Please don’t give any more info on this, that was more then enough!

Good comments all, and I agree. I have vertigo when going down feet first, and get off-camber. Try a nasal wash at 20 mph....

I was a lifeguard during summers in college, and used to practice diving - no instruction, form was lousy, but had a lot of fun. All off a 3 meter board Then i finally got the chance to try platforms. I tried the 5 meter first, to try and get the hang of it. It was basically like the 3 meter, but more of a rush - a lot of fun. Then I dove off the 10 meter. Nothing fancy, just a dive. I entered cleanly, and was shocked at how violent the impact was. It was much more than twice the 5 meter... I might try it again, but without instruction, once was enough.

Remember, 32 feet per second per second (9.8 meters per second per second). So you're basically doing 33 mph off a 10 meter platform.

Given the violence of the 10m impact, I wonder what everyone thinks a survivable height is. I don't think I'd want to go much higher without a chute.

The old Navy method was to
Drop feet first toes pointed
Cross legs at the ankle
Cross arms
Grasp opposite shoulders
Tuck chin into chest
Keep elbows tight
DO NOT repeat DO NOT wear life jacket
Grasp a strap to the jacket

You might be able to wear an inflatable style life jacket

Crossing the ankles keeps the impact from spreading the legs and breaking them. This minimizes the the impact on sensitive areas. It also reduces the risk of hydraulic impingement to lower body openings. Yes the entry can cause internal organs.

You want to be as streamlined a package as possible. You want to pierce the water as cleanly as you can. Not land splat. Cannonball dives don't work. At any significant height it is like hitting concrete.

You hold onto the life jacket. Yes when you hit the water you will lose it. But it should be near when you resurface. The jacket is bulky and meant to float. It will stay at the surface. If you are wearing it even or especially with crotch straps it will greatly magnify the impact. It will try to keep you at the surface and remove your head in the process along with other body parts. There will be no give such as a chute opening in skydiving.

Although things may have changed in 30 years since I learned how.

Raspy:
I stand corrected, thank you.

I went through the basic course about 3 years ago, and it's essentially unchanged. I think they've added "Clench buttocks" and "pinch nose" to the routine. But, good advice on avoiding the enema and nasal rinse.

NO LIFE VEST. He's not kidding - remember, they're designed to keep you afloat, with your head out of the water. Often with a substantial neck portion. Guess what part likes to break around that collar?

I don't know the right way, but a former acquaintance jumped off this bridge into the water, 100' below. Somehow he lived, but he had bruises all over his body. As I recall, he said that he did cross his arms and legs, and did wear shoes. I didn't think to ask him if he got an enema from it.
http://en.wikipedia.org/wiki/Pennybacker_Bridge

He was prompted to jump after learning that someone died jumping from it.

We have now had a couple of deaths in the UK from kids and a new craze.

Google TOMBSTONING

Also have a look at

Tombstone Safety

Terminal Velocity when in a maximum drag position (spread eagle) is roughly 124mph. If you are upright, it increases to about 200mph. It takes roughly 5.7 seconds of falling to reach 124 mph, during which you fall about 530 ft.

FYI, acceleration due to gravity (9.81m/s) is considerably faster than a Ferrari.

My math may be off, so feel free to correct me.

"...My math may be off, so feel free to correct me..."

Sounds close enough to me. Doing math gives me a headache...

Hi Glock-A-Roo

http://www.youtube.com/watch?v=xkjDyF1Oss4

I guess we'll just have to ask these kids from Arbroath.