A force-ten storm. As the prow of the RSS Ernest Shackleton is built for pushing its way through ice, it means that it is far less stable in the open sea. The boat goes through all sorts of strange motions as paintings hang off the walls at an angle of 30 degrees. It’s strange the way everything is the same, but gravity just works in new directions. Plants become like triffids – spontaneously groping in one direction and then another. Towels hung over clothes-rails wave out one leg like ballet teachers. I was filming one of the paintings when an unexpected lunge, sent five people on armchairs flying past me, to end up on the far side of the bar in a tangled heap of beer and legs. Every now and then there’s a huge judder as the ship hits the bottom of a trough. The portholes all turn white and the ship ploughs through the body of the water, until it climbs again and rolls over the next crest. But with amazing luck, I seem to be immune to the seasickness that plagues my bunk-mates.