The Tunnel

You have now entered the 'Meat' of the run, which ends after S-Turn. The Tunnel is fast, choppy, and you want to be pointing straight! Stay upright through the reflection waves in there, as it's pretty shallow. It gets a bit dark, and it slopes downhill, so you'll be accelerating all the way. When you emerge the tunnel, you face a steep water slide, shoving you inexorably into a huge wall of water/hole at the bottom. Don't be so far left that you fall off the side of the slide, and too far right will put you right into the face of a large boulder. This is one of the funnest rapids, but hold on tight! The hole can get retentive at higher flows (over 1000), and this can be portaged. Most of the flow usually pushes into a large wood pile at the bottom, this is not a place for swimming. 

This viaduct was built ca. 1890 to support a railroad bridge. The Tunnel is 512 feet long, 20 feet high and 40 feet wide; it takes a bend to the left about 1/3rd of the way through, so there's no straight path for light at the entrance.