In his book, Electric Boats and Ships: A History, author Kevin Desmond wrote briefly about the journey that led Duffy Jr. to designing the Power Rudder.
"Duffy wanted to perfect his idea of a rotating power drive, knowing this was the best way to push a small boat, allowing much more room to the interior, easier installation, superior maneuverability, quite operating, and less servicing.
Duffy Jr., along with Alex Kozloff and Charlie Sparkle, built and refined the drive unit for three years, The rudder had in it a spiral bevel gear that drove a prop shaft out the rear of the rudder, and the drive shaft went up inside the boat where the motor was coupled to it. All of this turned and gave the drive great maneuverability. (NOTE: It also prompted Duffy to switch to a pancake design motor which was smaller, lighter and put out more horsepower.)
The Power Rudder revolution was an expensive, time-consuming adventure for Duffy because to use the Power Rudder each boat in the Duffy line had to be redesigned from the hull up. It took four years to finally finish new molds for every size boat Duffy offers, the task being completed in 2008."*
