NavList:

Thank you David_P for the Brough Tide page image. It was rewarding to double check all the manual numbers that I had typed in to do the "accuracy of a Tide Clock at Brough" were indeed, ALL the same as your Tide Table. 

One has to be careful with online Tide Data though David, because I found this web page that has the Brough Tide, except ALL the numbers are different to the Official Tide! I'm assuming someone was using a "nearby port" and using a constant delta to give the Brough Tide (commonly known as a Secondary Port) - which can often go wildly astray as indeed does a Tide Clock.

David_P wrote:

> I’ve concluded that safest, most accurate method is to tweak them to the tables before every tide.

That will keep you on your toes David, tweaking the hands of a Tide Clock every 12 hours 25 minutes for the rest of eternity ;-)

I have seen the four handed Clocks advertised David, but never bought one. I *assume* they have a 2^15 (32,768 Hz) quartz crystal and then plastic gearing for the Tide dial. If that is true, I would again *assume* that they are not as accurate as the modules that have a Quartz Crystal cut to the Lady Moon (hat tip to Kermit) M2 speed constant.

Will look forward to receiving my Gold Star David, and also your findings after opening up your two types of Tide Modules.

I just checked, and I still have 5 new Tide Modules I haven't used yet - so I might sacrifice one, and see how it works, and use my GPS timing project to determine the frequency of the Quartz Crystal Oscillator.

Thank you Bob_C for the PDF on the River Humber, it was an interesting read. Although I have never visited it, the River Humber lives rent free in my head because of the association with the famous "John Harrison" - who enabled Modern Celestial Navigation with the invention of a reliable sea going timepiece. John Harrison did his main work at "Barrow upon Humber", just 14.5Km (as the crow flies) from the Humber Yawl Clubhouse - across the river Humber.

Bob, I did track down a source of "machine readable tide data", it is from the Official Body for managing the "UK Tide" -  "UK Hydrographic Office". The bad news is, they charge 30 English Pounds for an ASCII file of just a single year and a single station - which is out of range of my hobby budget. Whereas in the USA and New Zealand (and probably many other countries) the plain ASCII tide data is completely free of charge to download !

To hopefully receive another Gold Star from David_P - I will send this message on its way, at the very instant of the Equinox:

March 20th 2024, 4:06pm NZDT ( = UTC +13 Hrs).

Regards, Geoff Hitchcox, Christchurch, New Zealand.