Check out the topic in GPS-SS called 'Heel hard gevallen'
You will need to read Dutch or use a translator. I used Alta Vista and the translation is not perfect but it seems this poor fellow got very serious injuries and, I gather, temporary paralysis.
From what I can decipher his buoyancy vest saved him from drowning. I good point to remember! And the quick actions of a fellow sailor coming to his aid was also vital.
For all it's fun, we must keep in mind that windsurfing, and especially speed sailing has it's risks. It is wise to keep the risks in perspective and not become blasé about them.
It is good to have a brief discussion with your fellow sailors now and again to reassess the risks in your particular area and in your situations.
For one thing, I always feel a bit more confident to push it a bit if there are other sailors at the fast bit of the course who might be able to come to my aid quickly if the need arose. If the nearest mate is 2kms away I am definitely more reserved.