One of the main tasks for any boatmaster is to determine the location of the vessel. There are several ways to find out where the ship is. They differ in both the degree of accuracy and the complexity of the navigation devices and instruments used. Let's consider one of the methods, the most simple and does not require complex special equipment.
- - ship's log;
- - a map of the navigation area;
- - navigation area navigation;
- - compass;
- - chronometer;
- - log (a device that determines the speed of the vessel);
- - wind blower (a device that determines the wind speed);
- - navigational line;
- - protractor;
- - compasses;
- - pencil.
How to find out where the ship is by reckoning the movement of the vessel. This method is usually used in open navigation when visual and radar methods of determining the position of the vessel are impossible. It requires a strict record of all changes in the ship's course and speed over time and carefully plotting the route on the map. Use the rotating compass card to determine the ship's course (the deviation of the magnetic needle from north in degrees).
Align the zero mark on the base of the protractor and the mark of the course on its arc on the map with the meridian closest to the point of the last position of the vessel. Attach a chart ruler to the protractor. Without changing the position of the ruler, remove the protractor.
Holding one bar of the chart ruler, bring the other to the point of the last definition. From this point, in the direction of travel, draw a line with a pencil. This will be the ship's heading line.
After taking the chronometer reading, calculate the interval since the last measurement. Read the lag meter and multiply the boat's speed by the time elapsed since the last measurement to calculate the distance traveled.
On the scale bar of the map, measure the distance obtained with a compass. With one leg of the compass set to the last point of the boat's position, score the other on the course line. The crossing point will indicate the ship's position, excluding wind and current corrections.
To calculate the correction for the current, select the data on its direction and speed from the pilot corresponding to the sailing area. Using item no. 2 and item no. 3, draw a flow direction line from the last obtained point. Given the speed of the current, calculate the drift distance using # 4 and # 5. Using # 6 and # 7, apply the demolition point.
Calculate the wind correction in the same way as for the current. Determine the direction of the wind using a compass. Since the wind blows "into the compass", and the direction "from the compass" is plotted on the map, add 1800 to the wind direction. Determine the wind speed with a wind blower. Draw the wind line from the drift point. The drift point will be the true location of your boat.