Tides are inaccurate
Why can’t they just use tide times for your current location.
Having set it on full moon springs, it was immediately half an hour out making it unreliable
Response from developer
The actual tide depends on the exact position and may (depending on topographical conditions) be subject to strong deviations from the normal rhythm. Therefore, an app like Ship's Bell can only give a value as it can also be calculated with the usual tide tables.