DNV has launched the world’s first class notation for offshore wind turbine installation units. The market for wind turbine installation units is growing rapidly as the offshore wind industry picks up pace. The classification of these units is based on DNV’s Offshore Service Specification DNV OSS-101 “rules for classification of offshore drilling and support units”, which was originally developed for classifying drilling and production vessels used in the oil & gas industry. Wind turbine installation units may be column-stabilised, self-elevating or ship-shaped units that are tailor made for the installation and maintenance of fixed and floating wind power equipment. They are designed to install the different equipment, such as foundations, columns, generator houses and blades, piece by piece by crane lifts or in one operation using lowering techniques. The new class notation, which will serve as a recipe for how to class wind turbine installation vessels, is currently being piloted and is expected to be added to DNV OSS-101 by October of this year.