Ive taken a truck Holyhead - Dublin or Cairnryan - Larne probably a hundred times. Winter storms can certainly liven up what is otherwise a dull interlude although standing on the dock watching a ferry struggling to dock can be worrying.
The irish cat (Jonathon Swift IIRC) has earnt he nickname the Olympic Flame, as in the winter it does not go out very often. I believe the the Stena cat is now an office block in Turkey as its Omega-esque thirst made it unviable.
As I understand it the amount of chaining down has various stages dependant on what the weather forecast is, with the most common variant being 'block' chaining where only the trucks on the perimeter of a block get lashed and those in the middle are free to rattle around if Neptune kicks off. What I've never fully understood is this. It's all very well lashing down before departure, but after an hour of rocking from side to side the suspension will lose a lot of air and might of dropped three inches. Do they go round tightening the chains or let them go slack?
Turners nearly lost a tanker out the back of a ferry on the Cairnryan crossing a few years back. Seems the muppet didnt put the brake on and it was 'lashed' to a continuous rail alongside. As they cleared port the captain opened the taps and back she rolled. Took out the loading door and the only thing keeping it out of the sea was the cab wedging against the roof.
Steve