Aberdeen owner Sentinel Marine is spending £36m ($46m) on three new emergency response and rescue vessels (ERRVS).
An unnamed Chinese yard is building the trio, named Cromarty Sentinel, Trafalgar Sentinel and Viking Sentinel.
The move creates 80 jobs for the owner.
The vessels will be delivered by the end of 2020.
Rory Deans, chief executive of Sentinel Marine, said: “This is a speculative investment by Sentinel Marine, based on the significant demand there has been for our fleet of high-specification custom-build vessels which we have introduced on a rolling programme since 2015.
“There has been an increase in activity in the North Sea over the past 12 months, and there is certainly a market for vessels of this standard. The multi-role nature of the ships, together with the technology on board, age and efficiency, offer an attractive proposition to operators and have been very well received.”
The company took delivery of the last of a series of nine ERRVs last April.
They were also built by Chinese yards.
