Diving Challenge questions

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Congrats to Art attack! I had to go to bed after the first hour, but will watch hovercraft later...

A couple questions:

1. Was the shark really in the tank? They had one shot looking down as a ray went between the camera and the divers, but the shark and divers were never shown together! The tank didn't look big enough for a Shark, but it may have had more volume that the display area.

2. They never showed the source of the faceplate for the Young Guns' helmet. They must have had to cut it?

3. How much distortion was there in the water jug? That was the concern of the Young Guns' expert, yet they created their own set of problems with their advanced solution!


Once again it seems that simplicity won over the elegant solution. I was amazed to see both pumps working so well. Just as well the Rusty's weren't manning the piston pump!

This challenge seemed to be one of the shortest builds I've seen. Both teams seemed to have time for fun and silliness! Quote to remember (as Ken and Flatmo were "playing" the bolts/plates/tools), "You guys are having way too much fun!"

-- Michael (Canadian P.Eng.) (michael@mks-tech.com), January 18, 2001


That aquarium was way bigger than just that viewing area. It was breathtaking to say the least. There was a huge clear tube under the water which you could walk clear around and view everything from underneath. That tank had 8 sharks in it I believe. One actually grazed George's forehead to say hi. I think for once, George was actually speechless. They did feed the sharks before anyone got in. Also the sharks mostly stayed just out of range from the shoot once all the people got in there. There were probably 10 people in that tank doing filming and safety things./ I don't know about the glass circle used for the Young Guns lens. It might have come from that big orange self- righting life boat we all see in the yard. As far as having fun. We always find time to have fun. We play junk in our shop sometimes when someone hears someone pounding in a rhythmic fashion....others join in and our whole shop turns into a wonderful percussion session. Thanks for the email!

-- Duane Flatmo (flatmo@humboldt1.com), January 18, 2001.

The underwater view through the water jug was sort of like a panoramic picture, expanded in width, but not in height. It only took a moment to get used to objects underwater appearing to be a bit further away than they actually were. One odd thing that did happen after I took the helmet off on the surface, I was a bit cross-eyed for a few moments as my vision readjusted from compensating for the underwater curvature distortion.

The Young Guns used a scrap piece of thick, clear plastic for their faceplate. It was cut to shape with a saw and glued into the ring formed by the belled end of the milk can they found.

Editing the best (and worst) moments of each challenge can't be easy as so much happens while we are working, but I'm glad that it was apparent how much fun we did have.

-- Greg Bryant (greg.bryant@disney.com), January 18, 2001.

I was afraid the ambient water pressure would crush or at least bend the water bottle. How much deeper could you have gone without that happening?

Also, both teams needed one-way air valves for their pumps but we never saw where they came from or exactly how and where they were installed?

I also don't see how you were able to seal those tires. Were they only sealed on the downstroke?

Thanks, Good job.

-- El Kid (sizzl@mindspring.com), January 20, 2001.

Those valves were in a box of pump parts and valves and stuff. It's amazing how many tons of parts are out in that yard...... I cut a hole in the top of the pump top plate, then welded in a 2' long piece of threaded pipe at an angle to screw the valve and our hose onto. I'm not sure how far that bottle could have gone down underwater before collapsing. I bet Greg could get his calculator and figure it out, he's good at that.

-- Duane flatmo, art attack (flatmo@humboldt1.com), January 20, 2001.

re: collapse of the water jug due to pressure.

Not an issue. The air pressure on the inside will equal the water pressure on the outside. The main function of the helmet is to hold a bubble of air at the bottom. The only stress on the helmet will be the rising force of the air vs. the weights used to keep it down!

-- Michael (Canadian P. Eng.) (michael@mks-tech.com), January 20, 2001.

Right, Michael. It would have been a different matter if the helmet had an air-tight seal around the diver's neck. But since it was open at the bottom, if the air pressure didn't exactly match the water on the outside, it would either spill over (if too much), or compress until the pressure equalized (if not enough). When it compresses, the water level just rises a little to take up the extra space.

-- Eric (earsjohnson@usa.net), January 23, 2001.

The depth was 20 feet, right? I think I read somewhere (I might not remember correctly) that every 30 feet of water depth raises pressure by 1 atmosphere.

Assuming that each expert was 6 feet tall, that means they are submerged by about 15 ft.. That makes the equalizing pressure 1.5 atmospheres to keep water out of the mask. Pumping enough air by hand to equalize that pressure actually looks like quite a feat-- For the majority of the experts' durations under water it looked like their helmets were in danger of being flooded! =) (the placement of the airhoses weren't optimal as well so they explained..)


-- Thomas (trh1@cris.com), January 23, 2001.

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