When you are knocked off the boat but still attached to it, the boat does not necessarily stop, and it is possible to be dragged. Here is what happened to Rick in a rather bizarre situation:

He and crew were racing our Hobie 18 in a regatta at Put-in-Bay on Lake Erie. Rick should not have been racing at all, because he was recovering from broken ribs at the time.

As they came into the finish line of one race, he was on the trapeze and he somehow managed to, with his body, hit the swim platform of the committee boat. This resulted in a couple more broken ribs (other side), and it also knocked him off the boat. Still attached to his trapeze wire, he was flipped upside down and was being dragged upside down in the water behind the boat and between the hulls, as the boat headed down the line on a reach, slowed by the "sea anchor," but not stopped.

Thoughts of imminent drowning were going through his mind, because he was not able to get himself right side up. Fortunately, he was close enough to one of the rudders to physically turn it so that the boat would head up into the wind and stop dragging him. Once the boat stopped, he was able to right himself, and his crew helped him back onto the boat.

Because everything happened so fast, his crew did not know what to do to help and did not immediately react by heading the boat up into the wind. Rick was underwater for approximately a minute.

We cannot possibly dream up every conceivable bad thing that could happen on a sailboat and some of the real-life things that happen are things we would never dream of.

(By the way, he is not in the habit of crashing his body into committee boats, but because of his still painful broken ribs from a former injury, he was having to cleat the mainsheet, and apparently it came uncleated at the wrong moment, just as they were finishing. And the fact that it uncleated also allowed the boat to fall off onto a reach.)