Shipwreck Rock Rapid
This rapid is named after the house sized undercut boulder that blocks the entire center of the river at the bottom of the rapid. Lines exist around both sides depending on the water level. As a rule of thumb, it is best to finish left of the undercut at levels below 2000 cfs because the right channel begins to close up and the water that doesn't make it through generally drains from right to left across Shipwreck's upstream face. Above 2000 cfs, the right channel opens up enough for rafts to pass through, and it tends to be a safer passage.
At low water there is a guardian rock in front of the giant boulder that diverts a well defined channel of water to the left of the undercut, however at higher flows, water pushes over this with great force directly into the middle of the rock's upstream face. The line still exists to the left at higher water levels, but the move becomes substantially more difficult with an increase in volume and the consequences of error are very serious.
This rapid is located at a left hand bend in the river's course directly below Conestoga Rapid. It can be scouted from both shores and has, depending on the water level, both a right and left entrance. The right is a bit more technical and is only runable in rafts at higher water levels, but it avoids the necessity of crossing the river in front of the undercut through the course of the rapid. The left line is a little wider at the top, but has some hazards of its own. A razorback rock is concealed directly behind an inviting wave just after the entrance. You will want to miss all of this mess to the left where you will hug the shore, weave between some boulders and either make a break for the right side of the river or set up for your move to the left at the bottom.