I got a mast to the head in the surf. I cursed a little. It hurt a lot less than I thought it would
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How hard is it to crack a helmet? I mean is it supposed to crack easily, like a crumple zone?
I've slipped on a gybe and bruised a rib. Couldn't laugh for 6 weeks.
there was a point in my windsurfing where I wore a helmet for a few years, haven't worn one for about 10 or so years now.
I always seemed to hit my head a lot more with the helmet on than I ever have without it, I wonder if others have found the same thing?
I put it down to being a little more careless with that added layer of protection, along with possibly an idea that your muscle memory will try to protect your head, but you don't have the memory to protect the extra size of a head when inside a helmet???
Dunno, just an observation from one person. They are not for me, but do what ever makes you feel good.
I can recommend Nutcase helmets as being pretty sturdy and they do have some cool designs. They have some versions specifically for watersports that may fit the bill. For those of you that have young children, I got one for my 3 year old for riding bikes and skateboards and can't say enough positive stuff about them. The fit and feeling of safety for the little bloke is second to none.
There is one forum member here (up there somewhere) who took an RSX board to the head at full speed whilst in the water during an Olympic regatta. Very lucky to be alive ...
That being said in 10 years I haven't managed to hit my head before, although I've cut, broken, sprained and bruised just about every other part of my body windsurfing.
In the surf I always wear a Gath Visor Model helmet which I have had for over 15 years, as a "hit to the head" is usually obligatory in the surf. I was very grateful I had one on the last time I went out. 
On flat water I usually don't wear a helmet but if it is looking a bit O.T.T. then I wear it.
Managed to hit myself fair across the back of the head with the paddle while SUP surfing last week when I fell of and the wave got me. A lucky escape as I had the helmet on. 
i have a big head
i got whatever fit {barely}
whenever i sail with 7-oh or smaller i wear the helmet
lighter wind usually means less risk for me
when cold it keeps me warm too - no need for gasket head 
