Obtain your Navigation License (old "Titulín") in the Entrepeñas reservoir and start sailing in a single day. Only surpassing this course of 6 hours (2 theoretical and 4 practical), you can already obtain your license. There is no exam.
The Navigation License allows you to govern boats of up to 6 meters in length at a distance of 2 miles from the coast, during the day. It also allows you to drive jet skis with no power limit.