Propeller for weed eater / string trimmer

I could use some help to finish this design. Please comment.
My weedeater jammed up at the end, so thought I could use the Motor and shaft to push a boat.
This prop started from the wonderful online here ( hope website never comes down )
https://www.wageningen-b-series-propeller.com/
I matched the size I wanted, horsepower and revs of weedeater, and then set up the blades to print in a strong orientation with minimal support in Fusion360.

I'd like some suggestions how to get the square d