"tom" wrote
I was recently on a 21 footer with my son-in-law at the till cruising
along fairly well with 25-30 knot winds when he noticed we were
heading into an area of additional wind. While alerting me, he
disengaged the mainsheet and when we rolled he let it fly. The roll
took us over nearly 90 degrees and we shipped water over the coaming 6
to 10 inches in depth.

I used to sail rental boats that size on a bay surrounded by many tall
buildings just inland of the ocean. Often, I'd be on a tight tack when I'd
pass gap between buildings and get knocked down to the point of having water
over the coaming and in the belly of the sail. With little assist from the
tiller, the boat itself would head up into the wind, right itself, and sit
there luffing the water out of its sails. Scared the crap out of me the
first time but it became commonplace until I learned to read the wind from
ripples on the water. Naturally YMMV.