If you would like to sail properly and safely, there are some skills you are supposed to have:
- ETA calculation (Estimated Time of Arrival);
- Reading of the coordinates of the starting point and the arrival point;
- Speed to be kept;
- Miles calculation;
- Estimate the amount of fuel to be taken on board.
How to measure miles
Measuring miles using a nautical chart is essential. It will allow you to know at what speed you should travel to reach the destination within a given time.
You will also be able to establish the E.T.A. (Estimated Time of Arrival).
To measure miles we can start by plotting the route.
Take a ruler and a pencil and join the starting point to the arrival point by marking a line between them.
After that, use a beam compass (or a regular compass) and open it to the course length.
Now, place the open compass on the latitude scale to the right or left of the chart (it depends on the chart).
The number in primes and decimals of prime that are derived are the number of miles (mile and decimal of mile, then).
How to calculate time and E.T.A.
To calculate the sailing time and the estimated time of arrival, it is possible to make use of the formula triangle.
Translation from Italian
Velocità = Speed
Tempo/minuti = Time/Minutes
Miglia = Miles
In the charting problems of the 12-mile boating license exam, calculations of the speed to be kept, time and time of arrival are required, as well as the calculation of fuel consumption.
Please note: multiplying by 60 gives the time in minutes, while if you don’t multiply you get the amount in hours.
Fuel quantity calculation
To calculate the amount of fuel to be taken on board, you should multiply the estimated hourly consumption by the hours and decimal places of sailing time.
Watch out: do not use time expressed in minutes!
It is convenient to add 30% to your fuel quantity.
Recap
- T=M:V
- Liters of fuel=TxL/hx1.3
- T is always in hours
- To calculate reserve liters (30% of total fuel) we do:
TxL/h:100×30