HMS Tracker and her crew have been practising their search and rescue skills alongside the Coastguard and the Royal National Lifeboat Institution (RNLI).
The armed patrol boat linked up with the Belfast Coastguard and several RNLI stations for simulated rescues in the Irish Sea.
The warship and lifeboats searched and located two dummies in the water by using wind and tide calculations.
Meanwhile, the Coastguard helicopter winched the dummies from the boats as they would in a live emergency to transport them to hospital.
Peter Irwin, volunteer lifeboat operations manager for Donaghadee Lifeboat Station, said: "It is the first for a long time we have worked with the Royal Navy.
"If at the end of the day there was a major search going on then every vessel has a requirement to join in a search so it was great to have the professionals of the Navy join us as volunteers and see how we do it on search patterns."
Mr Irwim also said it was "incredible" to see HMS Tracker's crew in action.
"The longer they are in the water, the wider the sector becomes so the search area greatly increases," he said.
He encouraged the public to call the RNLI "very early" in the case of an emergency.
HMS Tracker is based at Faslane in Scotland where it helps provide security, as well as safeguarding shipping in UK waters.