Polishing of helices. Spend less fuel!

It is inevitable that the performance and fuel efficiency of any vessel will decrease over time, due to the wear of its engines or hydraulic parts. There are several factors that can accelerate this wear, being the rugosity of the propeller a common and important factor.

As the propeller fulfills its job of propelling the boat forward, the propeller is continually exposed to various underwater bio-chemical processes that are harmful. Among the most common processes we can mention: biofouling (marine growth), oxidation / corrosion, electrolytic action, erosion by cavitation, among others.

How does it affect the propeller?

This constant exposure contributes to the increase in roughness (according to ISO 484 a factory propeller must have between 1.5 microns and 6 microns of roughness) of the surface of the propeller, each day that passes this roughness increases, due to the aforementioned bio-chemical processes.

What are the consequences of this increase in roughness?

The roughness of the propeller has a direct relationship with the performance of the ship and the fuel efficiency, in fact, statistically speaking, a battered propeller can lead to a decrease in the vessel’s speed and power of up to 7%, as well as significantly increase fuel consumption, which in the end means a significant reduction in the competitiveness of companies, as well as profitability.

The increase in the roughness of the propeller implies an increase in the area of ​​the propeller, which causes a proportional increase in the friction between the surface of the water and the surface of the propeller, and therefore demands a greater power to the motor, demanding In turn, an accelerated fuel consumption (to overcome this increase in friction), accelerating the deterioration of the transmission shaft and shortening its useful life.

In Seven Seas, we have a highly trained technical staff and a body of certified and experienced professional divers to carry out the tasks of polishing underwater propellers, always aiming to achieve the highest quality finish possible following the reference Rupert scale, and ensuring, in addition, to maintain the roughness values ​​between the limits recommended in the ISO 484 standard.

Seven Seas uses a high-speed polishing system, designed for multi-stage polishing discs. The polishing process is simple and includes the polishing of the blades, polishing of the roots of the blade, cleaning and polishing of the protuberance of the propeller and the cone; It can be described in 3 stages:

I. First – The propeller is polished using a coarse-grained abrasive, this in order to remove all the incrustations of algae, weeds and shells.

II. Second – The propeller is subjected to a second polishing process using a very fine abrasive; This has the purpose of eliminating erosions and dents on the surface of the propeller. In this stage the propeller is polished carefully until reaching 2 microns of C.L.A., thus ensuring a smooth surface and without imperfections.

III. Third – In this stage depending on the condition of the propeller, a third polishing is used using a special pad, to achieve a C.L.A. about 1 micron, to obtain a smooth and smooth surface.