I met with Dick Tuschick (the owner of Rhumbline Yachts) aboard his PDQ cat a few weeks ago in Boston. He told me that his only gripe with cats after cruising 250k thousand miles (not a typo!!) was in a big head sea. Cats don't like a big head sea and hitting them straight on. He said a big beam sea is no problem at all.
I loved his boat and I've added a small cat (less than 40') to my list of potential next boats. But as others have said, I'm also worried about berthing a cat.
2005 Silverton 35 Motoryacht