What about a cofferdam?

greenspun.com : LUSENET : Junkyard Wars : One Thread

I think it would be interesting to build a cofferdam. You have a reasonably shallow pond (6' would be good) and a float indicating the location for a box on the pond bottom. The box has a simple trigger that will open when the water recedes around the box. The contestants must create a structure that can be floated into place, made to sink to the bottom, seal on the bottom (mud probably) as well as possible, and pump out the water. When the water drops around the box, something like a balloon pops up.

Whatever they build has to float, propel itself (maybe with the same pump), drop a sleeve or something that will resist the water to the bottom, and pump out the water as fast as possible, knowing the bottom probably leaks a bit. Do you lower a tube from a boat or do you sink the entire structure down to sit on the bottom? Lots of interesting possibilities here.

-- Charles Owen (cbowen@cse.msu.edu), January 29, 2001


Really neat idea. Now how do we come up with the two systems that JYW uses. But i can see quite a bit of excitement here.

-- Stephen A. Binion (Stephenbinion@hotmail.com), January 29, 2001.

Could they use compressed air to displace the water like in a caisson? That would be a different way to do it. Another problem is trying to keep it on the bottom. Once they remove the water, it will want to pop up like a cork. If they used two 55 gal. drums welded on top of each other to make the coffer, it would take over 800 lbs of ballast to keep them under water. Makes it harder to float out to the site. I like this challenge. Can't wait to see the show!

-- Mark Richter (mark@troyjaycees.org), January 30, 2001.

Really does my heart good to know there are a few original ideas floating around out there. Hats off.

-- ChanzReed (uncleniblz@aol.com), January 31, 2001.

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