I started using Shakespeare trolling motors as far back as 1957 and every one of them were 12V. The very best TM I ever owned was a 6/12V Eagle manufactured by Byrd Industries in Dyersburg TN. It had an unbelievable amount of thrust for it's time. Powered by 2 six volt golf Cart batteries it would run for hours and hours. It also had an unique foot pedal that I loved. The huge flaw in the system was it's fragile motor. The armature had a small shaft that would bend too easily causing the seals to leak shorting out the motor. They were sold to a Japanese company (Tohatsu??) and I haven't seen one in years. It is too bad some American company didn't take the design, fix the motor problem. I would buy one today!