If you want to become a professional skipper or sailing instructor professional qualifications are required. Certifications that are recognised and respected all over the world are the RYA Yachtmaster certifications. (Costal, Offshore, Ocean) The comparable American qualification is the U.S. Coast Guard Captain’s License.
The exams for these qualifications are very comprehensive. You need a minimum time spent at sea and some pre-certifications are required. There are Internet-links at the end of the book to find information about the necessary conditions.
All Sailing courses: The Taster Course | Beginner’s sailing course | Dinghy beginner’s course | Keelboat beginner’s course | Sailing with others | Starting Yachting | Yachting | Professional Qualifications