How to Determine Opening and Closing Angles Using the 1 in 60 Rule

To calculate the opening and closing angles using the 1 in 60 rule, you’ll need the following:

1. The constant 60
2. Distance traveled
3. Distance off track
4. Total trip distance

Example

• Trip Total Distance: 190 NM
• Distance Traveled: 110 NM
• Distance Remaining: 80 NM
• Distance Off Track: 9 NM

Formula:

• Opening Angle = (60 ÷ Distance Traveled) × Distance Off Track
• Closing Angle = (60 ÷ Distance Remaining) × Distance Off Track

Calculations:

• Opening Angle = 4.9° (rounded to 5°)
• Closing Angle = 6.75° (rounded to 7°)

Heading Correction

To correct your heading, adjust by the total of the opening and closing angles. In this case, you’ll need to alter your course by 12 degrees left or right, depending on whether you’re left or right of the track.