Here's an interesting story by a ship captain on experiencing parametric rolling

http://kennebeccaptain.blogspot.com/2010/01/parametric-rolling-of-car-carrier-in.html

Check this video of the cruise ship Voyager doing some serious rolling.
same site People flying around like bowling pins.

http://www.itk.ntnu.no/ansatte/Holden_Christian/prof/files/inside.mp4


Soooo, the moral of the story is......


It is important for masters to know and understand the
mechanism of parametric rolling. This is because when
conditions for parametric rolling exist the worst possible action
to take is to put the ship’s head to sea and reduce speed. In
normal circumstances putting the ship’s head to sea and
reducing speed is the textbook response to navigation in bad
weather, but in conditions of parametric rolling it will only make
the rolling worse. Conditions for parametric rolling can be said
to exist when the wave length is approximately equal to the
ship’s length and the wave period of encounter is half the ship’s
rolling period. The period of encounter will depend on speed. (p.6)

http://www.standard-club.com/docs/MM_Nov02_disc.pdf