Make sure that everyone wears a life vest, take it slow until the riders and you get the hang of it, have a designated spotter to tell you if a rider falls off, watch the waves that could throw a young rider, watch out for other boats that might have a driver that is not paying attention. If someone does fall off get back to them quickly as possible.
When getting on and off boat be sure that prop is not under power.
Get wet and have fun.
If the grand kids are too young for skiing you could get a piece of plywood and cut it in a circle and paint it to protect the wood from the water. I learned on a disc at a very early age and I was just messing around on one a few weeks back. They are fun, you can sit, stand, lay down do spins and never go over 5 mph. The rider holds the rope like he is water skiing,
