A clever feat of engineering

Successful conversion of Platform Supply Vessel to Walk-to-Work vessel

Interview with Marjan elderman - feenstra, Project manager Niestern sander

The Blue Queen arrived in Delfzijl from Norway in late 2017. This standard PX121 Platform Supply Vessel (PSV) then spent the next 12 weeks being whipped into shape by Dutch shipyard Royal Niestern Sander, working on behalf of Wagenborg Offshore. Converted into a dedicated Walk-to-Work Emergency Response and Rescue Vessel, the PSV – rechristened the Kasteelborg – was delivered on schedule in March 2018. It was a challenging conversion project in which time and planning played a major role. 

The docks at Niestern Sander are a beehive of activity: people come and go, cranes lift materials from the deck of the Kasteelborg, and there are hoses everywhere emptying the vessel’s tanks to prepare it for the upcoming stability trial. Marjan Elderman-Feenstra of Niestern Sander is the project manager and she’s overseeing the entire operation at the shipyard in Groningen. “Once it passes its stability trial, the Kasteelborg will be able to leave the shipyard,” Marjan explains. “We can then look back on a clever feat of engineering. It was our job to convert the vessel from a standard offshore supply vessel into a special Walk-to-Work vessel with all sorts of extras - and that in only 12 weeks.” She points to an accommodation block behind her with an Ampelmann gangway. “We started building the various structures before the supply vessel had arrived, for example this extra accommodation block and the foundations for the cranes and gangway.”


“Niestern Sander is one of the few seafront shipyards that has both a repair division and an engineering division.”

Niestern Sander is one of the few seafront shipyards that has both a repair division and an engineering division. This unique combination gives it a considerable edge in vessel conversions. It has already completed a number of successful conversions, for example the Pacific Orca, the Harriet Explorer, the Redsborg and the Arctic Sunrise. “During the engineering phase, we already began building the new sections and structures and ordering the various materials we’d need,” says Marjan. 

 “We also prepared for the vessel’s arrival in late December by going over the project in detail with our local subcontractors. Niestern Sander is the pivot of the whole operation. We’re the main point of contact for clients and we subsequently instruct our project subcontractors, in this case Eekels, De Haan and Wolfard & Wessels. We decide together, in advance, how we’re going to tackle the project and what the duties and responsibilities of each party are. That way we all know precisely what we need to do.”



When the vessel arrived at the docks in late December, the clock began to tick. “We knew that the vessel had to ready to sail by 1 March and that we had a lot of work ahead of us. We put about 80 of our employees on the project and worked flat out. At first it rained all the time and we were in danger of falling behind schedule. Then it got really cold. The wind chill was -18 C. Despite everything, we still managed to completely transform the vessel. It has a new accommodation block with sanitary facilities. We installed an Ampelmann gangway, a crane with a new foundation, and a completely new HVAC system. We also placed a daughter craft on board, attached hose reels on the port side and built all sorts of new pathways and landings,” Marjan sums up. 

“I’m delighted that we managed to get all this done in such a short timeframe.”

“If you ask me, the secret to our success is the commitment shown by our employees. The whole vessel shines with their pride and skill. And I’m delighted that we managed to get all this done in such a short timeframe,” concludes Marjan.