I measured the circumference of my head above the nose, without a helmet and with 3 brands kitehelmet: 59 cm, 64, 68 and 70.
If the water replacement on impact is calculated as a half sphere, it is 1,7 liters, 2.2, 2.6 and 2.9.
Water replacement? I'm guessing you're talking about the displaced volume of the helmet. I don't think displaced volume factors into it at all. Surface area does make a difference (belly flop vs. a dive), but the difference in surface area is pretty small.
PLEASE DO THE MEASUREMENTS. IT MAKES A BIG DIFFERENCE, AND THE GATH WAS THE BIGGEST I MEASURED.
So the average of these 3 helmets means a 50 % increase in force on the neck.
Maybe this increase is lessened by a time delay.
The helmet is designed to absorb the energy so that your neck doesn't. If there is a small increase in surface area, the helmet absorbing the energy more than makes up for this.
IF A HELMET WAS DESIGNED JUST TO ABSORB, IT WOULD BE A PILLOW. THE HARD SURFACE IS THE BIGGEST, WHICH CAUSES A HUGE INCREASE OF POWER OF IMPACT.
I WOULD BE GRATEFUL FOR ANY SCIENCE DONE ON THIS, BECAUSE I'M NOT GOING TO RISK MY NECK ON JUST YOUR STATING THAT THE ABSORBING MAKES UP FOR THE INCREASE.
But after this calculating and reckoning that 99,5 % of my crashes are on water, I don't think I'll do it again soon.
Unless RickI and others keep being so persuasive (you really are!).
So for every 200 times you crash, only 1 time is into something hard, so the don't wear a helmet? I don't think that one makes too much sense.
IT MAKES SENSE TO ME BECAUSE I DON'T WANT THAT INCREASE OF IMPACT IN THE 200 TIMES I THAT I DO CRASH ON THE WATER
ACTUALLY I'VE NEVER CRASHED MY HEAD INTO SOMETHING HARD WHILE HAVING MY LOT OF BEACH CRASHES, BEING TOWED 4 TIMES IN MY FIRST YEARS OF KITING, LONG TIME AGO.
BUT I KEEP CRASHING ON THE WATER.
SO THE RATIO IS CLOSER TO 1000:0
I taught kiteboarding to a traumatologist and his son. He works at emergencies in the hospital.
I gave him the choice to wear a helmet during lesson, and he declined.
One doctor thinks you shouldn't wear a helmet after you told him your flawed theory on increased displaced volume? I'd have to guess most doctors recommend helmets.
The topic of this thread is "doctors on helmets".
and his son against using helmets.
As we don't have many kiting doctors in this thread, this should be a legitimate contribution.
His decision speaks more to me than your guessing that most doctors might recommend helmets
of kiteboarding conditions or research.
i'm not against helmets - i have plenty of them.
i'm for knowledgeable decisions, so i hope there will be research.