NAVY ships from Portsmouth joined a flotilla of 49 warships for an exercise.
Portsmouth-based frigate HMS Iron Duke and minehunter HMS Quorn are taking part in largest Nato maritime exercise of the year.
The two ships are also joined by HMS Ocean in Baltops 15.
It is designed to test the communication and navigational expertise of the crews.
HMS Ocean’s specialist navigation officer Lieutenant Commander George Storton, 32, of Bosham, said: ‘We had 49 ships taking part of all sizes and speeds and that meant a lot of evenings on the internet researching the vessels, looking at where they could sit in the running order and then sketching out different formations over and over again.
‘This was a massive communications piece as we had ships from several nations coming together on day one of the exercise.
‘Many of us had never worked, or even spoken, before so we had to prepare for every eventuality. Fortunately the whole serial ran smoothly.’
Ships from 17 nations took part in the serial.