Bill, Thanks for the kind word, this video is targeted towards the everyday sailor, i guess every bit helps. What I found most challenging with the maters exams was getting the 90% grade on the navregs exam. The challenge with the 90% is knowing cold the exceptions in the use of sounds and shapes, and which exceptions are international versus inland or both. Lights can be difficult, I got a little slide rule style quiz tool and my wife used to test me while we were driving somewhere on weekends,...many weekends.