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Calculate apparent wind — offline for sailors
What you feel on your face aboard is the apparent wind — the combination of true wind and your own boat speed. NauticCalc converts between apparent and true wind either way, right on the iPhone and without a network.
True or apparent — easily confused
Instruments show apparent wind, the forecast shows true wind. For trim, windward courses and voyage planning you need to keep the two apart — and convert quickly, without long tables.
What NauticCalc delivers
- ·Apparent wind from true wind, boat speed and wind angle
- ·Reverse calculation: true wind from apparent wind and your own boat speed
- ·Result as wind speed and angle — shown so you can follow it
- ·Calculation offline on device — no network needed for core calculators
- ·A support tool — no substitute for calibrated onboard instruments
Offline in the cockpit
The wind calculation runs locally on the iPhone. No account, no cloud — just input and result.
By skippers, for skippers
No subscription, no ads, no login. One-time purchase — all core calculators permanently on device. Data stays on your iPhone.
Frequently asked questions
True wind is the wind over ground. Apparent wind is what reaches you aboard — true wind combined with your own boat speed. On the wind it is stronger and further forward; off the wind it is weaker.
No — the conversion runs offline on the device. Live weather and online tides are separate and optional (BYOK).
No. NauticCalc is a support tool for calculating and cross-checking — it does not replace calibrated onboard instruments.
Related topics
Apparent wind at hand — even without network
Buy once · No subscription · iOS 17.6+
