Check out this article in Wired mag about the perils of open ocean multihull racing:
http://www.wired.com/wired/archive/14.05/sail.html
Also, there was a huge catamaran a couple years ago called Team Phillips, built in the UK that was supposed to race around the world. Largest ever built, surrounded by all the hype imaginable. 120 feet long, with 135 foot masts "taller than ten double decker buses stacked". Designed by
Christened by the Queen herself. First sail out, bits of it broke. Second time out in the open sea, the whole thing broke up. The crew got rescued luckily, and pieces of the boat were found years later. The guy who started the whole project has a new one, but it's aimed at rowing, not sailing. The French are much better at multihulls than the English were with Team Phillips. They've been building these fast craft for 30 or so years and steadily getting faster and faster.
I saw one of the big ones, Banc Populaire, some years ago, from atop a high headland on the coast of France. There were 100's of boats out on a sunny day, the wind was blowing and this enormous tri ripped through the fleet like a shark through minnows and sailed out of sight.