Thanks all and especially Sam for the extensive explanation.
The background of my question was that I wanted to know what makes one boat more pitchpole resistant than another. I own a nacra 5.8 but would want a 28 foot catamaran. There are a few KL28's on the market (in Europe) but they have category D designation. I trying to find out what would be necessary for cat A/ B. (ISO12217-2,: 2013). One of the parameters would be hull form. Still working on that.