Navigate

A free online course designed to provide all small boat professionals with the basics of navigation in basic coastal navigation.
http://home.att.net/~agligani/navigation/navigate.html

NavRules

Free formal training program to learn the "rules of the road", required of all boat operators. Internationally recognized Collision Regulations and US Inland Rules.
http://www.navrules.com

Coastal Navigation

Free online advanced navigation course and boating resources.
http://web.inter.nl.net/users/SAILING_Greece/navcourse0.html

Navigation, Boat Handling, Sailing (RYA Yachtmaster course)

Free online slide-show tutorials written by a Yachtmaster instructor. Comprehensive, module-based, and includes titles such as Safety, Weather, and Passage Planning.
http://www.murorum.demon.co.uk/slides.html

International Regulations For the Prevention Of Collisions at Sea

Provides free assistance in learning the International Regulations for the Prevention of Collisions at Sea (Col Regs/IRPCS) and includes links to relevant sites.
http://www.sailtrain.co.uk/Irpcs/