Https://www.cargomaster.com.au/wp-content/uploads/2012/08/img_slider_05-564x350.jpg“It’s called parametric rolling and will transpire when waves don’t strike the bow head-on, but at an angle. The ship goes right into a rolling movement in sync with the waves which, coupled with the ship’s normal pitching mainly because it steams in advance, can displace cargo,” reported Fotis Pagoulatos, http://Conservablogs.com