Question 1

It's great to have so many models to choose from, but which one should I choose?

Henri · Accepted Answer

If you’re not familiar with weather models, you’re probably wondering which ones to choose.
Here are a few simple rules:

Select the model according to your navigation area and type of sailing, following the table below.

For weather data, if in doubt, choose the ECMWF IFS model.
The ECMWF IFS model covers the entire globe for up to 14 days. However, note that forecast reliability decreases with time:

Forecast range	Reliability level
Up to 2 days	Excellent
2–4 days	Very good
4–5 days	Good
5–8 days	Reasonable trend
8–10 days	Rough trend
Beyond	At best a trend — often unreliable. Prefer the AIFS model, computed using Artificial Intelligence.

Here’s a table to help you choose. We’ll soon add an automatic selection feature based on your sailing program.

Type of data	Type of navigation	France – Atlantic & Channel	France – Mediterranean	Europe (outside France)	United States	Rest of the World
Weather	Day sailing in a bay	Arome	Arome	UKV, ICON, or Arpege Europe	Nam Conus Nest	ECMWF IFS
Weather	Coastal	Arpege Europe	Arpege Europe	UKV, ICON, or Arpege Europe	Nam Conus	ECMWF IFS
Weather	Offshore	ECMWF IFS and AIFS + GFS	ECMWF IFS and AIFS GFS	ECMWF IFS and AIFS GFS	ECMWF IFS and AIFS GFS	ECMWF IFS and AIFS GFS
Waves	Coastal	MFWAM France	MFWAM France	MFWAM	GFS Wave	GFS Wave
Waves	Offshore	MFWAM + GFS Wave	MFWAM + GFS Wave	MFWAM + GFS Wave	MFWAM + GFS Wave	MFWAM + GFS Wave
Currents	Day sailing in a bay	Ifremer	Copernicus Med	Copernicus	MSC NCOM	Copernicus SMOC
Tidal currents	Coastal	Copernicus IBI	Copernicus Med	Copernicus IBI or ENWS	MSC NCOM	Copernicus SMOC
Ocean currents	All	Copernicus IBI	Copernicus Med	Copernicus IBI or ENWS	Copernicus Global	Copernicus Global

Question 2

It's great to have so many models to choose from, but which one should I choose?

Henri · Accepted Answer

If you’re not familiar with weather models, you’re probably wondering which ones to choose.
Here are a few simple rules:

Select the model according to your navigation area and type of sailing, following the table below.

For weather data, if in doubt, choose the ECMWF IFS model.
The ECMWF IFS model covers the entire globe for up to 14 days. However, note that forecast reliability decreases with time:

Forecast range	Reliability level
Up to 2 days	Excellent
2–4 days	Very good
4–5 days	Good
5–8 days	Reasonable trend
8–10 days	Rough trend
Beyond	At best a trend — often unreliable. Prefer the AIFS model, computed using Artificial Intelligence.

Here’s a table to help you choose. We’ll soon add an automatic selection feature based on your sailing program.

Type of data	Type of navigation	France – Atlantic & Channel	France – Mediterranean	Europe (outside France)	United States	Rest of the World
Weather	Day sailing in a bay	Arome	Arome	UKV, ICON, or Arpege Europe	Nam Conus Nest	ECMWF IFS
Weather	Coastal	Arpege Europe	Arpege Europe	UKV, ICON, or Arpege Europe	Nam Conus	ECMWF IFS
Weather	Offshore	ECMWF IFS and AIFS + GFS	ECMWF IFS and AIFS GFS	ECMWF IFS and AIFS GFS	ECMWF IFS and AIFS GFS	ECMWF IFS and AIFS GFS
Waves	Coastal	MFWAM France	MFWAM France	MFWAM	GFS Wave	GFS Wave
Waves	Offshore	MFWAM + GFS Wave	MFWAM + GFS Wave	MFWAM + GFS Wave	MFWAM + GFS Wave	MFWAM + GFS Wave
Currents	Day sailing in a bay	Ifremer	Copernicus Med	Copernicus	MSC NCOM	Copernicus SMOC
Tidal currents	Coastal	Copernicus IBI	Copernicus Med	Copernicus IBI or ENWS	MSC NCOM	Copernicus SMOC
Ocean currents	All	Copernicus IBI	Copernicus Med	Copernicus IBI or ENWS	Copernicus Global	Copernicus Global

Question 3

How do I completely uninstall the app on macOS?

Henri · Accepted Answer

Uninstall the application by moving it to the Trash
Open Finder
- Go to the directory /Users/[user]
- Show hidden files and folders in this directory by pressing "Command" + "Shift" + "." (period) simultaneously.

- Delete the following directory:
/Users/[user]/Library/Containers/eSail4VR
Replace [user] with your Mac username.

You can also use the CleanMyMac application.

Question 4

Glossary of marine terms in NavimetriX

Henri · Accepted Answer

📘 This glossary brings together the main terms used in the Navimetrix application and its FAQs. It helps users better understand concepts related to navigation, routing, and marine weather.

Course Over Ground (COG)

The actual direction of the boat’s movement over the seabed, expressed in degrees relative to true north. It differs from the compass heading when there is drift caused by wind or current.

Speed Over Ground (SOG)

The boat’s actual speed relative to the ground (not the water). Calculated by GPS, it includes the effect of currents.

Heading (HDG)

The direction in which the boat’s bow is pointing, measured relative to true or magnetic north.

True Wind Angle (TWA)

The angle between the boat’s axis and the true wind direction. It is calculated from the apparent wind and the boat’s speed.

True Wind Speed (TWS)

The wind speed derived from the apparent wind and the boat’s speed. It represents the actual wind strength on the sea surface.

Apparent Wind Angle (AWA)

The wind angle felt on board, influenced by the boat’s motion. Measured relative to the boat’s centerline.

Apparent Wind Speed (AWS)

The wind speed felt on the boat, resulting from the combination of the true wind and the boat’s speed.

Velocity Made Good (VMG)

The useful component of the boat’s speed, indicating the effective progress toward the destination or upwind.

Closest Point of Approach (CPA)

The point at which two vessels will be at their minimum distance from each other, based on their current courses and speeds.

Time to CPA (TCPA)

The time remaining before reaching the CPA, used for collision avoidance and AIS alarms.

Bearing

The angle between north and the direction of an observed object from the boat. Used to determine the relative position of a target or coastline.

Depth

The water depth below the keel, measured by an echo sounder. A key parameter for safe navigation.

Waypoint (POI / Waypoint)

A geographic point used to define a route or a key position. In Navimetrix, POIs represent these waypoints.

GRIB File (Gridded Binary)

A standard file format containing numerical weather forecasts (wind, waves, pressure, temperature, etc.).

Isochrone

A curve connecting all possible boat positions at a given time according to the predicted weather conditions.

Routing

The calculation of an optimal route considering wind, waves, currents, and the boat’s performance.

Polar

A performance curve showing the boat’s speed as a function of wind angle and wind strength. It forms the basis for the routing engine.

Estimated Time of Arrival (ETA)

The predicted time of arrival at the destination, calculated from the remaining distance and the average speed.

Sea State

A description of the waves and swell (height, direction, period). Used to assess routing comfort and safety.

Swell

A regular train of waves formed by distant winds. It differs from the wind sea, which is generated locally.

Significant Wave Height

The average height of the highest one-third of waves, the main indicator of overall sea conditions.

Currents

Water movements caused by tides or ocean circulation. They affect the boat’s speed and trajectory.

Tide

Variation in sea level caused by the gravitational attraction of the Moon and the Sun. It influences depth and coastal currents.

It’s great to have so many models to choose from, but which one should I choose?

It’s great to have so many models to choose from, but which one should I choose?

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It’s great to have so many models to choose from, but which one should I choose?

It’s great to have so many models to choose from, but which one should I choose?

Related Posts

How do I completely uninstall the app on macOS?

Glossary of marine terms in NavimetriX

Why are there global models and regional models?

What regional atmospheric models are available for Europe?

Contact

Politique de confidentialité

Conditions Générales d’utilisation