Combat Support Ship Den Helder prepares for warm-weather sea trials and royal designation

The Combat Support Ship Den Helder has been christened and handed over, but that does not mean the project is completely finished. In recent months, a great deal of work has been done to resolve outstanding issues from the first sea trial and to carry out the final phase of the project. In addition, the new replenishment ship made its public debut during the World Port Days in Rotterdam, and several sea tests were conducted, such as trials of the helicopter deck for incoming helicopters.

“During the voyage to Rotterdam, we identified a few more outstanding points, and we managed to further reduce the number of issues still open,” explains Damen Naval Project Director Arjan Risseeuw.

The coming weeks and months also feature a full schedule. On 1 October, the ship will be commissioned and will officially receive the royal designation Zr.Ms. (HNLMS)  before its name. On 5 October, the ship will depart for new sea trials in the Caribbean for the warm-weather tests. Arjan: “The ship has not yet been transferred to the Commander of the Royal Netherlands Navy (CZSK); that will only take place in March next year. But with the upcoming trials, the royal designation makes it easier to classify the ship while at sea.”

He continues: “For the warm-weather trials, the CSS will first spend two weeks at sea before docking in Curaçao, where our team will embark. After a week in port, the ship will operate at sea for another two weeks. This gives us the opportunity to test the systems under high ambient temperatures and humidity, and to see if nothing overheats. We also hope to identify a few more outstanding issues and carry out some Sea Acceptance Tests (SATs).”

The warm-weather trials will be followed in early 2026 by cold-weather trials, when the CSS sails to the Gulf of Bothnia between Sweden and Finland. There, the ship’s performance will be tested in icy conditions, and alongside Damen Naval’s SATs, the navy will conduct its own tests, such as various sound measurements.

“A lot of work has been done in recent months, and there is still more to do, but the ship is performing well and feels reliable when we are at sea,” says Arjan. According to the schedule, the ship will be handed over at the end of March 2026 by the Command Materiel and IT to the Royal Netherlands Navy, at which point the CSS will officially enter service.