On 27th November 2018, the engines of OOS Serooskerke were started. The OOS Serooskerke is being built in China Merchants Heavy Industries (Jiangsu). The vessel building contract is effective since 5th August 2016. After 10 months of engineering, the steel was cut on 28th June 2017. The engine start up would not have been possible

The OOS Walcheren is the 3rd vessel using the asymmetric brace-less semi-submersible design within the OOS family. The first is the OOS Gretha, currently operating in Brazil, and the 2nd is the OOS Serooskerke, which is under construction and due for delivery in Q3 2019. A total of 28 sub blocks are being keel layed. The weight of each