This section is from the book "The Boy Mechanic Vol. 2 1000 Things for Boys to Do", by Popular Mechanics Co.. Also available from Amazon: The Boy Mechanic, Vol2: 1000 Things for Boys to Do.
The rear fork of an old bicycle frame, with the crank hanger attached, and the rear hub constitute the main parts of the propelling device. One of the cranks is cut from the hanger and a bracket attached to the frame, as shown, for making it fast to the stern of the boat. Two propeller blades are bolted to the rear hub. A rudder is fastened to the rear tube of the frame with hooks and eyes so that it can be turned with a handle at the top, or with ropes run to a wheel. The illustration shows the connection of the device to a boat. - Contributed by Berge Lion, Fresno, Cal.
Ill: The Rear Fork of a Bicycle with Its P. Rts Constitutes the Main Propeller Attachment