I was just looking at my boating gear after vacation and found a plastic emergency prop.  It came with the boat along with two stainless props when I purchased it.  I had forgotten about it.  

Anyone have one or have info on them?  I seem to remember being told that you shouldn't use it at speeds exceeding 20mph? Better than getting stranded for sure.....

I keep it in the back of the boat by the gas tank and batteries.  I had just forgotten it was there.  

    I would think just the force of water going along the prop could bend.

    I really don't know though, just throwing out a random idea.

It depends on the type of plastic. Its just meant to get you home and not more than get you home. Probably fine for that purpose.