Help and product information for Amphidrome.
Amphidrome is a harmonic tide and current almanac that does its math entirely on your device. Every prediction is computed from bundled tidal harmonic constituents — the same physics professional almanacs use — so it works exactly where cell service dies: a back-bay cove, an offshore bank, a canyon river mouth, or airplane mode.
Does the app need an account or subscription?
No. It is a one-time-download app with no account, advertising, analytics, or in-app purchase.
Does it work offline?
Core features and bundled reference data work on-device without a developer-operated service.
Where is my information stored?
Your station favorites, almanac selections, and prediction preferences remain in the app's local storage.
How do I remove local data?
Use available delete or reset controls. Removing the app removes its local container, subject to backups you control through Apple.
What are the limits?
Predictions are planning aids and are not approved for navigation or emergency decisions. Use official local tide and current information when safety matters.
Email support@shadowfetch.com with the app name, device model, iOS version, and a concise description of the issue.