“he noticed a fin next to his windsurfer and he fell into the sea in panic
This is a natural phenomenon, it's happened to me once or twice...
...but, if you read the second article, this story seems a bit dubious...sounds more like he sailed out too far because the wind was blowing but he wasn't so confident at gybing (we've all done that), saw a plastic bag or a bit of wood, fell off trying to gybe, his ancient sail tore, and he couldn't uphaul or waterstart because he's, well, not good enough...and the plastic bag or bit of wood kept "circling" until help came....