Most people are familiar with corrosion due to the visual aspect that it leaves behind. With superficial corrosion on the exposed superstructure leaving stains or bubbling of the paint, and the degradation of installed sacrificial anodes. The invisible danger though lies in the corrosion when it is not directly spotted and causes unexpected damage resulting in more unforeseen expenses during maintenance, or worse, the sudden system failure during the critical charter season, ending with an emergency trip to a yard to rectify corrosion that could endanger the vessels operation.
Galvanic corrosion is an invisible danger that slowly creeps up in all parts of the vessel. Protecting your vessel against the inevitable effects of electrolysis does not have to be a headache, but if left unchecked will certainly hurt the wallet.
Various techniques are available to prevent corrosion, but unless a clear study is made of the vessel, you may yourself having invested in solutions that are not the right one for the problem that you have. A pre-emptive study will help in choosing the right solution to not only save on budget spending, but also considerably reduced vessel downtime.
Piping is a major component that is subject to corrosion. This includes fresh water and salt water pipelines, as well fuel and gas lines. Any two metals that is exposed to a fluid between them can create potential electrolytic cells if left unchecked.
The basic principle of corrosions requires that the following conditions are met.
- Electrochemically dissimilar metals must be present
- These metals must be in electrical contact
- The metals must be exposed to an electrolyte
In some forms of corrosion, there is almost no visible weight change or degradation, yet properties change and the material may fail unexpectedly because of certain changes within the material. Such changes may defy ordinary visual examination or weight change determination.
One may wonder why so much attention is drawn on galvanic corrosion, but in a modern vessel which requires high reliability and minimum downtime, a successful operator cannot tolerate major corrosion failure, especially those involving personnel injuries, fatalities, unscheduled shutdowns and environmental contamination. For this reason, considerable efforts are generally expended in corrosion control at the design stage and in the operational phase.
Corrosion can lead to failure in plant infrastructure and machines which are usually costly to repair, costly in terms of lost or contaminated product, in terms of environmental damage, and possibly costly in terms of human safety. Decision regarding the future integrity of a structure or its components depend upon accurate assessment of the conditions affecting its corrosion and rate of deterioration. With a proper analysis made by clear inspection procedures following ISO standards, an informed decision can be made as to the type, cost and urgency of possible remedial measures.
Atlante Marine Solution has placed great effort in its research and development department to enable the clear identification and sensible reporting of the specific conditions found on each vessel. The specific tools created has enable that inspections can happen with the minimal interruptions to the vessel operations and enable a clear and defined maintenance schedule be established.
The required level of maintenance can vary greatly depending on the operating environment. While some infrastructure may only require regular repainting and occasional inspection, other areas will require greater vigilance such as tubing and critical operating equipment which will need a more extensive maintenance schedule.
Even the best designs cannot be expected to anticipate all conditions that may arise during the life of a vessel. Corrosion inspection and monitoring are used to determine the condition of a system and to determine how well corrosion control and maintenance programs are performing. Traditional corrosion inspection practices typically require planned periodic shutdowns or service interruptions to allow the inspection processes. These scheduled interruptions may be costly in terms of productivity losses, restart energy, equipment availability, and material costs. However, accidental interruptions or shutdowns are potentially much more disruptive and expensive.
It is the belief of many that corrosion is inevitable foe that should be accepted as an inevitable process. Actually, something can and should be done to prolong the life of metallic structures and components exposed to the environments. As products and manufacturing processes have become more complex and the penalties of failures from corrosion, including safety hazards and interruptions in vessel operations, have become costlier and more specifically recognised, the attention that is given to the control and prevention of corrosion has increased.
Studies have shown that corrosion cost can be divided into two areas:
- The portion of total corrosion cost that could be avoided if better corrosion control practices were used; and
- Costs where savings are achieved through the use of new and advanced technology.
Potential savings and recommendations in terms of ways to realize savings from corrosion damage that Atlante has defined as the most suitable for superyachts include
- Better dissemination of the existing information through education and training, technical advisory and consultancy services, and research and development activities; and
- The opportunity for large savings through more cost-effective use of currently available means to reduce corrosion.