Wind Shift

Wind Shift is a sailing navigation game where you race real fleets on their own courses, in the weather they actually sailed in, using only the forecast they had.

Wind Shift puts you in a race that already happened, against the boats that sailed it. The fleet replays from its recorded AIS tracks (the position signals boats broadcast). The weather is the real wind for that day, from ERA5 hourly data, and you plan from the GFS forecast as it was issued. Before the start you pick a start time and place waypoints around the light air on the forecast. Once the clock runs, your boat measures the real wind within 2 nautical miles of it, and that wind sets your speed. The forecast can be wrong, so you watch for shifts and change course as you go. Your boat sails to its polar, the chart of its speed at each wind angle and wind speed, and sail trim is always perfect, so every decision is about navigation. Two ideal boats race with you: one plans with perfect knowledge of the wind, and one plans from the forecast. The game ships with the 2024 Queen’s Cup across Lake Michigan and the 2025 Spinnaker Cup from San Francisco to Monterey. It runs in a web browser with nothing to install.

AI Game