In reply to David Coley:
Tidal data is put together (from memory) by the UK Hydrographic office (UKHO), they allow free access upto seven days in advance from the current date.
Publishing their tidal predictions beyond that is a copyright offence unless a licensed reseller, which might have been why the CC stopped. A number of websites and other organisation faced a clamp down.
You can get ‘quick tide’ calculators, but the further ahead the larger the error, as it’s not a simple task/shift. Tide predictions vary depending on extrapolation method used, tidal data available, and the constant from Dover isn’t static varying a bit from springs to neaps in many places, plus the natural change in tide. Accurate prediction thus requires complex algorithms, which unsurprising the UKHO & The Admiralty have.
But what I’m trying to say is if you are looking a couple of years ahead without paying, using a free source, adjusting by a constant, the time of HW could be out by maybe an hour, possibly more.
A quick search without pointing you to expensive tomes gave this simple list of Tidal constants from Dover for a variety of ports as a starting point:
https://www.wansbeckpaddlesports.co.uk/tidal-constants
I have no knowledge of how accurate it is, as mentioned above getting an old sailing almanac would also give constants.
Its easier just to buy the tides. £3.50 for the whole of the UK for a year is stunningly cheap, not that long ago tide tables for a just couple of ports would cost that.
As for UKHO 2023, I’m not sure when they will be issued at a price for the likes of you and I, but shouldn’t be too long as we are getting to year end.
Post edited at 00:07