But don't worry, they are just pretending!
Boaters on the Solent might be in for a big surprise this week as two Royal Navy warships take part in a large-scale military exercise.
The operation will run from Monday 25 to Thursday 28 October in the Eastern Solent and to the east and south of the Isle of Wight.
In addition to the warships, helicopters, landing craft, two frigates and a patrol boat will play their part in the activity, which will involve the firing of blank ammunition and numerous high-speed craft.
Portsmouth’s Harbour Master is reminding boaters to observe a minimum 50 metre distance of any warship at anchor and to take extra care when approaching the area.
Contact the Harbour Master on VHF Ch 11 or by telephoning 02392 723689 for the latest information.