Just enough to be dangerous
I teach basic boating courses in a state (Rhode Island) that has a Mandatory Education Law (All boaters born after 31 DEC 85 as well as ALL PWC operators) exceptions are made for those operating a vessel of under 10 hp, or from out of state, or new state residents (60 days grace). I believe that EVERY boat operator should take a boating course, one that covers the NAVRULES, basic seamanship, marlinspike seamanship (knot tying), how to plot and follow a compass course, basic engine skills, and weather, plus a few more topics. I was one of those young boaters that Maine Sailor mentions, I was taught by my parents the proper way to handle a boat, and backed that up with both the USPS and USCGAUX courses. I started small, in a 6' sailing/rowing dinghy as well as on our family 21' sailboat. I now have a 17' daysailer and sometimes use our 14' powerboat. If something goes wrong, I'm prepared, and don't panic. Due to my upbringing and experience I could handle larger boats as well, but not until I had practiced away from congested waters.
I can relate to the story about that powerboater who called the CG to report that his boat was on fire when it was actually only a burst cooling hose...the same thing happened a few weeks ago off Marion, MA. 30' Sea Ray, grandfather, grandma, and a small child...they panicked and called in a MAYDAY, what a response! The harbor patrol went out (2 boats from one town, possibly 1 or more from second), the Fire dept. went out (1 boat, 1-3 engines on shore), several good samaritans went out, SEATOW responded.......the boat was hauled out asap, but when I saw her minutes after haulout....no a spec of soot anywhere! I found out the next day that it was steam, not fire.
Back to Mandatory Ed, my experience is that when the law requires education, most people do take a class, but I'd say that over 50% of those would have taken the class anyway. Far too many take the shortest course available that meets the requirements....then decide that they now know all that they will ever need to know! WRONG!! I've been boating for 40+ years, I've taken (2) 13 week (2-hours per week)courses, and have been teaching boating safety courses for 17 years........but guess what? I'M STILL LEARNING! I still don't know all that I need to know!
I wish there was a way to get boaters to WANT to take classes, people who take classes because they want to learn more, will be much safer boaters than those who take a class only because the law tells them to (although, I have seen a few that prove to be exceptions and discover how much they didn't know and then seek out more courses!).
Unfortunately, Common Sense isn't common, and despite the government's best intentions, you just can't legislate common sense!