It's a tradition, they do it every year at the masters, but usually in a practise round or such. This video is Martin Kaymer in 2012, in 2009 Vijay Singh also did the same. Video below:
Very cool video, thanks Ike! It looks similar to the SS Thistlegorm which I dived in the Red Sea 3 weeks back. It was also a WW2 military cargo ship that was sunk by ze Germans with all its cargo onboard incl tanks/trains/bikes/ammo etc.
I still need to compile my videos, but I will upload a few pics of it in my UW photo thread.