What happens to the currents?

Current data is usually displayed on instruments as “Direction and Speed”. However, to calculate currents we need geographic position data or a GPS.

Currents are calculated by looking at the difference between where the GPS says we are going (relative to the bottom) and where the instruments think we are going (relative to the water, without taking currents into account).

Why Speed ​​and not Drift?

A very common mistake (even among experts!) is to refer to the speed of the current as drift, when the correct term to use is speed . Drift is the distance an object travels in the current during a given period of time. Since both terms are used quite commonly, there should be no confusion if the wrong one is mentioned.

The direction of the current is the direction toward which the current flows. It is important to distinguish between a northerly current and a northerly wind direction. A wind blowing north means that the wind is blowing from the North; while a north current direction means that the current flows toward the North.

For safe passage, it is crucial to understand the effects of currents.

• Effect on the ship: There will be a difference when comparing Heading and COG, Ship Speed ​​and SOG. The direction and speed of the current can be calculated by the difference between these values.
• Effect on water: The current can agitate or smooth the sea depending on the Direction of the Actual Wind. For example, Wind Against Current generates large waves, making entering some ports dangerous, if not impossible!
• Effect on Wind (Actual): The True Wind decreases if the current takes us to leeward, but increases if the current pushes us to windward.

And that's the end of our advice for this week, but don't miss the next chapter where we will go a little deeper into the topic of “Meteorology”, see you soon.