondale Shipyard and launched in 1991. The orders for systems were won by Allied Marine Services Inc., Cathelco’s long establish agent serving the military sector and a geographical commercial sector in the USA.
The Cathelco system is based on the electrolytic principle and designed to protect seawater pipework systems against blockages caused by barnacles and mussels which can restrict the flow of cooling water to engines and auxiliary systems. On the USNS Patuxent, the system protects four seachests with flow rates of 2,000m3/hr. Each of the seachests is fitted with two copper anodes and one ferrous anode which are wired to a control panel.
In operation, the copper anode produces ions which are carried throughout the pipework system and create an environment where mussel larvae do not settle or grow. At the same time, the ferrous anode releases ions into the system which coat the internal surfaces of pipes to suppress corrosion. Ferrous anodes are used to protect cupro-nickel pipework, as is the case on the USNS Paxuent, whereas aluminium anodes are more commonly used on vessels with steel pipework.
In the UK, Cathelco are supplying marine pipework anti-fouling and hull corrosion protection equipment for HMS Queen Elizabeth and HMS Prince of Wales, two aircraft carriers which are being built for the Royal Navy.
During 2009 equipment was also supplied for eight frigates in the FREMM European multi-mission programme which are being built by the DCNS yard in L’Orient. Another order came from Spain where Cathelco are supplying systems for four frigates which are being built for the Buques de Accion Maritima (BAM) project.