This rapid has an enormous boulder in the center of the channel. Take the left channel and enjoy the wavetrain. The right channel used to be an option, however, in 1999 rockfall closed it off.
The rapid was originally named Boulder Rapid by Robert Brewster Stanton on his expedition in 1890. It was renamed by the USGS expedition in 1923 after they had learned by radio at Soap Creek that President Harding had died. A Cumberson Journey is an excellent journal of the USGS expedition. (32 pages, PDF.) Their radio was also a first for the canyon and is written about in The Waiting List. (19 pages, PDF.)
Other online publications list that the party had learned of President Harding’s death at Lee’s Ferry, however, this is incorrect according to the two sources above.