Airboat Notes

From instructions:

ENGINE: The Volkswagen "Beetle", air-cooled automotive engines vary from 1200 to 1600 cc displacement and develops 40 to 60 hp. Any of these models can be used, either the vertical or pancake versions. ...
PROPELLER: To couple to the engine use a modified crankshaft pulley, machined to suit the prop hub. The existing pulley is removed and replaced with one commercially available the incorporates the sheave for driving the belt and also adapts the prop to the hub. With the hub dimension known, and the pulley from the engine, a good machine shop could also make one. A two blade prop will vary in diameter from 45" to 50" depending on the engine and pitch. A three blade prop is quieter and has less vibration, with a usual diameter of 44". Props do have varying qualities and the size required should be varified by the manufacturer.

Further notes on the engine

The VW Beetle wieghs approximately 220 lbs (100 kg).
Several builders have asked if other motors can be used... The mount is designed for the VW motor and would have to be modified to suit other motors. We would not advise any dramatic increases in weight as this could affect stability. We do not have details for other motors that could be used on the Airboat and can only say that alternative motors should be in the same weight range. All of our testing and calculations used the VW motor in the weight and hp ranges stated above.

See Useful information/Boatbuilder Links for a list of prop suppliers.

VW Transaxle Cutting