Hydrex Underwater technology

Last month the rudder and the ice belt of the harbor icebreaker tug Jääsalo were coated with Ecospeed in Naantali, Finland. The m/s Jääsalo is responsible for keeping the Veitsiluoto fairway open in the port of Kemi in Finland.
 
The Port of Kemi in the Bothnian Bay is an excellent import and export harbor for the industry of the Barents Region. The harbor represents the fastest route to the northern areas of Finland, Sweden, Norway, and the Murmansk area in Russia.

Nearly 750 vessels visit Kemi each year, with relatively equal distribution throughout the year. The vessels carry about 3 million tons of goods. It is therefore extremely important that the harbor is able to offer its own icebreaker services to vessels.

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.

Best possible rudder protection
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 rudder must be protected from the damaging effects of cavitation. Ecospeed gives a very thorough and lasting defense against cavitation and corrosion damage for a ship hull’s entire service life. 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. This prevents the damage normally caused by this phenomenon.

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.

Easy application
The newbuild phase is the perfect time to apply Ecospeed, but the coating can also be used to protect vessels that have been in service for some time and are already facing cavitation and corrosion damage.

Ecospeed’s flexibility makes it easy to adapt the application schedule to the rest of the activities scheduled at the shipyard or drydock in a way which does not interfere with them. Overcoating time can be as short as three hours, which means that for smaller surfaces such as rudders, propellers or bow thrusters the two coats required can usually be applied in a single day.

Certified abrasive resistant coating
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 1 meter 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.

Icebreakers and ships that trade in icy waters have their own very specific problems when it comes to protecting their underwater hull. Icebreakers have to use their weight to ram into thick ice and force a passage. Ice going ships, such as those trading in the North Baltic, the northern coasts of North America, the Great Lakes, and so on, are constantly being hit by chunks of ice which may be 50 centimeters or more in thickness. Not only is the ice highly abrasive, there is the additional factor that the steel of the hull flexes under the impact. When the metal sheets that form the hull flex and bend under the impact, the paint that is supposed to protect them does one of two things. It either is flexible and adheres so well to the metal that it is virtually part of the steel itself and thus survives, or it is less flexible than the hull and cannot flex with the steel, in which case the paint gradually, or not so gradually, is forced away from the hull and rubbed away under the impact. It is a problem which is unique to ships faced with ice impact.

Ecospeed demonstrates excellent attachment to the hull and successful resistance to extremely icy conditions. Ecospeed has proven its ability to withstand the harshest winter conditions on numerous occasions. For over seven years several vessels coated with Ecospeed have been sailing the most northern parts of the Baltic Sea during the winter season and as far as both the North and the South Pole. These vessels’ underwater hulls frequently have to endure the impact of large pieces of floating dry ice. Despite this, there has been neither damage from the ice nor any deterioration of the coating and none of these vessels have required more than just a few touch-ups during their drydock visits.

Summary
Due to its unique composition, when it comes to icebreakers and ice going vessels, Ecospeed is not only the best protection available for underwater hulls, but also for the rudder or any other part prone to cavitation damage. The coating can keep the underwater part of any vessel safe for the entire length of its sailing life.