1. What is Great Circle Distance?

The Great Circle Distance is the shortest distance between two points on the surface of a sphere. For sailing navigation, this represents the most efficient route between ports, following the curvature of the Earth.

2. How Does the Calculator Work?

The calculator uses the Great Circle Distance formula:

Where:

• \( R \) — Earth's radius (3440.065 nautical miles)
• \( lat_1, lon_1 \) — Latitude and longitude of departure port
• \( lat_2, lon_2 \) — Latitude and longitude of arrival port
• All coordinates converted from degrees to radians

Explanation: The formula calculates the central angle between two points on a sphere and converts it to distance using Earth's radius.

3. Importance of Sailing Distance Calculation

Details: Accurate distance calculation is crucial for voyage planning, fuel estimation, arrival time prediction, and navigation safety in Greek waters.

4. Using the Calculator

Tips: Select departure and arrival ports from the dropdown menus. The calculator will instantly compute the nautical mile distance between selected Greek ports.

5. Frequently Asked Questions (FAQ)

Q1: Why use nautical miles instead of kilometers?
A: Nautical miles are the standard unit for marine and air navigation, based on one minute of latitude (1 NM = 1.852 km).

Q2: Is this the actual sailing distance?
A: This is the great circle (shortest) distance. Actual sailing distance may vary due to weather, currents, and navigational constraints.

Q3: How accurate is the calculation?
A: Very accurate for planning purposes. Small variations may occur due to Earth's ellipsoidal shape.

Q4: Can I add custom ports?
A: Currently only major Greek ports are included. The calculator uses predefined coordinates for accuracy.

Q5: What's the typical sailing time for these distances?
A: At 5 knots, approximately 1 NM = 12 minutes. At 10 knots, approximately 1 NM = 6 minutes.