Paddling the Jackson Kayak Big Tuna through 20 Rock Rapid (Chattahoochee River.) Known by many as “20 Rock”, because of the large rock outcropping that the rapid flows through and it’s location to Highway 20 (Cumming Highway). This rapid is roughly 200 yards north of HWY 20 on the Chattahoochee River. 20 Rock is about a class 2 rapid (when the water is NOT being released from the Buford Dam. So for experienced whitewater paddlers it’s barely a speed bump. But for most folks that paddle the Hooch, this rapid can be a bit intimidating. This rapid claims a TON of gear from those that flip over in the turbulent flow: boats, fishing gear, coolers… etc. Many years ago, this rock was known a Drowning Rock. This is because people would get trapped on the main rock when water was released from the dam… as the water rises, the light flow on the east side of the rock becomes heavy… stranding anyone still left on the highest point of the rock. Many people have lost their lives here over the years. Always wear a PFD and check the water release times before setting out on the Hooch. The Big Tuna is the Best Kayak for me because it is very stable. This feature makes it a great River or Ocean Kayak.