BoatOnCourse.com is an extension of the Safe Boating Council. They have numerous training video's and quizzes for the public. They are a great study resource. Some of their video's are below.
Founded in 1958, the National Safe Boating Council (NSBC) serves as a national catalyst for developing a safe boating culture by providing educational resources, outreach programming, and training opportunities for industry partners and the boating community to influence safe, secure, and responsible boating.
Yes These guys are like AAA on the water, but they are also an excellent education provider.
Magazine, turned educational resource that is published by the National Marine Manufacturers Association. These guys have endless educational articles, and videos.
These guys are the counterpart to the U.S. Olymipc Sailing organization. As such they have developed some excellent educational resources, including video's and articles