The use of the first metal nail, used in the construction of a sailing ship, gave rise to the constant and unceasing struggle of a person with the process of metal destruction - corrosion. Over the centuries, with the increasing presence of metal parts of the case and mechanisms, the problem of anti-corrosion protection has grown to a critical scale.
A vessel afloat, in the process of interaction with seawater, which is very aggressive, undergoes chemical, galvanic and electrolytic reactions. The build up of rust, which as a result of these phenomena covers the metal parts of the yacht, not only spoils the appearance of the vessel, the problem is that the metal loses its properties, collapsing in the process. Methods for neutralizing, or at least slowing down the natural corrosion process, have become the subject of close study by scientists.
During the operation of sailing ships, the main methods of combating corrosion, available in practical use, were derived. A commonly used method of coating metal parts, cleaned from rust, with a layer of primer, varnish or paint. Non-metallic plating has also proven to be successful. Today, metal coating with a layer of another metal, with higher anti-corrosion properties, is increasingly used. Zinc protection, for example, is used quite actively in the construction of yachts. Preservation of the vessel from rust requires knowledge of various types of corrosion, the ability to identify and eliminate them.
Oxidation, or simply - rust, occurs in the process of metal contact with humid air. The surface layer of aluminum oxide, covering the aluminum parts of the yacht hull, also tends to deteriorate under the influence of salt water.
As noted by specialists 2yachts, in such situations, the best way to avoid possible corrosion of metal parts of the case and mechanisms, will carry out regular work on applying a primer to cleaned surfaces, followed by painting problem areas.
This type of corrosion occurs as a result of an electrochemical reaction, during which current flows between two different metals. Let's say a ship with aluminum composite hulls is moored to a pier with steel supports. Both the ship and the pier pillars are in salty sea water, an excellent natural conductive solution. In such a situation, steel (a less active metal) becomes the cathode, and aluminum, respectively, the anode. The process of leakage of electrons of aluminum through salt water to the cathode begins. The end result of the reaction is the dissolution of aluminum. Galvanic corrosion occurs imperceptibly, and its manifestations can appear after a long time, calculated in weeks and months.
Application of zinc coating will be excellent protection. Zinc, as a more reactive metal, acts as an anode, using up itself, but saving the aluminum of the body. At the same time, measurements carried out in the most popular yacht parking areas showed a dangerous concentration of harmful toxic substances released during the destruction of zinc. The problem is still under development, but already now, the proposed aluminum alloy anodes have become an alternative to zinc.
Like galvanic corrosion, this current can cause serious damage to subsea fittings. It does not arise from the contact of two dissimilar metals, but from the poor condition of the yacht's wiring, wiring on a nearby boat or in the dock. In this case, the destructive action occurs in a matter of hours.
In order to avoid the occurrence of corrosive current, it is necessary to constantly monitor the cable connections and the condition of the electrical circuit of the vessel, eliminating damage, with the obligatory replacement of worn out waterproof insulation, especially for those handed over to yacht charter, as they have increased reliability requirements. All types of corrosion create many problems, but based on the foregoing, preventive maintenance on a yacht will help keep the boat in perfect condition for a long time.
Periodic treatment of the bottom of the yacht, timely replacement of used anodes, maintenance of electrical wiring and batteries in proper condition are simple but necessary requirements. Cleaning and replacement of rusted elements, as well as painting with fresh paint, the utility skipper carries out without any instructions, taking care of the cleanliness and dryness of the deck.