We've broached several times in 20+ years of racing, but the most memorable "knockdown" was this one - and it proved to be a pivotal moment on our then-young son's sailing life.
We were racing a Martin 242 - a high powered lightweight capable of planing into the teens - in upper Howe Sound, a coastal fiord in southern BC blessed with daily breezes into the 20s and flat water.. great conditions. This particular regatta was a windy one, with peaks to 25-30 knots and more-than-usually affected geographical shifts. We had done a couple of laps and had just rounded for the final run. I called for the spinnaker, and was immediately challenged by my wife and her friend.. but the competition was getting away and I overrode them.
Half way through the hoist, we were hit with a strong gust abeam and the boat layed over on her side. It was sudden and unexpected, and as a result we promtply dumped two ladies in the ocean. Our son and his buddy (both about 10 yrs old) had been hanging onto the stern pulpit and fortunately managed to hang on throughout this longish moment.
Aside from the issue of having two people in the water, the boat now lay (fortunately stopped) with about 5 feet of the mast underwater, the boat floating on her beam ends and the keel pointing above horizontal. My buddy grabbed our wives quickly and deposited them back "in" the cockpit by which time I'm sitting on the topsides paint trying to figure out why we're still layed over and haven't 'self righted'.
It soon became clear that the half-raised spinnaker had 'filled' underwater and was preventing the boat for rolling upright. "Blow the halyard" says I, and the boat finally stood up straight (rather rapidly).. at this point, the girls are truly "in" the cockpit, the spinnaker had stuck itself through the shrouds during it's submerged efforts, and when the boat came up the weight of the water in the kite tore off the spreader on that side.
Busily squaring away, dropping the main, and trying to recover the sodden kite,(and keep the rig up) no one on the stellar crew noticed that the guy who had been 'sitting on the topside paint' (me!) was, as a result of the sudden righting, now doing a pretty good imitation of the old "kilroy was here" graffitti, hanging over the side with a death grip on the toe rail.
In the end the errant 'skipper' was recovered as well, the rig secured and we returned to the club without further damage.
As to the pivotal role this played for our son, as a result of my disregarding the ladies' objections to flying the chute they pretty much refused to race with us after that. Our son and his friend (our boat partners' son) replaced the women at 10 years of age and sailed/raced with us throughout their teen years. As many of you may remember, he is a boat owner and avid racer himself now, no doubt at least in part due to that particular episode.....
1984 Fast/Nicholson 345 "FastForward"
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)