Duane,

The Elmira Center for Mark Twain Studies published a small book
about the Pilot's Association (and the later Western Boatman's
Benevolent Association) in its Quarry Farm Volume series:

Edgar M. Branch, _Mark Twain and the Starchy Boys_ (Elmira: Elmira
Center for Mark Twain Studies, 1992).

It can still be ordered from the Center.  See the Quarry Farm Volumes
section at the bottom of its publication list at:

http://www.elmira.edu/academics/MarkTwain/mt_publications.shtml


Jim Zwick