FEATURE | Dutch patrol ship to undergo hydrofoil spoiler refit

The Dutch Defence Materiel Organisation has recently confirmed an order for a new underwater hydrofoil spoiler to be installed on the Royal Netherlands Navy’s 108-metre ocean-going patrol vessel HNLMS Zeeland.

The device, which will be supplied by local company Hull Vane, will work by converting energy from the stern wave and the ship motions into forward thrust.

The foil will have a span of 11 meters and a chord length of two, making it one of the largest hydrofoil spoilers ever built.

The selection of the Hull Vane spoiler came after the design was tested extensively at a model basin at the Maritime Research Institute Netherlands (MARIN).

No drastic modifications to existing ship layout

The main benefit is the reduction in fuel consumption, expected to be at least 10 per cent. The top speed will increase and the modification will reduce the stern wave, reducing its visibility from aircraft and satellites.

As the spoiler dampens the ship motions in waves, Zeeland‘s helicopter deck will move less, making it easier for helicopters to land in rough weather. The same applies for the slipway in the stern: as it moves less up and down, the launch and recovery of Zeeland‘s small interceptor boat will be easier.

Model tests have also indicated a significant reduction in bow slamming, leading to improved comfort on board.

The only difficulty encountered in the project was in ensuring the spoiler and the stern slipway for launching and recovering Zeeland‘s interceptor boat would not interfere with each other’s operations. The solution agreed upon was the adjustment of the bottom hull at the stern to ensure proper installation of the spoiler lest it be struck by the ship’s propellers.

Future prospects

Hull Vane expects the spoiler would have a service life of at least 18 years, thus ensuring minimal downtimes for maintenance.

Zeeland is expected to enter drydocking for major maintenance no later than 2022. The stern bottom hull will also be lowered further to enable installation of the spoiler.

Dutch navy officials said that, depending on Zeeland‘s performance following the incorporation of the Hull Vane spoiler, similar installations may also be carried out on other active ships in the fleet.

More great content as part of this month’s Hydrofoil Week right here.