Watercraft safety is a fascinating and complex subject, even for those who don't own a boat. Many of the rules apply to other emergency situations. But undoubtedly it is a top priority for those who own watercraft or spend time around them.
Fortunately there is a great deal of information available to US citizens for free from many accredited organizations and institutions around the country. Most municipalities have some manner of boating safety and training courses and certification available.
The US Coast Guard Auxiliary offers a wide variety of free courses here, you can search by zip code to see what they offer near you.