DESS Aquaculture, a joint venture between Solstad Farstad and John Fredriksen’s Marine Harvest, has signed up to install Optimarin ballast water treatment (BWT) systems on its four new wellboats.

The 3,500-cbm newbuildings are due in 2019 and 2012 from the Sefine yard in Turkey.

Optimarin has sold 50 such systems this year, with Besiktas Shipping, Eureka Shipping, Solvang, Koyo Kaiun and Ahrenkiel also buying the kit, among others.