Here are some interesting results from investigating causes of low frame rates, which you can try:
In the mission editor, load the Atlantic environment and place a player cutter.
Fill in the Mission Properties panel with your forum name and Cutter selected as the player ship.
In the Ocean Settings, set all wave heights to zero.
Save the mission—DO NOT UPLOAD—and run it.
In external view from astern, zoomed out, I got 15 FPS.
Switching to helm camera and zooming in on a blank overhead, I got 23 FPS. (There is a minimum amount of rendering to do)
Back to camera #1 and 15 FPS, I turned off the overlay controls with the C key. This gave me 27 FPS.
Turning off everything including chart and conning circle with the Tab key gave me 30 FPS.
If you try this in free roam instead of struggling with the editor, you will get much lower frame rates because of the AI, even if you set the wind velocity to zero. “Wind†in free roam is really a wave height control; it is not the same as the wind setting in the editor’s Weather Sim.
Just for fun, I set Cutter’s visibility to false, leaving only the RIB and smoke—and the bow wave if you advance the throttles. In helm view, you can also see controls and indicators to give you an idea how much it costs to display that stuff.
Incidentally, this also explains the ghostly lights-with-no-ship seen in campaign missions: The visibility of the ship was false, but that does not hide stuff attached to it in the ME or ship editor. Remember that when you want to hide a ship in a mission.