Weather data access and GRIB files were extensively discussed in the Global Solo Challenge (GSC) WhatsApp chat, covering regulatory requirements, data sources, satellite communications, routing strategies, and concerns about cost and reliability.
1. Official Requirements for Weather Data in the GSC
- Skippers are responsible for obtaining weather forecasts and routing decisions.
- External weather routing is permitted, unlike other offshore races such as the Vendée Globe and Globe 40.
- Reliable satellite communication is essential to download GRIB files, access forecasts, and stay updated on changing conditions.
- Backup methods for retrieving weather data are highly recommended to avoid reliance on a single system.
2. Commonly Used Weather Data Sources
The discussion covered different sources for weather forecasting models, with skippers debating accuracy, efficiency, and data consumption.
2.1 GRIB File Providers
- Saildocs: A popular choice for low-bandwidth GRIB file requests, optimized for slow connections like Iridium.
- PredictWind: Used by some.
- Squid Sailing: Provides access to multiple weather models in one package, favored by some participants.
- OpenCPN + Sailmail: Budget-friendly software for downloading and displaying weather forecasts.
2.2 Weather Models Used in Routing
- GFS (Global Forecast System)
- ECMWF (European Centre for Medium-Range Weather Forecasts)
- ICON (German Model)
- ARPEGE (French Model)
- UK Unified Model (UKV) – Only accessible via Expedition.
3. Satellite Communication and Data Consumption
3.1 Starlink vs. Traditional Satcoms
- Starlink: Great but power hungry with the big antenna. Mini antenna may be better. A backup for weather data must be available.
- Iridium GO!: Reliable but extremely slow. Requires testing of how to actually get weather data that is not too heavy.
- Inmarsat & KVH: High-cost options ($2,000/month) used in professional racing but not common in GSC due to cost.
3.2 Data Consumption and Cost Control
- Some skiper consult weather through Windy.com which can only be used with Starlink and was criticized for excessive data usage, requiring hundreds of MB per day.
- GRIB files can be optimized to under 1MB/day, making them manageable for slow satellite connections.
