It's not a joke. It took place on Friday afternoon, during the 4th leg of the Vuelta EspaƱa a Vela (Spain Sailing Tour), from Cartagena to Alicante. While the fleet was approaching Alicante, a submarine suddenly surfaced in front of Endesa-Ceuta. The yacht managed to avoid a head on collision but the extent of damages suffered is not clear. Unfortunately, the photo is fuzzy but the photographer, like the rest of the participants, was caught by surprise. Obviously, nobody was expecting to see a submarine surface in front of them...As a commenter in the original post points out, it's obvious that the submarine didn't just "surface in front of them"... the bridge is rigged, and they've even got their flag up. Those of us who've ever gone in and out of San Diego (and other ports, I'm sure) know that sailboaters will try to get real close to the submarines to take a picture or whatever. Whenever we left port, it was as likely as not that we'd have to sound the danger signal at some idiot sailboater. Once we even hit one -- reported his dumb ass to the Coast Guard too.
Of course, there was the time back in 1992 that the aircraft carrier steamed out of the fog right into the middle of the America's Cup challenger race off San Diego...