Horse Mesa Dam

Three 20-foot flatbed trucks loaded with equipment were driven to the site over a twisting one-lane dirt road with a sheer drop-off hundreds of feet down. The dive station was then erected on a floating emergency-use helicopter landing pad tied to the dam. The crews were housed at a resort that was a 20-minute skiff ride away.

Fifteen separate dives were necessary to remove the old rail pains, drill new holes in the concrete (complicated when the drills hit embedded rebar), and insert new pins. Working at the depth of minus-260, each diver had only 40 minutes to work from the time he left the platform until the time he left the bottom of the dam to return to the surface. Because divers faced 90 minutes of in-water decompression followed by an additional 3 hours in the decompression chamber, three dives per day were the most that could be done.