Curious

Just to drag this topic back to the original question....

The real reason the propellers are mounted in the rear for ships is that they are overall more efficient that way. While there are maneuverability and yaw stability issues, most ships are designed to go from A to B as efficiently as possible so a rear mounted propeller is the best.

While TimB referred to "open water" efficiencies being higher, modern (i.e. post Lerb's 1953 paper) wake adaptation design renders forward propellers obsolete. The reason for this is the adaptation of manipulation of J (Advance Coefficient) so as to recover energy from the viscous slowed wake behind the hull (the so called Taylor Wake efficiency), which may reach 30% recovery. Additionally, as pointed out by BulBob (Paul), the forward propeller wake causes a pressure increase on the front of the hull leading to increased resistance.

Your original problem with an aft mounted propeller was cause by lack of adequate directional stability, a trait common to canoe hulls designed to be pushed-pulled by a paddle, and easily solved by the addition of a skeg.

 

Bulbob, not exactly..but close

http://www.carbonconcepts.co.uk/product_pages/carbon_concepts_wind_energy.htm