Support

TideCatch calculates predictions on your iPhone from official harmonic constants. Small differences (usually a few minutes or centimeters) come from rounding, a different nearby station, or subordinate stations that are derived from a reference station. Each station page shows its data source, datum and measured accuracy. If a station looks wrong, open the station page and tap "Report inaccurate tide".

These are astronomical tides. Wind, air pressure, storms and river flow can raise or lower the water and shift the timing. Not for navigation.

The United States (including Hawaii, Alaska, Puerto Rico and Guam), Japan and South Korea. The fishing log works anywhere.

Yes. Tides, the calendar, widgets, alerts and the fishing log all work offline.

Touch and hold the Home Screen or Lock Screen, tap Edit › Add Widget, and choose TideCatch. To pick a station, touch and hold the widget and choose Edit Widget. The large widget shows a full week.

No. Pro is a one-time purchase with no renewal and no trial that turns into a charge. It works with Family Sharing. To restore it on a new device, tap Restore Purchases on the Pro screen or in Settings. Refunds are handled by Apple at reportaproblem.apple.com.

With Pro, turn on iCloud sync on both devices. Without Pro, go to Settings › Backup › Export Backup, send the .tidecatch file to your new iPhone (AirDrop, Files or email) and open it. An iPhone-to-iPhone transfer or an iCloud device backup also includes your data.

Only you. There is no account, community or public map. Spots are stored on your iPhone and, with Pro sync, in your own iCloud. Shared catch cards hide the location unless you choose to show the general area.

Settings › Anonymous statistics. Deleting the app deletes all data on the device. See the Privacy Policy for server data.

US heights are measured from MLLW (mean lower low water), so a negative height means the water is lower than an average low tide – good for clamming. Japan uses the 潮位表基準面 and Korea the 약최저저조면.