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I'm wondering if anyone knows the distance from the roaddeck to the bottom of the steel at the center of the NRG bridge and at BD launch point if that isn't dead center.

I know at least 2 seconds worth. That's when I hit it and there was still some more to go.

Here's the video. (RealPlayer)

 

My memory says 120 feet...but I do things that effect my memory so ................

Do anyone know if two seconds means that it is 60-70 feet?

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Kris.

The BD launch point isn't over the top of the steel arch, it's over the center of the river, where the steel goes down a little further.

So if the BD launch point is to the left of the center of the arch (hypothetical), if you took 2 seconds and had a 120 left would you have to worry about the steel? If it's to the right of the center use the same question but switch the left's for right's.

Also, is the 2 seconds recommendation, open at 2 seconds and you will avoid steel, or deploy at 2 seconds and you will avoid steel.

Open at 2 seconds makes me think the steel is only 60-70 feet down, deploy at 2 seconds might be more.

Just so everyone knows why I'm inquiring (in case this seems like a stupid topic), I'm wondering if a slider up PCA off of the bridge is practical. Knowing that offheadings are an issue of slow slider up deployment, the steel is obviously a consideration.

First of all, there is a substantial amount of steel below the bridge. I'll try to find out exactly how much, but you cannot accurately correlate the height of the steel based on freefall delays.

Other factors:
-Our ramp system is about 9' above the road deck.
-Rappelling ropes are approximately 150' to your right on opening. Slider up PCA openings aren't as reliable as slider down PCA's.
-Exit point is approximately 50-60' off of bridge center.
-I have seen PCA's hit both the NRGB and the Jolly Green bridge.
-I have seen people hit the NRGB in freefall.

I know what you're searching for. I think a better approach would be PCA's from the catwalk or lower. We are researching this as well.

The speed at 1 second is clearly wrong. The acceleration due to gravity is ~20mph per second until wind resistance plays a factor, particularly around 4 seconds. At 1 second, a jumper is going ~20mph. At 2 seconds, ~37-40mph.