Circular saw boat motor. Need help and suggestions.

I am building a small, plywood boat and looking to power it. I have built many projects made out of wood but never anything mechanical. I am looking for advise from people who have done something similar. In the image I attached there are three problems I face. 

1 and 2) To transfer motion from the circular saw to the prop's axial I was thinking using something similar to a bike chain. What parts would you use to do this?

3) How would you secure a prop onto an axial?

I am not looking for this to be a fast or anything. Just more of a practice project. 


Picture of Circular saw boat motor. Need help and suggestions.
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Toga_Dan5 years ago
Anything above 50 volts is considered hazardous voltage. Take care not to complete a circuit with your heart when somethin gets wet.
I love that your thinking outside the box on the engine but I'm not sure this would be a good idea. Circular saws are made for high speed, not for high tourge. By useing any type of belt or gear drive you will lose some of both. If you were to still use the saw I'd think a direct drive to the shaft would be better (not much at that). I'd go with the drill like Kiteman suggests.
Actually, circ saws are geared down.

I also suspect that a 2x4 offers up more resistance to spinning than a small prop in water would.
AceOfCircles (author) 5 years ago
Thank you for the feedback. I will find a new source of power.

I was also curious, however, what parts and processes are required to attach a prop and the additional gear to the lower shaft? I go to a school with a machine shop and most of my friends are maritime engineers. I don't mind asking for their help but I would just like to know what I'm talking about and what to ask for first.
I have a feeling that the prop just screws on the the end, with the thread going the opposite way to the usual spin of the prop.

If you have a length of bar, you could use a tap-and-dye set to make it accept the prop.

Or you could make your own prop, welding / gluing on your own blades.
Kiteman5 years ago
If you are fixed on using a power tool, I would use a cordless drill (with loads of spare batteries).

You'll be able to drive a shaft directly, and fix blades to the far end of it.
Kiteman Kiteman5 years ago
(You'd be able to control the speed as well.)
AceOfCircles (author) 5 years ago
I have a portable power supply. It wont last long, but it serves its purpose.

Thank you for your response. I hope you can help.
Toga_Dan5 years ago
how long is the extension cord to power this?