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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 the device — no network for the core calculator
- ·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 stay on the device for good. Your data stays on the 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+
