HNLMS Den Helder Combat Support Ship

HNLMS Den Helder is a new combat support ship (CSS) being developed by Damen Schelde Naval Shipbuilding (DSNS) to support multiple naval missions of the Royal Netherlands Navy (RNLN).

Vessel Type

Combat support ship


Damen Schelde Naval Shipbuilding (DSNS)


Royal Netherlands Navy (RNLN)




HNLMS Den Helder is a new combat support ship (CSS) being developed by Damen Schelde Naval Shipbuilding (DSNS) to support multiple naval missions of the Royal Netherlands Navy (RNLN).

The CSS will operate alongside the joint support ship (JSS), HNLMS Karel Doorman. The vessel will have the capability to operate in high threat situations when protected by frigates. It can also be used to prevent drug trafficking, control refugee flows and support emergency aid missions.

Combat Support Ship (CSS) development details

The procurement decision for the project was announced by the Dutch Government in December 2019. DSNS signed a contract with the Defence Material Organization (DMO) for the construction of HNLMS Den Helder vessel in February 2020. It will supervise the project along with the DMO.

Damen shipyards in Romania will undertake the construction of CSS, while the final outfitting will take place in Damen Shipyards Den Helder.

Scheduled to be delivered in the second quarter of 2024, the ship is expected to become operational in the second quarter of 2025. The CSS project is estimated to cost €375m ($445m).

Design and features of HNLMS Den Helder

Based on the design of Karel Doorman, HNLMS Den Helder will be approximately 180m-long and will have a displacement of 22,400t. It will mainly supply fuel, ammunition and goods to other naval vessels at sea.

The vessel will have the capacity to accommodate a total of 150 personnel, with 75 crew members and 75 additional people on board. It will also offer space to house two helicopters and up to 25 containers on the upper deck.

The efficient design integrating an optimal combination of advanced diesel engines, propellers and hull shape will reduce fuel consumption by 6% when compared with HNLMS Karel Doorman.

The support ship will be fitted with hydraulically operated shell doors and covering hull doors for providing access to gangway and shore. A top-hinged elevator door and container hatch will also be fitted aboard.

The energy management system will enable the control of power generation and distribution systems. It will also ensure the availability of electric power across the ship.

The vessel will be fitted with a Scout Mk3 surveillance radar and an identification friend or foe (IFF) system.

HNLMS Den Helder propulsion

The combat support ship will be powered by four Wärtsilä 31 diesel generator sets offering optimal fuel efficiency.

The Wärtsilä 31 four-stroke, medium-speed diesel engine will meet IMO Tier III regulations. The propulsion system will enable the ship to cruise at a speed of 20k.

Contractors involved in combat support ship project

DSNS signed the first two contracts with RH Marine and Heinen & Hopman for the construction of CSS in March 2020.

Damen placed a contract with Wärtsilä for four diesel engines and a selective catalytic reduction (SCR) unit in June 2020.

Rohde & Schwarz (R&S) was selected to install internal and external communication systems on board the vessel in July 2020.

DSNS contracted Alewijnse Marine for electrical installation works on board the CSS in July 2020. Holland Marine Lifts (HML) will provide ammunition elevator for the supply ship.

GE’s Power Conversion business was contracted by DSNS for an energy management and electric propulsion package for the vessel in September 2020. The contract includes the supply of main switchboards, main electric propulsion system with two 7.9MW shaft lines, and associated power management and remote-control systems.

In September 2020, DSNS signed a contract with Facet Netherlands for the supply of a helicopter refuelling system for the vessel. The system is expected to be delivered in the second half of 2021.

Thales is responsible for delivering high-technology radars for the vessel. DSNS signed two contracts with Newthex for doors and a hatch.

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