GPS stands for Global positioning System, literally “global coverage system.” It is mandatory to have it on board in navigation beyond 12 miles, but it can help anyone who is about to take a boat in any weather condition and for any trip.
In short: it is almost always advisable to have a GPS, also because it makes it much easier to orient and locate the Ship Point.
Many beginners to navigation are led to believe that GPS is sufficient to orient themselves correctly; in fact, GPS is an excellent aid but it is essential to know the charting elements necessary to be able to at least estimate one’s position.
GPS can break down or may not be powered properly.
That is why it is ideal to properly use a nautical chart and compass and report the position coordinates indicated by the GPS in the nautical chart every half hour or every hour of navigation, depending on the speed held.
How GPS works
There are 24 satellites divided into groups of 4 over 6 circumpolar hours.
Each satellite has within it an atomic clock with a time that is transmitted continuously.
GPS allows one to know one’s position by receiving these signals and measuring the time elapsed between the departure and arrival of the signal, and consequently measuring the speed of transmission, and finally calculating the distance.
The result that GPS provides is the satellite Ship Point, which is the latitude and longitude of one’s Ship Point with a very small margin of error.
In navigation, we have a waypoint, which also indicates a course, but more importantly, it indicates the actual speed and estimated time of arrival.
More advanced GPSs are also capable of warning of hazards on the route and giving directions on the way ahead that can be considered alternatives to navigation signals.
A very important function of modern GPSs is the MOB (Man Over Board) button. In the event of a man overboard, this signal is activated immediately and keeps the position of the castaway in memory; it also indicates the distance and course to be taken to reach the man overboard.
A word of advice
GPS is very important for knowing where your ship is.
Estimating your course is easier with a GPS, as well as understanding where there are any dangers marked on nautical charts or marked by the GPS itself. But GPS is also useful for estimating the course and avoiding mistakes.
However, if you need to obtain a boating license and if you want to specialize in navigation, you need to master the elements of charting and recognizing conspicuous points around them. You should also be able to detect any other elements, such as navigation signals, that indicate how to navigate safely.