Norwegian shipyard Havyard has revealed it was Denmark's Esvagt that ordered two firm windfarm service vessels last week.
The company said the ships will be the sixth and seventh it has built for the owner.
Delivery is set for the third quarter of 2020 and the first three months of 2021. There is also an option for a third.
The vessels form part of a long-term contract with the Danish wind power company MHI Vestas and will work off the Netherlands and UK.
