Minimum age for tubing

[cillovely]

Forgive me if this has been discussed before, I can't seem to find anything on it.

I was just curious as to what the minimum age is to pull someone on a tube. I know you need a spotter 13 years or older and it can't be the driver, but I don't know how old you have to be to be on the tube itself.

Thought of this yesterday as I was pulling my son around in our pool on his boogie board.