Can a Direct Link Between Car Engine and Jet Pump Power an Amphibious Vehicle?

[Joiner]

Well if you do intend to chop the top off so you can use welded doors and drop some weight, and still want to drive this vehicle on the road, I must insist a roll cage be installed. Removing the roof lowers the structural integrity of the safety bubble designed into unibodies.

 

[Qublai]

Modern alternators/generators as used in hybrid cars are much smaller and lighter than they were in the past. The problem with these are not size or weight but complexity and cost.

The clutch off an AC compressor can not handle anywhere near the power you will need. You may want to consider a simple mechanical dog clutch. This is the common way forward and reverse are engaged in boats.

 

[jack action]

Going back to basics, instead of connecting your engine crankshaft to an hydraulic pump or generator, you could link it directly to the jet pump.

All you need is a mechanism to lower the jet pump when you're in water, some sort of clutch to engage it, put the car in neutral and you're in for a great boat ride! I don't think that the fact that the jet pump is under the boat instead of being behind it will make that much of a difference on thrust power. Worst case scenario, you could have two of them coming out on each side.