Shipping has been identified as the most efficient mode of transport to face the demand of increased globalization of trade when compared to its land and air alternatives. To face these demands vessels are made to follow appropriate measures to work efficiently and reduce downtime as a result of this raising need for transport resources with the increase of globalization.
Consequently, the classifications society has taken a particular interest in making sure all the vessels follow the regulation of safe sailing and efficient working. The crux is to give prominence to underwater cleaning which includes underwater maintenance of the hull, Propeller Polishing, Rudder Repair and so on.
The Importance of a Clean Propeller
Vessels or structures that partially reside below the surface of seawater or freshwater are subjected to various levels of fouling by marine or aquatic organisms, respectively. At the base of the fouling mechanism for vessels and structures residing in sea or freshwater are biofilms formed on such structures, which constitute the glue between marine or aquatic organisms and the actual structure.
The biofilms form and the fouling organisms attach to all subsurface structures, such as propellers, rudders, inlet and outlet ports, sonar housings, and protective grills which slows a vessel’s working efficiency.
A vessel without a clean propeller or hull is most likely to be prohibited from entering water territories owned by different Nations thus underwater ship propeller maintenance is an important factor that cannot be taken lightly.
Reasons For The Increase In Propeller Roughness
While the concern is the efficiency and hence the fuel consumption for the shipping industry, the effects of roughness on the propeller cavitation are important for the vessels and the possible impact on marine fauna.
The effects of propeller and hull roughness, including fouling, are known to affect the performance of a vessel, especially as measured in additional fuel consumption and less so, the number of voyages attained in a lifetime. Today there is significant attention given to hull surface cleaning, coating and propeller polishing to address these issues.
The roughness of the propeller and hull can occur due to a number of factors including hull material utilized and quality of construction, mechanical damage in operation, fouling, roughness from paints and coatings and their method of application, damage to the coating during maintenance, corrosion and pitting of the hull structure material, as well as biofouling influenced by the type of antifouling paint or coating and method of application.
The effect of the different roughness levels on the thrust, torque, efficiency, and cavitation patterns of the propeller for various operating conditions should be explored, and appropriate solutions must be used.
Methods Used For Propeller Cleaning
Various cleaning methods and devices applied to dry-dock cleaning and underwater hull cleaning are introduced in detail, including rotary brushes, high-pressure and cavitation water jet technology, ultrasonic technology, and laser cleaning technology. The application of underwater robot technology in propeller polishing or cleaning not only frees divers from engaging in heavy work but also creates safe and efficient industrial products.
Many underwater cleaning companies offer underwater ship propeller maintenance which includes propeller cleaning and propeller polishing all while without dry docking. It is necessary to carry out underwater maintenance at regular intervals.
During drydocking the propeller receives the treatment consisting of a high-pressure seawater wash, hand scraping, hand polishing by wire brush machine and a coat of grease to protect from hull painting; removing all effects of fouling and correction in surface roughness.
Propeller Super Polishing is more complex and effective than simple propeller polishing, propeller super polishing enhances the quality and health of propellers significantly and it should be undertaken once every six months to ensure that your vessel is in the most optimal condition possible. Hydraulic hand motors fitted with various coarse ‘’3M’’ polishing pads are used for propeller super polishing.
Underwater maintenance is crucial for the safety of your vessel and your crew. Regular underwater cleaning helps to improve efficiency, save fuel, and cuts down on expensive repairs over time. Inspection and maintenance are critical to the performance and longevity of underwater structures. It is important to undertake regular underwater propeller maintenance once every six months or twelve months.
Nereus Subsea has an excellent track record of carrying out propeller cleaning exceeding all requirements. We will deliver everything you need to ensure your vessel stays compliant with international regulations when entering international waters.