I purchased my used 18 foot Jon boat and restoring this winter. Since it was a used boat it has seen its share of beaching. All my other boats are semi V's with nice thick keels and I wasn't concerned with beaching. The river I fish has poor launches at best (no docks) so you have to beach each time you go out. I'm a guide on the river so I'm always launching and removing. The 18 footer has 4 keels which are pretty worn. I searched the web for keel guards. A few companies wouldn't recommend using their product on a Jon boat. Until I found Keel Shield https://www.keelshield.com KS Marine Product
These people went out of their way to accommodate me. They sent me a sample of keel guards, and easy to follow instructions, great color selection, and its a life time guarantee. They also make skeg guards, bow guards. I highly recommend them, they stand behind their product!