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FastSeas is a weather routing and passage planning tool for sailors. It calculates the fastest and most comfortable route between two points using NOAA GFS and ECMWF weather forecasts, ocean surface current data, your vessel's performance, and your own comfort criteria.

Frequently Asked Questions

What weather forecast does FastSeas use?

FastSeas uses the latest NOAA GFS and ECMWF model data when calculating routes. GFS covers the next 16 days and ECMWF the next 15, and each route reports which forecast it was calculated from.

Does FastSeas consider the effects of current in calculating the best route?

Yes, FastSeas uses the latest available NOAA RTOFS ocean current forecast when calculating routes. The current is forecast for about 8 days ahead and changes over the course of your passage, and FastSeas takes that into account. The routing algorithm will automatically route you through areas of beneficial current, and avoid areas of contrary current.

When are the GFS forecasts updated?

NOAA publishes GFS model data four times a day. The approximate times that FastSeas acquires these new data are shown below:

• 05:25 - 05:45 UTC for the 00z forecast
• 11:25 - 11:45 UTC for the 06z forecast
• 17:25 - 17:45 UTC for the 12z forecast
• 23:25 - 23:45 UTC for the 18z forecast

When are the ECMWF forecasts updated?

ECMWF publishes its high-resolution forecast four times a day, but the four runs are not equivalent: the 00z and 12z runs reach 15 days ahead, while the 06z and 18z runs are shorter supplementary forecasts reaching only 6 days. FastSeas uses all four. The 06z and 18z runs are extended to nearly 15 days with the later part of the 00z or 12z run before them, eased onto over one day, so every ECMWF forecast reaches about as far ahead and the first 6 days are always the newest run. The approximate times that FastSeas acquires these new data are shown below:

• 07:40 - 07:50 UTC for the 00z forecast
• 12:40 - 12:50 UTC for the 06z forecast
• 19:40 - 19:50 UTC for the 12z forecast
• 00:40 - 00:50 UTC for the 18z forecast

Like GFS, ECMWF is refreshed four times a day, but each run arrives later than the equivalent GFS run: about an hour later for the 06z and 18z runs, and about two hours later for the 00z and 12z runs.

When is the ocean current forecast updated?

NOAA runs the RTOFS ocean model once a day, from 00z. NOAA publishes the full 8-day forecast in the afternoon, and FastSeas usually acquires it between 15:20 and 15:40 UTC.

How does FastSeas calculate passages that exceed the forecast duration?

When the voyage duration exceeds the forecast duration, FastSeas continues to calculate the voyage using the last available weather forecast data. FastSeas will display warnings in the results and plot this extended portion of the voyage with a dashed line. The ocean current forecast is shorter than the weather forecasts (about 8 days), and past its end FastSeas likewise keeps using the last available current forecast. Only the weather forecast triggers the warnings and the dashed line.

How do I delete my account?

Open Settings in the app and choose Delete Account. This permanently deletes your account, your saved routes and departure plans, and your vessel settings, and cancels any active subscription. It cannot be undone. See our Privacy Policy for what is kept afterwards and why.

Offshore, with no internet?

FastSeas can also return routing and departure planning results by email or satellite communicator (Garmin inReach, Iridium GO!, Zoleo, and others). See Using FastSeas by Satellite Email for details.

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FastSeas is a dba of Extempo LLC, 30 N Gould St Ste N, Sheridan, WY 82801-6317, US.