Other Topics: These are short videos about various tips and tricks for navigation.
The 3 and 6 minute rules are handy for quickly determining how far your ship will travel in a given amount of time.
3 minute rule: Your ship's speed (knots) x 100 = Distance travelled (yards) in 3 minutes.
6 minute rule: Your ship's speed (knots) / 10 = Distance travelled (miles) in 6 minutes.
You can also deduce other rules: the 15 minute rule, the 12 minute rule, etc.
Two navigational math rules to determine how far away an object will be at closest point of approach. For instance if you see a lighthouse 6 miles away, and 5 degrees off the bow, how can you determine how close you will be at the closest point of approach?