not about rocky channel but about marking channels in the backcountry
in general: (& shoaling can be a problem)

http://last-stand.org/HTML/articles/..._kwc_nov07.htm

Wayne.B wrote:
Is anyone familiar with "Rocky Channel" going north from the
Marathon/Bahia Honda area? It looks like it has deeper water than
Big
Spanish Channel which is a little further west. Rocky Channel
appears
to have no navigational aids however which means that you would need
to rely strictly on the accuracy of the charts and/or eyeball
navigation.

Does anyone ever go through there, and if so, is it OK for 5 1/2 feet
of draft? If the chart can be believed, it looks like you could
carry
7 feet all the way up to the gulf. Are there any coral heads or
shoaling to worry about?