Fangst; diving inspection of ultrasonic protection of hull of Norwegian fishing vessel

The vessel

The Fangst is a 14 meter Norwegian fishing boat. It is active in the North Sea and the Barents Sea.

Norwegina fishing vessel Fangst in harbour

Fishing vessel Fangst










The ultrasonic system

The Fangst has been equipped with 2 control-units HDS20. That makes 4 transducers all together. The transducers are evenly spread, glued on the inside of the hull. The ultrasonic systems were installed September 2015. The transducers are 50 Watt. Presently, Shipsonic uses 100 Watt and 120 Watt transducers. The Fangst is not equipped with box-coolers, but with cooling-pipes mounted outside along the hull.

HDS20 (2transducers)








Diving inspection of effectiveness after 2 seasons


The video shows the hull to be exceptionally clean. The owner informed us that before installing the ultrasonic system, after 2 seasons in the water, the hull would be completely covered in a thick layer of mussels.

Drydock inspection of effectiveness after 3 seasons

Difference in fouling of hull and cooling-pipes

Difference in fouling between hull and cooling-pipes

Mussel growth on less protected areas








Propeller and rudder of Fangst

Propeller and rudder of Fangst


After 3 years the Fangst went into drydock. Also here the photos show a good result. Only the cooling-pipes have some growth. The cooling-pipe units are mounted on the hull with brackets. This isolates the cooling-pipes form the ultrasonic waves traveling through the hull. A solution would be to install transducers directly on the cooling-pipe units, on the inside. The difference in fouling of the cooling-pipes is because some are low temperature (LT) and some are high temperature (HT). Just as with box-coolers, the HT’s do not need anti-fouling. Rudder and propeller have no marine growth.





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