Ocean

Ship Corrosion: Electric Shock Instead of Toxic Paints

You love ship hulls, barnacles and mussels. And if you’ve won a hull, then the resistance in the water enormous, and therefore the fuel consumption increases. But who has the idea of these teases with electric shock instead of fighting with toxic paints?

Engineers of the East German company Bioplan in Rostock and the Fraunhofer Institute, managed to spoil the docking to boat hulls the barnacles and mussels thoroughly with a special varnish in combination with supply voltage. The coating consists of three layers, through which flows a weak direct current of 0.1 millionaires (mA) per square centimeter.

Successful test series: ships free of vegetation

And the power supply voltage ensures that ships stay free of vegetation in first long-term tests even though they have long waiting times at the port to the parts. Just then mussels and barnacles with fondness settle. No small thing is to prevent this: much of the power by the friction of the water on the ship’s hull is lost in shipping, container ships, there are 40 to 50 percent.

What is the brainchild of engineers? The outer layer acts even as anode, another time, when the flow direction reverses as the cathode. At the anode, oxygen and chlorine through electrolysis resulting from the salt water. This makes the water in the vicinity of the hull mad what do not like barnacles, mussels and other potential settlers.

You can get also not used. Reverse of the current direction produces hydrogen, which compensated for the acid? After an alkaline environment adjusts itself. The constant change creates a pH stress, which prevents the establishment of micro-organisms.

Power is turned on only in the port

“When a 20,000-ton ship a peak power enough for 20 to 25 kilowatts”, says Uwe Spohn from the Microstructure Fraunhofer Institute  of materials and systems (IMWS) in Halle an der Saale. The protection is only necessary if the ship in the Harbour, so that keeps the energy consumption within limits.

The IMWS has refined a technique developed by the company bio plan from Ostseebad Nienhagen. Tested she is currently on a patrol boat of the fisheries control.

In fresh water, a higher voltage is required

For the time being, the technique only in sea water, which contains enough salt for the electrolysis works. A voltage of three to five volts enough to prevent fouling. “In fresh water also”, Sanchez says. “However, we need a higher power.”

Today used mainly anti-fouling agents, which prevent vegetation through the secretion of toxic substances. “With our system, we protect the vessels from vegetation, water from toxic substances and climate before unnecessary emissions”, says Professor Ralf B. Wehrspohn, head of the IMWS.

Sulfur remains a problem

Fouling is a massive problem for the shipping industry. Strong growth can increase fuel consumption by 40 to 80%. As much pollution and carbon dioxide emissions increase then. In particular sulphur is to create the environment, because ships may use still sulphurous fuel in the high seas. “We can use our expertise for other products as well, because anti-fouling systems play an essential role in the refrigeration and air conditioning, as well as drinking water treatment,” says Spohn.