BLUEMOMENT

What happens to the radar picture when the angle of transmission and reception are changing so rapidly and at such an angle. At some points the angle must be into the water at 15degrees, and others perhaps 20-25 deg above horizon.
Does that make for difficult radar reception?

The beam is a fan shaped (vertical) narrow plane (as you already knew) and the returning pulse of any target would be home before the boat had actually moved much in real terms. Also, I bet you get some form of image stabilisation software as well in these posh new-fangled boxes.

If you look at the YouTube page meticulous inspection reveals the video came from Arena Aviation.
Who?
Don't know, but not 177 or the Coastguard.
Pretty impressive shooting and flying, though. How they circled the lifeboat with the camera on-subject I can't fathom, unless the chopper flew backwards into the gale for a time. Pod slung underneath?
The ferries were running throughout the period although they had to use the inner linkspan for a time. I was working on the boat just over the fence from the Ardrossan terminal. There were signs at the terminal building (handy for a coffee for me) detailing roads inaccessible on Arran and bus servicves not running.

http://www.arena-aviation.com/?

Donald