I think this is the link. Catana 582 in big winds
However, the Catana is sailing in the South Pacific, not the Southern Ocean. He was sailing between Tahiti and Tonga.
That's a big, pretty heavy catamaran. And 40 knots of wind, I would have expected to see more breaking waves.
40 knots is 8 on the Beaufort Wind Scale, and the description of the wind and seas is as follows: Moderately high waves with breaking crests forming spindrift. Well-marked streaks of foam are blown along wind direction. Considerable airborne spray. I know his instruments plus boat speed sums to 40+ knots, but I just don't think it was quite that strong.
That said, the boat was moving well, and it looked quite comfortable below. Not having any experience with a big cat, I don't know, but a friend of ours sailed a big cat (a one-off of his own design - HUGE compared to that Catana), and I believe he would have confirmed those conditions below. But that is one of the features of the South Pacific compared to the North Atlantic. Big long swells and seas, not the nasty short and violent waves of the Atlantic.
When you're trying to sell big catamarans, of course you're going to show it in the best light. Show me a November/December crossing from the UK to New York in the Catana. I'd be interested in seeing whether it was as comfortable.