Hi Segev,
i own a F20C and my observation is:
when you sail vertical to the waves which means ahead of the wind and you are quicker than the waves the boat tends to dive in because there is little volume in the front. Normally you can dive in up to the front beam and she will come up without capsizing because she's an extreme wavepiercer hull. That is complete different from some F18 !!! If you are getting nervous while she dives in an pull or push the rudder you will capsize, just depower the gennacker a bit.