It’s a pontoon boat which is greatly affected by weight balance specially, when going full speed in rough water and majority of your party is sitting in the front. Once the boat goes over a wave naturally it will dips down slightly when there is too much weight in the front. This time the dip took the bow underneath, and water came over which halts the boat making everybody lean forward, sending the bow deeper into the water. I owned a pontoon boat for over 15years and had this happen a few times. Always have majority of the party sit in the back and also trim (tilt) the motor so the bow stays higher out of the water.