Tidal heights 1

[@cellobob2358]

I'm the first comment! I will use this opportunity to thank you, Tom, for all the wonderful education that you've given the maritime world! When I got my first big boat, a Tartan 30, the previous owner included one of your books to get me started. I've re-read it many times...

[@TomCunliffeYachtsandYarns]

It's good of you to say so. Sometimes we writers feel we're living in a sort of vacuum. Fair winds to you mate! Tom

[@michaelgramaglia1183]

Agreed! And it's not just because I too have a Tartan 30 (1976). Tom has been both fascinating and inspirational.

[@cellobob2358]

@ Ours is 1978....

[@terrydickinson7252]

Took my Dayskipper a couple of years ago in Portugal where little tide to worry about. Very clear explanation.

[@leeinnes7127]

I will happily listen to Tom talk about anything

[@paulputnam2305]

Thank you Tom for sharing this very informative data with us.

[@NauticalSimulation]

Thanks, Tom, for your many wonderfully useful videos 😊

[@PaulBKal]

Thanks Tom. Simplest explanation of tides I’ve ever seen. Everyone else always complicates it to billy oh!

[@davidraper9629]

Great lesson Tom. I'll share it with my youngest crew man. He's very enthusiastic about learning to sail this summer.

[@stufirewalker]

Brilliant, as ever. Thanks Tom.

[@HansUwe-y8c]

Thank you Tom, great explanation of the tidal secret, very helpful for me

[@reloadncharge9907]

Well done, a good video/ refresher! Thank you, Andrew, Florida

[@michaellippmann4474]

Fantastic explanation Tom...much of it is academic for me as most of my sailing takes place on the great lakes in North America but I have always tried to learn more about navigation. You are correct about most tidal ranges in NA however east coast of Canada experiences some very large tides. West coast as well but not to quite the same extent. Fascinating topic. On Lake Erie where I live we clearly do not have tides we do however have to deal "seiches" (spelling could be incorrect) which are wind driven tidal ranges, we can see a lowering of water levels at our end of the lake by as much as 5 feet (western basin) with a steady west wind, or vice versa for an east wind. These occur mainly end or beginning of the sailing season but we have experienced drops of several feet of water in a matter of hours. No tide tables for that! 😁 Anyway...Thank you for your videos! Mike and Ally S/V Bears Mistress II 🇨🇦

[@TomCunliffeYachtsandYarns]

Hi Bears MIstress. Very interesting. The same thing happens in my home waters in Denmark where wind-driven surges can reach well over four feet. The place is generally shallow and there can be some nasty surprises! Fair winds out there! Tom

[@2squiffy]

Tom another wonderful video thank you. I just wonder you didn’t add the hour. Any reason why not?

[@TomCunliffeYachtsandYarns]

Hi Squiffy. Yes. The trick is to do all the sums then add the hour to the final answer. When it comes to secondary ports it does make a small difference. Good point though. Cheers Tom

[@gurglejug627]

Hi Tom, I asked a year or so ago if you'd consider making a video of changing sails at sea / in the wind and waves and IIRC your reaction was rather positive, so just a polite reminder - if you get time... it's the only facet of sailing where I personally muddle through and don't plan to well in terms of analysed, logical steps, and guidance would really be appreciated. With hearty thanks for your videos.

[@TomCunliffeYachtsandYarns]

Hi I'll do my best this summer when I'm on board! Cheers Tom

[@wimclinckspoor5731]

In my opinion springtide has nothing to do with spring, but it comes from the dutch word spring, witch mean jumping or high. So one of the many maritime words that comes from the dutch sailing history.

[@marievictoire1939]

Astronomical tide tables give the tidal variations caused by astronomical factors only (nothing to do with extremes). They are at a fixed barometric pressure of 1013 millibars or 10 hectopascals. An increase of 32 will lower levels by .32 meters so very high or low pressure could be significant in your example. My boat draws 2m in Newport in Clew bay On February 9 1988 she was on the hard the tide should have been half way up her keel she floated for 6 hours the lowest pressure was 944 the hurricane force winds and the bay outside would also be factors. At midday she finally stopped moving and I could leave her, wet and cold I went to my local and ordered a hot whiskey but there was no “lectricity “ so I had it cold. Luckily it wasn’t a spring tide as I reckon it was a 1.3 m above astronomical level.

[@TomCunliffeYachtsandYarns]

You'll hear all about this in the next video or two! Thanks for making the point now though.

[@timseytiger9280]

Spring is not so bad, just think of an actual spring. Springing up and down like crazy. 😉

[@stephenwebb9167]

Gee, almost seems like someone designed it all to work perfectly. Thanks Tom

[@Cyrusmagi]

Did you get that old fishing smack that was lying at Brora in Sutherland in 2006 as i told a friend of yours about it ?

[@TomCunliffeYachtsandYarns]

No I didn't. I don't recall being told but it's a long time ago. I wonder what she was...

[@SuperDirk1965]

I guess the name "spring" comes from the Dutch word for jump which is spring. Not unlike many nautical terms in English.

[@sickgit66]

Another nicely done video Tom, one thing I've noticed that's not here is why sometimes we get negative tidal predictions, below the datum line, I've seen them a few times. I've googled it before and come back none the wiser?!? Any chance of an definite explanation?

[@TomCunliffeYachtsandYarns]

It can happen but it's very rare in the UK where I do my tidal operations. I'm unsure of the rationale behind it, but the LAT datum that's set is good for 99.9% of the time, so maybe it's best to leave it like that and note carefully when a negative figure does arise. I know it happens more often in the US where things are done rather differently.

[@SpiralDiving]

@@TomCunliffeYachtsandYarns In the US they use mean lower low water (MLLW) which is higher than LAT so negative numbers just mean you are closer to LAT on that day. For a negative number to appear on a LAT referenced table, something must have happened to the calibration of the local tide gauge (whose LAT is averaged over 19 years I think) so that to keep the chart datum depths correct a negative number needs to be inserted into the table. I'm guessing that heave or subsidence of the land on which the gauge sits could alter the calibration... YMMV of course.