Coating protects rudder of icebreaker tug

The m/s Jääsalo is responsible for keeping the Veitsiluoto fairway open in the port of Kemi in Finland.

The Bothnian Bay usually begins to freeze in October-November and the last of the ice melts away by the beginning of June at the latest. Since the channel is narrow, shallow (7 m), and winding, large icebreakers are unable to open it. Navigation in the Bothnian Bay during the icy season is therefore made possible thanks to the icebreaker tug Jääsalo.

The decision to use Ecospeed on the rudder of the vessel was made by the shipowner after cavitation damage had appeared. Ecospeed will prevent similar damage from occurring again and ensures lasting protection for the remainder of the vessel’s service life.

If a rudder is not given the proper protection against cavitation and the resulting erosion and corrosion damage, the financial consequences can be substantial for the owner.

The coating equally provides the rudder (and the entire underwater hull) with an impenetrable protective layer while its flexibility enables absorption of the forces that are produced by cavitation.

Tests conducted in a flow channel have confirmed that Ecospeed performs extremely well under severe cavitation. These tests were divided into six stages during which the coating was exposed to an increasing pressure drop, creating a growing cavitation force. Even after the last stage no erosion was present on the test patch coated with Ecospeed. The tests were organized by the French Ministry of Defense and were carried out in Grenoble. These test results have been borne out repeatedly on rudders on many different types of ships.

Together with the rudder, the ice belt of the Jääsalo was coated with Ecospeed. This is the area on the underwater hull most prone to mechanical damage from sailing through and breaking ice. On the bow the ice belt can extend to about 1m above the waterline. Ecospeed has received the Lloyd’s Register certificate that recognizes the coating as an abrasion resistant ice coating. This allows owners of newbuild vessels intending to navigate in ice conditions to reduce the thickness of the plating of the ice belt as long as this area is coated with Ecospeed.

The owners of m/s Jääsalo also coated the entire stern area with Ecospeed and are planning to have the remainder of the underwater hull of the icebreaker tug coated with Ecospeed later this year, to give the entire underwater part of the vessel the same lasting protection against ice.