June 16, 2015 - Cathelco are providing hull corrosion protection systems for four corvettes which are being supplied to the Egyptian Navy by DCNS, the leading French defence contractors.
The first of the Gowind 2500 corvettes will be built at DCNS Lorient, but the three others will be constructed in Alexandria with training and technical support provided by DCNS as part of a ‘technology transfer’ initiative.
With a length of 102 metres and a displacement of 2,600 tonnes, the Gowind corvettes represent the very latest in technological advances. The multi-mission combat vessels are equipped with air defence, land strike and ship to ship missiles, enabling them to carry out a range of missions from protection of sovereignty to combating terrorism and illegal trafficking.
The Cathelco impressed current cathodic protection (ICCP) systems will safeguard the underwater surfaces of the vessels against corrosion throughout their operational life.
Each vessel will be installed with 100 amp forward and aft ICCP systems. These will consist of an arrangement of reference electrodes and anodes (mounted port and starboard) wired to a thyristor control panel. The reference electrodes measure the electrical potential at the hull/seawater interface and send a signal to the control panel which automatically raises or lowers the output to the anodes. In this way, the hull receives the optimum level of corrosion protection at all times.
In addition, the corvettes will each be fitted with shaft earthing systems. This is important because even on ships installed with ICCP systems, the turning shafts are electrically insulated from the hull by the lubricating oil firm on the bearings. This can result in damage to bearings and cavitation problems at the tips of propellers. The purpose of the shaft earthing system is to provide a ‘safe’ return path for corrosion currents, avoiding the risk of damage.
On each vessel, the ICCP system controllers have the ability to communicate with each other using RS485 data links. This enables all of the functions of the system to be monitored from the aft ICCP control panel using a touch screen monitor.
“The advantage of this feature is that comprehensive data about the performance of the forward and aft ICCP systems is accessible from one location making it more readily available for detailed analysis”, said Stephen Ellis, Cathelco’s project development manager.
This is the latest in a series of projects where Cathelco have worked closely with DCNS to provide technically advanced systems which meet the most rigorous military standards.
These go back to 2006, when Cathelco started the design and supply of ICCP equipment for 10 frigates in the FREMM European multi-mission programme which are being built by the DCNS yard in Lorient. This on-going project is now on the tenth vessel, one of which is in service with the Moroccan Navy and another ordered by the Egyptian Navy.
The FREMM warships were also installed with Cathelco pipework anti-fouling systems to eliminate bio-fouling in seawater cooling lines.