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Thread: UK Tides Times

  1. #31
    Join Date
    May 2012
    Location
    Second Coast, Ross-shire, overlooking Gruinard Bay.
    Posts
    7,467

    Default Re: UK Tides Times

    Quote Originally Posted by cpedw View Post
    That's just the sort of place where this can occur. As a more pronounced example, look at the Falls of Lora at the entrance to Loch Etive. The Falls is (are?) narrow and mostly quite shallow, leading into 20+ miles of Loch Etive, generally much deeper and wider than the Falls. The flow at the Falls changes direction about 2 hours later than local high/low water.
    I'm not sure but I think the topology around Ullapool and Loch Broom is similar if on a smaller scale.
    Because of the constriction of the flow at the Falls, as the level outside the loch moves up or down tidally, water tries to get in or out of the loch in sync but the rate is restricted so, as high tide is reached, the level in the loch is below the outside sea level so, even as the tide falls, the level outside is still higher than the loch level for some time so the flow continues in until the level in the loch matches the sea level outside.

    I thought that would be a simple explanation but now I'm not sure.

    Derek
    A good example of "flow after high/low tide point", thank you.

    I suppose that the huge difference between the flow I experienced past the Buckle Point buoy at the time of dead tide and the scary flow at the Falls of Lora is indeed due to the almost incomparable difference in topography.

    Loch Broom inland of the buoy is about 5nm long with depths up to 50 metres and the "narrow" point at the buoy is about 0.6nm wide with c.20.5m depth.

    Loch Etive is about 15nm long with depths up to 145m; the Falls are about 0.01nm wide with depths around +1.7m to -6m

    Even my schoolboy maths explains that that would lead to a gigantic difference in performance !!
    (all depths at low tide, taken from Navionics)

    Kay Sarah Sarah
    57°51.42' N 5°29.44' W

  2. #32
    Join Date
    Feb 2013
    Posts
    2,181

    Default Re: UK Tides Times

    tides4fishing.com is good.

  3. #33
    Join Date
    Dec 2018
    Posts
    28

    Default Re: UK Tides Times

    Going back to the original premise: How to work out what the tides will be some weeks or months in advance, given that the free online sites usually only forecast 7 days ahead; can I offer what follows? If anyone thinks I’m miles off, then I’d welcome corrections:

    Step 1. Look ahead to the period that you are interested in, call it ‘Date X’. Find the moon phase on Date X - online sites do provide that sort of information many moons (boom boom) in advance. If your chosen date doesn’t fall exactly on full, new, half waxing or half waning, then applicate a number of days before or after one of those obvious moon phases.

    Step 2. Using the same moon phase site, look around your current date (minus 22.5 / plus 7 days) and find the date that has the same moon phase (or number of days before or after) as Date X; call this ‘Date Y’.

    Step 3. Go to your free online tide site and look at Date Y (note that although most free online sites only look forward 7 days, they do seem to go back about a month or so, though I’ve not looked into this depth). The tide times on Date Y will be very close to the tidal times on Date X. The tidal heights might be off because of the periodic variations in earth-lunar distance and earth-sun distance, but if it was (say) 3 days after Springs on Date Y, it will also be 3 days after Springs on Date X.

    Alternatively, go to your desired Date X in your diary and count backwards in 29.5 day chunks. When you get to a date that’s close to you (minus 22.5 / plus 7 days) note that as Date Y, click into your free online tide site on Date Y and you have the same result (and same caveats) as above. For obvious reasons this is much easier if you’re only forecasting a month or two in advance.

    Sorry about the noddy step-by-step description, but I couldn't find an eloquent piece of prose to describe how I do it! Shout me down if you think I’m wrong, but it’s a system that works for me. I’ve never taken the time to cross check against an Almanac at the planning stage, but I’ve also never pitched up and found the tides doing anything horribly unexpected…

  4. #34
    Join Date
    May 2007
    Posts
    39,131

    Default Re: UK Tides Times

    Quote Originally Posted by Steveberry View Post
    Going back to the original premise: How to work out what the tides will be some weeks or months in advance, given that the free online sites usually only forecast 7 days ahead; can I offer what follows? If anyone thinks I’m miles off, then I’d welcome corrections:

    Step 1. Look ahead to the period that you are interested in, call it ‘Date X’. Find the moon phase on Date X - online sites do provide that sort of information many moons (boom boom) in advance. If your chosen date doesn’t fall exactly on full, new, half waxing or half waning, then applicate a number of days before or after one of those obvious moon phases.

    Step 2. Using the same moon phase site, look around your current date (minus 22.5 / plus 7 days) and find the date that has the same moon phase (or number of days before or after) as Date X; call this ‘Date Y’.

    Step 3. Go to your free online tide site and look at Date Y (note that although most free online sites only look forward 7 days, they do seem to go back about a month or so, though I’ve not looked into this depth). The tide times on Date Y will be very close to the tidal times on Date X. The tidal heights might be off because of the periodic variations in earth-lunar distance and earth-sun distance, but if it was (say) 3 days after Springs on Date Y, it will also be 3 days after Springs on Date X.

    Alternatively, go to your desired Date X in your diary and count backwards in 29.5 day chunks. When you get to a date that’s close to you (minus 22.5 / plus 7 days) note that as Date Y, click into your free online tide site on Date Y and you have the same result (and same caveats) as above. For obvious reasons this is much easier if you’re only forecasting a month or two in advance.

    Sorry about the noddy step-by-step description, but I couldn't find an eloquent piece of prose to describe how I do it! Shout me down if you think I’m wrong, but it’s a system that works for me. I’ve never taken the time to cross check against an Almanac at the planning stage, but I’ve also never pitched up and found the tides doing anything horribly unexpected…
    If you want to know 'near enough' for vague planning purposes, springs are 2 days after a full moon etc, and Springs are at noon and slinging-out time in Portsmouth, breakfast and tea time in Plymouth.
    It's not hard to get the big picture.

    If you need to publish a schedule of races, with local HW times for all of next year, it's harder to get good data that won't result in someone whingeing you've published HW Boghampton-on-Sea 12 minutes out.

    Decide what you need, then if necessary, pay for it and be happy.

  5. #35
    Join Date
    Jul 2014
    Location
    Sail on the Medway, Kent from Chatham Maritime Marina
    Posts
    1,972

    Default Re: UK Tides Times

    Peel Ports have published their 2020 tide tables for these ports they run. May help some people.

    Chatham
    https://www.peelports.com/media/4883...rness-2020.pdf

    Clyde
    https://www.peelports.com/media/4066...9-greenock.pdf
    Last edited by Concerto; 04-12-19 at 15:48. Reason: Missing words
    If my foresight was as good as my hindsight, I would be a multi-millionaire.

  6. #36
    Join Date
    Dec 2005
    Location
    Far S. Cornwall
    Posts
    13,483

    Default Re: UK Tides Times

    Drift:
    Tides a mystery for one Greek chap. He is the goto fellow at Port Heli (daughter was babysitting Patna there this summer), as a much younger man he came to the UK and was in Plymouth, (at the Marine School I think). He told her he spent many days visiting the quay and taking measurements to try to get a handle on the tides....until someone introduced him to a tide table.

  7. #37
    Join Date
    Nov 2008
    Posts
    7,056

    Default Re: UK Tides Times

    Quote Originally Posted by Steveberry View Post
    Going back to the original premise: How to work out what the tides will be some weeks or months in advance, given that the free online sites usually only forecast 7 days ahead; can I offer what follows? If anyone thinks I’m miles off, then I’d welcome corrections:

    Step 1. Look ahead to the period that you are interested in, call it ‘Date X’. Find the moon phase on Date X - online sites do provide that sort of information many moons (boom boom) in advance. If your chosen date doesn’t fall exactly on full, new, half waxing or half waning, then applicate a number of days before or after one of those obvious moon phases.

    Step 2. Using the same moon phase site, look around your current date (minus 22.5 / plus 7 days) and find the date that has the same moon phase (or number of days before or after) as Date X; call this ‘Date Y’.

    Step 3. Go to your free online tide site and look at Date Y (note that although most free online sites only look forward 7 days, they do seem to go back about a month or so, though I’ve not looked into this depth). The tide times on Date Y will be very close to the tidal times on Date X. The tidal heights might be off because of the periodic variations in earth-lunar distance and earth-sun distance, but if it was (say) 3 days after Springs on Date Y, it will also be 3 days after Springs on Date X.

    Alternatively, go to your desired Date X in your diary and count backwards in 29.5 day chunks. When you get to a date that’s close to you (minus 22.5 / plus 7 days) note that as Date Y, click into your free online tide site on Date Y and you have the same result (and same caveats) as above. For obvious reasons this is much easier if you’re only forecasting a month or two in advance.

    Sorry about the noddy step-by-step description, but I couldn't find an eloquent piece of prose to describe how I do it! Shout me down if you think I’m wrong, but it’s a system that works for me. I’ve never taken the time to cross check against an Almanac at the planning stage, but I’ve also never pitched up and found the tides doing anything horribly unexpected…
    The older generation of Admiralty Charts used to give the time of "HW F&C" for major ports on each chart. That was the time of HW at the Full moon and New Moon, which is pretty constant. Moon phases can be predicted well into the future, and navigators would know. Reasonably accurate tide times can be estimated by interpolation.

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