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.