Shipyards from Turkey have contracted Cathelco for ICCP hull corrosion protection and systems to protect pipework from seawater fouling. A new 128.5 meter long subsea IMR and construction vessel, based on the ST-259 design, being built for Volstad Shipping (Norway) at the Tersan Shipyard with a 25 meter beam is one of the orders and is due for delivery in late 2015. The vessel will be powered entirely by Cathelco systems.
Impressed Cathodic Protection (ICCP) is the technology that will be used by Cathelco to protect the hull of the vessel from corrosion due to seawater. As part of this process, a number of anode discs are connected to the hull and electricity is passed through them via a central control panel. The current that flows through the anodes causes an electrochemical reaction to occur, neutralizing all possibility of corrosion. The flow of electricity through the anodes is monitored by means of a set of reference electrodes, which automatically detects the electrical potential difference at the hull-seawater interface. Based on the feedback, signals are sent to the control panel to control the voltage supply to the anode discs attached to the hull.
Additionally, a mechanism to prevent internal pipework that carries engine coolants from getting damaged by seawater or blocked by sea creatures such as mussels and barnacles is being installed on the vessel by Cathelco as well.
Similar fit-outs have been ordered by Tersan Shipyard for another multi-purpose platform supply vessel as well; this vessel has been commissioned by Tidewater Marine. Designed to operate in Arctic waters, Tidewater Marine’s subsidiary, the Norwegian Troms Offshore Supply Group will be using this ship.
Anne Siodlak, who is working on these vessels says, “Water in the Arctic region is significantly different from seawater in warmer parts of the world, as it contains more fresh water. This means that there is higher resistivity at the hull-water interface and can be overcome only by using a higher voltage during the ICCP process. Volstand and Tidewater’s vessels belong to the DNV DEICE class and therefore require 50 volts to be applied to the hull during the anti-corrosion treatment process”.
Yet another order which involves the treatment of a live fish carrier vessel being constructed for Internship AS, Norway, has similar requirements. The vessel is nearly 70 meters long, and is capable of carrying several live species of fish cultured in farms. This vessel also needs Cathelco’s ICCP hull corrosion protection system, in addition to pipework protection.
Pipework protection, which serves to prevent engine coolant pipes from getting blocked, requires the use of copper and aluminium anodes. Installed in strainers or sea-chests, the anodes are connected to the piping and a central control unit. When a current is passed through the wiring, the copper anode releases ions that coat the inner linings of pipes, and create an environment that is unsuitable for mussels or barnacles to grip and settle. A luminium anodes (or iron anodes, which will be used in the case of the live fish carrier vessel which has pipework made of a copper-nickel alloy) simultaneously create ions which coat the piping and prevent the metal from coming into contact with seawater, thereby, saving it from corrosion.
Four passenger ferries being built for Izmir Metropolitan Municipality are also scheduled to undergo Cathelco’s protection treatment for pipework; this is an order commissioned by the Ozata Shipyard. The ferries are 39 meters long and can carry over 400 passengers at about 40 knots. Cathelco will be responsible for the installation of omni-anodes, two engine cooling systems and a winch mechanism.
Erdal Dicncer, who is the managing director at Industrial & Marine Supplies which is Cathelco’s agent in Istanbul has said, “These small and versatile anodes are ideal for use on passenger ferries where flow rates are relatively small, but vital in maintaining engine efficiency. Cathelco’s anti-fouling systems have been widely used on Turkish ferries and have proved their effectiveness beyond doubt”.