Preface: Apologies to the OP for thread drift...
To the relief of many, I am sure, I have no video to offer of the capsize in which I lost my trunks (as the entire forum participants heave a collective sigh of relief). I got my capsizing episodes confused.
That said, I will try to paint a picture, albeit not too graphic.
As mentioned, no video ever existed (at least that I know of!) of the time I lost my trunks. On that day, I was playing hooky from college and, being alone on the lake on a weekday, decided to even out my tan, as it were. I was sailing a little off-brand lateen-rigged boat and had fitted it with a mainsheet cleat because lazy. I had placed my trunks in a little cubby near the mast. The wind gusted, the boat went over, and my trunks ended up in Davy Jones locker. I sailed back to the boat launch unobserved, and used the boat as a shield until I could beach it and run up to my car about 30 yards away. Luckily, no one was around. At least I had had the foresight to hide my keys on one of the wheels of my car and leave my street clothes in the car. Never again, I promised myself!
I once had a video of me capsizing my Hunter 170, but having sold that boat last year, I deleted the folder which may or may not have contained that video. It's nowhere to be found at the moment. Whether this was a subliminally deliberate act I will leave to speculation.
So, on that day I headed out with my GoPro mounted at the mast pointing astern. You see me at the tiller with the marina on one side and a lakeside park on the other. My kicker had stalled out, so I just decided to tack out of the marina. I had not yet unfurled the jib, so I was not pointing well. I cleated off the mainsheet and locked the tiller so I could tilt the motor up. It was at that instant that the wind shifted and gusted. Before I could react, the boat was knocked over with me falling from the windward rail into the lake.
This was not a particularly windy day, but the combination of locked tiller and mainsheet, wind shift, and wind gust conspired to put me in the drink. Having sailed this boat several times in more challenging conditions, I had gotten complacent and did not take the precaution of securing my valuables. My cell phone, boom awning, and other possessions ended up at the bottom of the lake.
The camera now shows a boat on its side with me swimming around the stern to get to the centerboard while the boat starts to turn turtle. Over the course of the next few minutes, the viewer might begin to wonder if I will ever be seen again. What the camera does not show is my struggle to get ahold of the end of the centerboard as it slowly tilts out of reach. I finally realize that I will have to get a grip on it where it exits the bottom of the boat and managed to do so. It takes a minute or so for the boat to start to right itself because, as I realized later, the mast had gotten stuck in the lake bottom. This may have been a saving grace, as otherwise the boat may have turn full turtle. Eventually I was able to get the boat righted, and the camera captures me climbing aboard at the boat's open transom.
It was a bizarre day in general, because when I got the boat righted I decided to continue my sail, and once out on the lake encountered some jet skiers displaying a distress flag with a middle-aged guy draped across one of their craft in obvious distress. I called out, asking what was wrong, and thought I heard one say "My dad died". Maybe he said "My bat died" (battery?). Anyway, everyone looked alive and I told them I would fetch the Coast Guard. It still puzzles me that with two jet skis they were unable, or decided not to, try to get him to shore rather than drift about on the lake.
I made it back to my marina and the folks at the marina office said they would call the fire department, as they keep a boat at the marina and generally handle boaters in distress. I sailed back out and by the time I made it out of the marina (this time without capsizing), I could see that the rescue had taken place and that the apparent victim, looking a bit haggard but grateful, was onboard and headed to a nearby marina.
At this time I already had bought my MacGregor 26S, and was sailing the Hunter for old time's sake. It's likely having gotten used to a larger, more stable boat added to my complacency.
So, the takeaway is: On a small boat, cleating down your mainsheet is a perilous endeavor. Be ready to get wet. Oh, and keep your britches on!