Ship ballast tanks can represent corrosion control nightmares. Ballast tanks are one of the most costly areas in which to apply coatings in both new ship construction and ship maintenance. Being subjected to intermittent wet and dry cycles of aerated sea water places extreme demand on corrosion control methods. Harsh service environments are coupled with necessarily complex tank geometries, where weight and hull designs dictate small, irregular tanks with difficult accessibility.
The life span of a vessel can be determined with the first coating application within the ballast tanks.
After the paint goes on, it’s too late!
Surface Preparation is therefore extremely important at both new building and during “in service” maintenance.
It is critical that whoever is carrying out this work has a thorough and well thought-out plan and is able to execute it in a professional manner.
AlfaTest can help you plan and oversee your ballast tank refurbishment!!
Things to think about when planning:
Budget
Choose the best possible method to suit your budget. Don’t try to do too much if the budget won’t permit. It’s better to get one tank done correctly than three tanks that you’ll have to worry about again in 3 years time.
Access
Can the job be properly carried out at sea with riding squads or does the ship need to be docked?
Will manholes be accessible? Can cargo be sufficiently protected?
Method of Surface Preparation
Deciding the most suitable type of preparation will depend largely on the size of the scope of work, as well as the surrounding factors.
For example; necessity for constant cleanliness, cargo cosiderations, time between or in ports, availability of professionals, supply of compressed air or fresh water… the list can be long and should be discussed with professionals before a decision is made.
Temperature and humidity
Where will the vessel be? Will it be necessary to use de-humidifiers or will normal ventilation be enough?
Coating technology has produced moisture tolerant products which are ideal for ballast tanks applications
Choice of Coating
All good coating companies have products suitable for ballast tank refurbishment. During a coating project it is very important to consult the coating company to get the correct product.
Make sure that a coating specification with surface preparation requirements, recoating intervals, drying times and ballast fill standby time after final coat is produced. Be sure that the chosen method of surface preparation has the capability of achieving this standard.
Use the coating company’s representative to check that the surface preparation and application of their product is within the specified tolerances so that you as an owner can expect a guarantee from both applicator and coating company.
