It seems odd to post a link to a learn to sail book here, but I 've just come across a free download book from the new service Boating Hub that may be useful. The book explains the systems for learning to sail in every country that has an accreditation system and what the relevant certificates are. It 's the best overview of how the different international certifications relate to one another that I have found.

http://www.theboatinghub.com/ebooks/Learn-To-Sail.pdf

Vice Commodore, OCC