I'm the owner of the website www.chriscraftstingers.com - a site dedicated to the history of the Stingers built by Chris-Craft. The 31' and 39' Stingers were based on Excalibur designs. In my research of the history of the Stingers, I ran across some interesting history regarding a set of Excliburs built to be used as drones by the military. You can read about this history in the May, 2016 newsletter found here: http://chriscraftstingers.com/newsletters.html. I'm always interested in finding out more history regarding the Stingers and the Excaliburs, so feel free to contact me at [email protected]!