Launch TideHelm — the Today tab loads immediately with no sign-in. Tap the station header at the top of any screen to select the NOAA station closest to you. Swipe or tap the tab bar to move between tools.
Support · v1.3
TideHelm Support
Help, troubleshooting, and contact information for TideHelm.
TideHelm requests no permissions at launch. Location access may be offered in a future update to auto-select the nearest station. No location data is stored or transmitted.
Email the App Store product page with your iPhone model, iOS version, and a short description of what happened.
Common Questions
Does the app work offline?
Yes — all tide predictions, astronomical calculations, tidal coefficients, anchor scope math, and reference data run entirely on-device. No internet connection is needed.
What is the Tide Table (Almanac)?
The Almanac tab (new in 1.3) shows every High and Low tide event for the next 7 days in a tabular format — time, height in feet, and height relative to mean sea level. You can filter to a single day or view all 7 at once. Tap the share button (or the icon in the top-right corner) to generate a plain-text tide table you can paste into Messages or email.
How does the Slack Water Countdown work?
The Today tab now shows a live countdown in the tidal events card ("2h 14m to slack water"). It updates each time you open the app. When slack is under 30 minutes away, a "SOON" badge appears so you can plan your crossing or dive entry.
How are Trip Leg Distances calculated?
The Trip Planner (new in 1.3) computes the great-circle distance between consecutive stop station coordinates using the haversine formula. The distance in nautical miles appears on each stop card and is summed in a Route Summary card at the bottom. This works offline because TideHelm stores the coordinates of each stop at planning time.
What is the Tidal Coefficient?
The tidal coefficient (20–120 scale) describes how strong a tide is relative to the maximum possible astronomical tide. Values ≥ 90 are spring tides with strong currents; values ≤ 45 are neap tides with gentle currents. The Coefficient tab shows a 28-day bar chart of the spring/neap cycle.
What is the Rule of Twelfths?
A traditional navigator's method for estimating water height at any point during a rising or falling tide without a chart. The Coefficient tab includes a live calculator: enter your low and high tide heights and hours elapsed since low, and it returns an estimated depth with a full 6-hour breakdown table.
How do I use the Anchor Scope Calculator?
Open the Anchor tab. Set the charted depth at your anchorage (the tidal range is auto-filled from the active station), bow height, hull length, and the rode you plan to deploy. The swing-circle diagram and holding-quality indicator update instantly.
Does the app require an account?
No. TideHelm is designed for local on-device use only.
Where is my data stored?
Trip plans, fishing logs, and all settings are stored only on your device.
How do I remove the app?
Delete the app from your device in the normal iOS way. All locally stored data is removed by iOS when the app is deleted.
How accurate are the tide predictions?
TideHelm uses a five-constituent harmonic model (M2, S2, N2, K1, O1) tuned to each bundled NOAA station's published mean range. Accuracy is suitable for passage planning and window identification; always cross-check against official NOAA predictions for navigation-critical decisions.