The ferry from Picton across the Cook Strait takes about three hours. That's ample time, on a day as fine as the one we had, to stroll the multiple open decks, do some reading or snoozing, and in general contemplate what it must've been like back in the day (as they say) when ships were made of wood, food was rations instead of a la carte buffet bars, and the distance to the next island/continent, if there was one, was completely unknown. Staring at the shadow of land in the distance, with nothing but ocean in the other direction will put these kinds of thoughts in your head.