A 24-month trial of a hull coating containing the bio-repellent active agent Selektope on a 46,067 dwt chemical[ds_preview] and products carrier has confirmed the antifouling ingredient’s hard fouling prevention power. Selektope is an organic, non-metal compound that works to prevent barnacle fouling by temporarily activating the swimming behaviour of barnacle cyprid larvae, making it impossible for them to settle on the hull. It is characterized by high efficacy at extremely low concentrations (0.1% w/w), is ultra-low leaching and offers paint manufacturers the flexibility to boost copper-based paint formulations or replace copper completely, the developers say.
In 2015, the vertical sides and flat bottom of Laurin Maritime’s vessel »Calypso« were fully coated with a coating containing Selektope during its first five-year drydock. The vessel has spent two years in active operation across a wide range of trade routes, with more than 50% of operating time spent in biofouling hotspots with > 25 °C (up to 32 °C) temperatures.
According to Selektope, independent hull and propeller performance analysis has verified that after 24 months »Calypso«’s increased total resistance was calculated to be 7%, compared with a benchmark new vessel that would see an increase in resistance of 10–20%. Over the period, speed losses amounted to a mere 2% when measured against sea trial performance. Data also confirmed that the development rate of added resistance for »Calypso« amounted to 0.1% (0.5% to 1.5% is expected).
A recent underwater hull inspection established that »Calypso«’s hull is very clean, with divers finding no soft or hard fouling over the starboard and portside verticals, flat bottom and bilge areas.
Laurin Maritime’s technical director Bertil Andersson says: »The vessel has now operated for two years since last dry dock, and we can conclude that the fouling of the hull (read added hull resistance) remains at a very low level and the trend continues being flat.«
