Maybe the horse riding inflation jackets

southern stars sadlery sells them. Only problem is how to trigger it for the emergency and not everytime you fall off or gybe. Dont sail ovrr finned. Thats about the only time i get chucked off. Also be carefull after sailing deep and then rounding up, you need to decelerate first otherwise the apparent wind swings forward too much and there is a heap of drag on the tip of the rig and that lifts the front of the board up. multiple times with same injurry suggests you need to think carefully about what is happening and perhaps change style or behaviour or equipment or sports. Try not to hit the rig which means clean separation or solid bracing. Also beware of over doing it unfit or untrained on modern gear. I had no injuries or big offs last season other than a broken toe from jamming it in the footstrap, after 15 years off but a gradual comeback and moderate fitness. This year i had a fitness sapping illness and i think i got back into it too quick, one bad off and into the boom fortunstely just bruised shoulder, then i ruptured a big toe tendon gybing and sailed a few times before i knew how bad it was, and i had a lot of big offs at the end of runs due mainly i think due to lack of foot control. So when the toe is good i plan to ease into it slowly and get the fitness and skills back gradually. good luck with neck but seriously think about what is going on and why. Eliminating the risk is always better than ppe (personal protective equipment)