LINK:

http://www.sailingissues.com/navcourse0.html

"Navigation
course

Introduction
This is an advanced online course on marine navigation, providing you
with the 'conditio sine qua non' of offshore sailing. Nowadays most
sailors tend to rely on modern equipment like differential GPS or
Radar to navigate them through hazardous waters."

"Chapter 1 - Positions
Chapter 2 - Nautical Chart
Chapter 3 - Compass
Chapter 4 - Plotting
Chapter 5 - Piloting
Chapter 6 - Tides
Chapter 7 - Tide Prediction
Chapter 8 - Currents
Chapter 9 - Navigation Aids

Math - Running Fixes
Math - Distance of horizon
Math - Vertical sextant angles

Compass Deviation table
Lunation - phases of the moon

The Wind Chill forecast
Beaufort wind scale
Sailing schools and yacht charters in Greece and Turkey
Blurbs
This course deals with the key cognitive issues associated with the
art and science of navigation and communicates them with well crafted
prose and exceptional clear graphics.
I found this online material quite valid for our local US sailors &
instructors and I strongly recommend it as a splendid teaching tool.
Ralph Naranjo
Safety at Sea Committee Chairman US Sailing"