What we did for our kids was carry a old 10' zodiac ( plywood removable bottom type) and one of the 3hp Tohatsu outboards. In a protected anchorage the kids would putt around and visit other boats and just have a grand time. The grab bag had a horn, a whistle, a flashlight, a handheld vhf, and a extra 1 gallon fuel tank with easy pour spout. Of course the boat was also able to be rowed if necessary.
When they were out cruising around I spent my time on the flybridge keeping a eye out for them, I always had my own RIB ready at a moments notice if trouble arose.. it never did. I figured in a contained anchorage they were pretty safe.. although I was chastised a couple times by overbearing moms that thought it was irresponsible to let them out by themselves. Needless to say they both survived unscathed.
I still chuckle at remembering the day they figured out that they could actually get the dinghy to plane if they hung out over the nose and got the weight distributed just right.. this out of 5-1/2 and a 8 yr. old girls. The independence this fostered probably was part of what has made both of them impressive self assured successful women. They will probably shake their heads when I do the same thing someday with my grand kids!
HOLLYWOOD