Submarine Hole is a slower rapid, and the last major rapid on the Illinois River. The general plan at all flows is a right entrance, and working all the way to the left side. The exit of this rapid is a narrow slot between the bottom left wall and a large rock in the center of the river. During this ferry, watch out for a large hole in the center of the river, which will give you trouble if you end up in the Submarine Hole.
It is somewhat common to flip off the left wall – if you are going to bump into this wall, recommend hitting it with the nose of your boat to avoid this flip. Below this rapid is a big pool, so you’ll have time for cleanup.