The SwimBug needs a propulsion system to drive it through the water.The Swimbug will use the latest in technology with electric pod motors driving the craft through the water.
The propeller will be a commercial unit as used in water ski impellers.
The electric motor will probably go through a reduction gear of 4:1 to reduce the power requirement to move the propeller.
1000 RPM on the motor will have 250 RPM on the propeller, giving the motor four times the power effort required to move the propeller in water.
Check it out
The funding page is now complete http://www.crowdfunder.co.uk/amphibious-water-road-vehicle
Take a look and any comments "In my book " appreciated.