Isochronal Router (ECMWF)

Drag Start & Finish on the map. Paste your polar.
ECMWF via Open‑Meteo (no key).

Waypoints

Start lat Start lon Finish lat Finish lon

Supported: TWS,TWA,BSP or TWA,BSP. Interpolated over TWA and TWS.

Hours Δt (min) Heading step

Upwind no‑go (°) Min turn to count (°) Manoeuvre penalty (min) Show isochrone lines

Tack/gybe: if heading change ≥ Min turn, a time penalty is applied for that step. Headings with TWA < no‑go are skipped.