There are also four optional years attached to the deal.
The Dutch group said the vessels are a mix of modern, emergency response and rescue and field-support ships.
Four of these are being built in Asia, with the other being the 1,800-dwt supply ship VOS Provider (built 1999).
"All newbuild ships will be equipped with a revolutionary, wave-piercing bow shape, exclusively designed for Vroon," it said.
Managing
