Corrosion: Main Problems in Naval Architecture - Essay Sample

Introduction

Naval architecture, also known as marine engineering is a branch of engineering science with the art involving the layout of ships as well as boats. It is a broad discipline involving an insight of hydrodynamics, stable and unstable body motion, hydrostatics, the stability of components as well as the layout of structures. It comprises projection and estimates of all costs, future performance as well as all the sections of the ship.

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Main Corrosion Problems Faced by Ship

Corrosion is the deterioration and destruction of materials, for instance, steel rusting resulting from favorable factors in the environment. There are various types of corrosion classified according to their appearances. The first category is those determined through the naked eye examination. They include; crevice corrosion, galvanic corrosion, pitting, and general corrosion. The second group involves those identified through auxiliary diagnoses such as selecting leaching, chafe corrosion, erosion-corrosion, and inter-granular corrosion. Lastly is the category classified through the use of an electron microscope. Hydrogen bastion, stress corrosion cracking as well as corrosion fatigue falls under the group (Guedes Soares 2010).

Primarily, general corrosion results in the degradation of vigilant coating systems in the ship. The corrosive nature takes place uniformly in the surface area of the coating system slowly till the deterioration of the system. Galvanic corrosion refers to the destruction resulting from various metals or materials which are not similar are immersed in a corrosive electrolyte. The two metals submerged in electrolyte solution has a different reaction. Anode being the most reactive erodes at a faster rate. Contrarily, the less responsive metal cathode corrodes at a slower pace. Galvanic corrosion is the most threatening in the marine environment because ship structures involve different types of metals with varying kinds of reactions. Moreover, crevice corrosion results from the cooperation of some metal structures alongside other associated environments, for instance, confined part and a tight in the ship with a limited supply of oxygen. Due to less and different oxygen supply between the various environment in the system, cracking, or perhaps crevice, can develop, resulting in critical damages (Kulkarni, 2015).

Besides, inter-granular corrosion is another corrosion mostly affecting the ships. It refers to the contrast between two different parts of metal structures, for instance, the granular bodies and adjacent granular boundaries. Typically, intrusion correlates to the development of a composite in the confines, which decreases the layers and hence a metal surface that has lost the corrosion resistance erodes. Furthermore, stress corrosion cracking is another problem faced in marine engineering. The cracking accelerates typically as a result of connection influence between the corrosive environment and adjustable stress. Stress corrosion cracking results in more failure of tensile alloys. Some metals such as the stainless steel establish microscopic cracks visible through the use of electronic microscopy from tensile stress. Moreover, some of the structures could be forced perhaps to a contradictory direction.

Mechanism of Ballast Tanks Corrosion

A ballast tank is a supplementary compartment design and builds on the ship. It is an essential part of the vessel providing flexible stability or rather an equilibrium. Ballast tank corrosion refers to the degradation of its surface progressively until the tank steel cracks on its own. Particular corrosion type does affect ballast tank the most, for instance, pitting corrosion due to the influence and attack of microbiological as well as stress. Pitting corrosion results from the wreck of essential protective layers such as the oxides leading to a decrease in the concentration of oxygen and an increase in acid concentration, for example, chlorides. Moreover, the impurities in the metallic structures, for instance, the insertion of materials which are not metallic.

Pitting corrosion occurs in two forms, the active and inactive form. In the active form of corrosion, materials such as metals change their shape. It takes place in the presence of oxygen as well as a limited supply of oxygen. On the other hand, inactive corrosion is where the rate of corrosion is slow on the materials. The ballast tank has a coating system with an inactive protective layer. The corrosion and breakage of the protective film in the coating system result from the mechanical problems due to the presence of some pathogens.

The ballast seawater consists of microorganism which promotes the production of bacteria. "Iron plays an integral part in the metabolic process organism. In natural aerobic reactions, the ferric reacts with iron. Whereas, in anaerobic reaction, iron can directly react with metabolic products in a process known as the microbially influenced corrosion (MIC)." Microbially influenced corrosion easily identified through the observation of color ( reddish-brown) results from the aerobic reaction. Contrarily, the black substance, which is the deposits of corrosion activities result from the anaerobic reaction.

Due to anaerobic reactions in the ballast tanks, it is challenging to identify pitting formation, hence slowly deterioration of steel materials in the ballast tanks. Pathogens, for instance, Sulphate Reducing- Bacteria (SRB), are the catalyst in the anaerobic atmosphere. To sum up, ballast tank corrosion results from mechanical damages as well as the aerobic and anaerobic reactions. Microorganism acts as the catalyst, speeding the reactions, hence the degradation of materials structure in the ballast tank.

Short-term and Long-Term Effects of Ballast Tanks Corrosion on the Ship

Ballast tanks corrosion has several impacts on the ship. Some are short term, while others are long-lasting effects. The corrosion of the ballast tank destroys the seals on the ship. Destructions of the seals perhaps might allow water into the electrical connection box and other machinery in the ship. The entrance of water leads to the destruction of mechanical connections resulting in short circuits. Furthermore, wearing out of the seals leading to the entrance of water might cause some stability issues in the ship. A lot of water in the ballast tanks makes the loose vessel balance, which might cause havoc accidents. The corrosion of the ballast tank destroys and weakens the riveted joints, which might cause flooding in the ship (Kazuhiko & Nakamura 2015)

Moreover, the deterioration and damages of resistance steel material in the upper part of the ballast tanks might reduce the life span of the ship, which is approximated to be 25 years. Anaerobic reactions are responsible for the wear outs and deterioration of the steel materials, which corrodes slowly over a long period, microorganism in the seawater acts as the catalyst in the reactions. The weakening of some structures in the ballast tanks due to mechanical vibrations perhaps might lead to the entrance of impurities as well as dirt, which in the long term results in significant damages and failure in operation (Schweitzer 2007). Lastly, the ballast tank is, and the entire 90% of the ship is made up of steel materials. The wearing out and the destruction of the steel has a high impact on the operational cost of the marine ships. Steel materials are costly; hence the regular replacement might require additional costs affecting other operations in the ship.

Problems That Can Arise Concerning Watertight Integrity of the Vessel

Watertight integrity refers to the prevention of water passage into and out of any vessel, for instance, naval ship. Watertight integrity can be damaged through various actions such as the severe damages from the storm, the collisions as well as the failure to follow the restrictions about watertight integrity. Various problems can arise concerning the watertight integrity of the vessels. Primarily, the gasket damages, deterioration, and cracks are one of the significant challenges facing watertight integrity resulting from contraction of the gasket in the junctions hence leakages. Gaskets should not be disclosed to the agents, causing the destruction such as rust, heat, or some liquids, for example, grease.

Secondly, the broken, sloppy, and missing parts is another problem concerning the watertight integrity. Loosen, and damaged parts allow the penetration of water into the vessels. Careful measures should be taken into consideration when operating the watertight doors. Additionally, deterioration, distortion, and breakdown of metal surfaces due to rust and other mechanical problems result in water leakage. Proper maintenance of the delicate parts of the vessels should be taken into consideration for the efficient functioning of the vessels (Kyokai 2007). Moreover, the wearing out of the hinge pins and unprotected pins is another problem facing the watertight integrity. The pins have to be checked regularly and appropriately protected to rule out any form of leakage completely.

Missing of significant watertight wrenches, for instance, the engineers' wrenches, the dogging wrenches as well as the t-wrenches are some of the additional challenges concerning the watertight integrity in the vessel. Proper and sufficient tools ensure smooth and excellent operational maintenance of the vessels. Furthermore, the less secured and protected openings might expose ships to dangerous incidents as a result of flooding. Other problems might be problematic operations of the crew, for instance, difficulties in identification and accessing of weathertight closures. Damaged spring clips are also considered as another operational problem in watertight integrity.

Besides, random inspections to ensure that all the watertight doors, together with other parts of the vessel, are in proper condition, is another challenge. Lastly, insufficient funds, fewer spare parts, labor sums up the issues related to watertight integrity. Marine technicians are task at ensuring adequate inspection and should be provided with enough funds as well as proper tools and spare parts.

Overview of the Current Methods Employed in the Prevention and Treatment of the Ballast Tank Corrosion

Corrosion is progressive damage and deterioration of a substance through some reactions and specific agents taking part in speeding up the reaction. To counter the problem, many ways of treating, controlling, and preventing corrosion do exist. The most common ways of preventing corrosion in the ballast tank are through coating and paints as well as cathode protection. Principally, coating refers to the application of layer on the surface of a material or an object to prevent it from external damages. On the other hand, paints refer to a particular liquid with coloring characteristics, which provides an additional protective layer on the surface of material upon its application (Jotun 2001)

Paints are mostly used in the coating of objects and other materials to provide prevention against corrosion. Paints function in various ways of preventing corrosion. Some of the functions include the development of a barrier against any attack, decrease any form of reaction accelerating corrosion, and the provision of galvanic effects. The paints act as the barricade between the atmosphere surrounding the material and the material itself. According to Tezdogan and Demirel ( 2014), paints with chemical reaction effects incorporate inhibiting coloring, for instance, zinc phosphate, which prevents corrosion.

Moreover, the galvanic effect is more useful in preventing ballast tank corrosion since it contains some chemical elements such as pure zinc. Zinc element reacts...