George- The engine was modified by Henery to power the David No. 1. I do not know if he constructed the transmission from engine to screw (a ring gear driven by the engine that turned a pinion connected to the screw shaft)he is responsible for the engine that powered the boat. The hull of the David was described as "wormeaten" in 1865. She was covered in soft pine, no seasoned Oak being available.
Pvt. James M. Carroll was released from duties at the Charleston Arsenal to assist in the firm of William S. Henery's efforts.
Capt. Lee attempted to have the Henery foundry committed to the David project. Major Chambliss, head of the arsenal, had the attempt twarted in order to maintain control over the subcontractor.
Gen. P.G.T. Beauregard encouraged the David project.