I was reminded of a scary incident from my youth and I wanted to tell about it. I was sailing a 505 high performance sailboat from the Palo Alto marina in California in wind in the upper 20s. I was 20 or 21. The Palo Alto Marina was killed by the city so it no longer exists.
The sailing venue at Palo Alto is extremely shallow, with a very soft, muddy bottom. The deepest part is in the middle. When sailing on a flood tide, there's a benefit to going left, where the water is shallowest, to get current relief. Carried too far, this leads to boats running aground, in the nasty, soft green mud. To minimize this, our fleet set a buoy halfway up the weather leg, which we called "E". This kept us away from the worst of the mud.
On the day in question, I was sailing with a different boat than usual. We were getting close to the layline for where E had been 5 minutes ago when we realized it had drifted, and we were a little overstood. So we tacked right away and sailed towards E. As we got closer, E was continuing to drag it's anchor so we bore off to follow, when suddenly we capsized, hard, to weather.
I was in the water, under the sail. An experienced sailor can usually see a capsize coming a few seconds in advance, but this one was a complete surprise. Consequently, I was pretty disoriented. The water in the bay near Palo Alto is pretty murky and visibility was less than 2 feet. I couldn't see the edge of the sail. I hadn't had much time to catch a breath before the sail came down on top of me, so I didn't have much time.
I made my best guess, and fortunately, was not too wrong. I quickly found the edge of the sail and found my way to air. The skipper, who I did not know well, was looking for me and I spoke up as soon as I realized. I said "What the ... happened?"
He explained "The centerboard broke". I immediately understood. 505 centerboards are designed to jibe in their trunk. there's a clever arrangement that if you rake the board slightly forward, it increases its angle of attack. this increases lift and thus pointing angle quite a bit, and also load. But if you're sailing too low, it greatly increases the lateral force on the board. In this case, it sheered off right at the hull. The right thing to have done was to rake the board aft a little when we'd had to bear off. We both knew it but there was so much wind, we didn't want to stop hiking to do it, especially when.
The moment when I realized I was trapped under the sail and didn't know exactly where was what came back to me. A 505 main sail is vaguely triangular about 20x12 feet. when it's on the surface of the water, the sun is illuminating it, but everything else is in shade, and the water was pretty murky, so I couldn't see the edge of the sail or any part of the boat. I literally had to guess. worst case is I might have swum the wrong direction maybe 15 feet or so, before I found an edge, and provided I didn't get further turned around.
I've tried to confine the sailor jargon to the explanation of why it happened--you should be able to figure out what it was that happened without understanding the jargon.
