It's about the worst shape imaginable. I don't know what they were thinking of drawing that shape.
You should aim for a shallow ogival shape at the tip of the blade.
Sharp edges aren't necessarily more efficient and they will damage very easily, especially as your prop is cast from aluminium.
At the end of the day,if efficiency is your goal, you ought to dispense with the original, or keep it for static. You would be better off making some blades fro sheet material, and giving them a true helical twist from hub to tip with a proper ogival blade shape on the back of the blades.
But, the Nautilus is far from an optimum design, it works well enough, but has huge amounts of parasitic drag, and the rakers resultin undesirable handling quirks at speed. If you want efficiency, build a Skipjack or a Valiant.