1. Introduction
2. How to Read Sailing Coordinates
3. Degrees
4. Minutes
5. Tenths of a Minute
6. Seconds
7. Calculating Distance Between Two Points
8. Latitude and Longitude
9. How to Use a Chart Plotter
10. Keeping Track of Your Position with a GPS Receiver
11. Conclusion

How to Read Sailing Coordinates

For those interested in chart navigation, it is important to have an understanding of sailing coordinates and the scales used to locate them on a chart. This article will cover the basics of reading sailing coordinates, including degrees, minutes, tenths of a minute, and seconds; as well as how to calculate the distance between two points with latitude and longitude; how to use a chart plotter; and keeping track of your position with a GPS receiver.

Degrees

When chart plotting, the scales on the right or left side are used to find latitude and longitude coordinates (also known as ‘waypoints’). These scales are broken down into degrees, minutes, tenths of a minute, or degrees minutes and seconds. One degree of latitude equals sixty minutes; one minute of Latitude equals sixty seconds.

Minutes

Minutes are measured in fractions – for example, 30″ would be read as 30 minutes (or 0.5 degree). Similarly, 15′ would be read as 15 minutes (or 0.25 degree).

## Tenths of a Minute
Tenths of a minute can also be used in chart plotting – these are represented by three digits followed by an apostrophe (‘) – for example, 50’ would be read as 50/10th’s (or 0.05 degree). When calculating distances between two points on a chart plotter or GPS device, tenths can also be used – 50″ / 6 = 0.8 (rounded off).

## Seconds
Seconds are also used when calculating distances between two points on a chart plotter or GPS device – they are represented by three digits followed by an apostrophe (“) – for example, 50″ would be read as 50 seconds (or 1/60th degree). When calculating distances between two points on a chart plotter or GPS device, seconds can also be used – 50” / 6 = 0.01667 (rounded off).

## Calculating Distance Between Two Points
When using latitude and longitude to calculate distance between two points on a chart or GPS device, the formula is: Distance = 60 x √(lat2–lat1)^2 + (long2–long1)^2 where lat1 is the starting point latitude and lat2 is the ending point latitude; long1 is the starting point longitude and long2 is the ending point longitude; and Distance is in nautical miles..

## Latitude & Longitude
Latitude is measured north/south from the equator in degrees from zero to ninety degrees either side – zero being at the equator while 90 degrees north equals the North Pole while 90 degrees south equals the South Pole.. Longitude is measured east/west from Greenwich in England in degrees from zero degrees at Greenwich while 180 degrees east equals 180 degrees west..

## How To Use A Chart Plotter
A chart plotter uses electronic charts that allow you to locate waypoints such as harbours, anchorages etc., using both latitude & longitude coordinates as well marking courses between waypoints.. The courses are then plotted onto an electronic map so you can follow them easily.. The data displayed on screen shows your current position against any set course you have plotted.. It also allows you to zoom in/out for detailed viewing..

## Keeping Track Of Your Position With A GPS Receiver
A GPS receiver uses satellites orbiting around Earth which send out signals which can be picked up by devices like your mobile phone or any other compatible device.. This information then helps you keep track of your position relative to any set course plotted onto your chartplotter.. It will also show you current weather conditions such as wind speed/direction etc., which may affect your navigation decisions..

## Conclusion
In conclusion this article has hopefully provided an introduction into reading sailing coordinates correctly with regards to understanding their breakdown into Degrees, Minutes & Tenths/Seconds; calculating distance between two points using Latitude & Longitude; using Chart Plotters & keeping track of your position using GPS receivers.. Being aware of these basics will help make sure that navigating via charts becomes second nature!