By inspecting and maintaining the cathodic protection on a vessel by means of FN Diving underwater technicians, you can extend the trouble free life of a vessel dramaticaly.
It is proven that by renewing and maintaining anodes and ICCP systems and performing regular inspections on manouvering and propulsion systems, ships will operate longer without mayor unforeseen problems. Preventing the need for additional high costs or drydock when it is too late.
Hull mounted impressed current anodes have three major critical components. 1. The anode to supply cable connection and hull penetration 2. The dielectric shielding system 3. The active anode element and mounting The most important area here is the dielectric shielding system . This is applied to the area of the hull immediately behind and adjacent to the active anode element. In most systems this consists of two areas, a primary and secondary shield. The primary shield is usually a fiberglass or thermoplastic sheet that goes under the anode and extends about 1-2 feet (30 - 60 cm.) from the anode element in all directions. The shield is often mechanically fastened to the hull and a sealing/bonding compound introduced between the shield and the coated hull surface. The secondary shield is usually an area of high build epoxy or mastic coating that extends an additional distance 3-4 feet (90 - 120 cm.) beyond the primary shield. The integrity of this shield is critical if the CP system is to distribute protective current to all areas of the hull. Any damage to the shield will result in unacceptably high potentials on the exposed hull (if the anode is operated anywhere close to its rated current). This normally results in hydrogen evolution at the steel hull surface, which causes progressive disbandment failure of the shield to the point where the anode can no longer be operated. This area is virtually always in need of maintenance in between the 5 yearly dry dockings Anode elements can usually be designed to last as long as required, so the protracted design life may not be a problem provided that the dielectric shield holds up. Problems can however arise ,in this case FN Diving can replace any system underwater on the current market.
