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....

[@davidculmer1520]

Agreed. Lovely chap and so happy to share his knowledge.

[@michaelgramaglia1183]

@@cellobob2358 Atomic 4 or is it repowered?

[@jonwilmot5331]

Thanks Tom. If the instructor on our course had been as straightforward as that i would have finished it and understood it.

[@terrydickinson7252]

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

[@quasimojo7399]

Cheers Tom. Clear and concise.

[@marcusscrafton535]

What a wonderfully informative video. Thank you Tom. It’s almost 20 years since I did my Dayskipper exam so this is great revision

[@zeilgenot]

Tom, Your videos and also this one, is like reading a good book. Spot on and a very good read! Thnx, Harry

[@leeinnes7127]

I will happily listen to Tom talk about anything

[@paulputnam2305]

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

[@davidraper9629]

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

[@wimclinckspoor5731]

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

[@darthkek1953]

To nobody's great delight from now on I'm calling them Witch tides and Dead tides.

[@ianrobinson6788]

May be but it is also suggested that it comes the Old English word "springan" meaning to well up.

[@AA-4cx250b]

It’s not just your opinion, it’s how it is!

[@nickwebb9290]

You always explain things so well Tom, this video was no exception 👍

[@davidallen9526]

Good day Tom It's 0600 here in St. Louis Missouri USA. I must congratulate you for making these videos and providing detailed information in a way that any novice sailor can easily understand. I thank you for this. I enjoy your videos very much. Have a wonderful week Sir!

[@TomCunliffeYachtsandYarns]

Thanks David. You have a good week too. Tom

[@NauticalSimulation]

Thanks, Tom, for your many wonderfully useful videos 😊

[@grahamsmith8122]

I'm looking forward to using this knowledge when I'm next out on Rutland Water.

[@tadzixon6529]

Hi Tom! Pure joy to watch it:-) Thanks to your videos and books I passed my RYA Yachtmaster exam last year, so thank You Sir! I am a fan of the way You explain things. Greetings from the Polish coast.

[@TomCunliffeYachtsandYarns]

Always good to hear from our friends in Poland. I'll hope to meet with some of you guys this summer in Sweden.

[@PaulBKal]

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

[@stufirewalker]

Brilliant, as ever. Thanks Tom.

[@carl_sarg3870]

Excellent video, very well explained. You have yourself a new subscriber. Thank you very much.

[@TomCunliffeYachtsandYarns]

Welcome aboard!

[@HansUwe-y8c]

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

[@joesmith1142]

Great stuff, thank you Tom.

[@vwmovies]

Hi Tom, I am (hopefully correctly!) informed by ChatGPT that "The term “spring tide” originates from the Old English word “springan,” which means “to leap” or “to rise.” and - "The term “neap tide” comes from the Old English word “nepflod” (later shortened to “neap”), which roughly means “without the power” or “lacking strength.” Wonderful videos, many thanks.

[@sunlovesailing]

Excellent, thank you Tom!

[@ArturZagaj-Izraelita]

14:30 jak wyglądają przypływy np w Mikronezji? Czy małe bezludne atole powiększają się pięciokrotnie?

[@RobertMatichak]

Great explanation Cheers!!

[@reloadncharge9907]

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

[@SAILBOATJACARANDA]

Cheers Tom

[@PetervanGinneken]

I think the term spring tide probably comes from Dutch. In Dutch spring means jump so a jumping tide. As a sailing instructor in the Netherlands with quite a few German and English speaking students I have noticed that a lot of sailing jargon is really similar in Dutch German and English.

[@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

[@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

[@terrulian]

Yes, Tom, here in the US we use MLLW instead of LAT. This is based on empirical measurement over a period of 19 years, which is called a "tidal epoch." As it is empirical, I'm not sure why it's problematic, and I don't find it complicated, but I'd be very interested to hear your explanation for why you find it so. I'm a bit of an Anglophile and do love British nautical terms and traditions, but I never ran into this issue on a circumnavigation as we used US charts instead of Admiralty charts, and am a bit abashed to learn of it.

[@NeilLambden]

I like the French approach where the tables give a tidal coefficient as well as height so you know just how big the tide is compared with a standard tide, ie 1.2 is a very large spring, 1.0 a “standard” spring. You can then use these with currents too to give a tidal rate more accurately and easily

[@TomCunliffeYachtsandYarns]

Thanks for this. The French 'coefficient' method works really well. It's different from the UK but equally effective. As you say, the system is particularly useful for tidal streams.

[@63melvyn]

Brilliant

[@stephenwebb9167]

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

[@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.

[@patrickwalsh6873]

Since you're in a non-shaded area, should you not have added the hour to the tidal curve chart to make it a HW time of 1125 ?

[@TomCunliffeYachtsandYarns]

Good point, and thanks for raising it. I should perhaps have done so myself! But the answer is No. Times are worked in GMT or Zone time. You do your calculations then add the hour to the answer at the end. It can make a difference, especially with secondary ports. See next week!

[@patrickwalsh6873]

@@TomCunliffeYachtsandYarns Many thanks for taking the time to reply, it's appreciated. I should have mentioned that I'm a mere novice, studying for my Day Skipper. Which is how I happened upon your video. Looking forward to next week's video, cheers.

[@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...

[@sailingmrnice]

I grew up on the Bristol Channel. We got Spring Tides of over 18metres! That's a big tide!

[@TomCunliffeYachtsandYarns]

My cruising boat of fifteen years was a Bristol Channel pilot cutter built 1911 to operate in those waters with no engine. What seamen they were!

[@sailingmrnice]

@ I'm rebuilding a 1984 38' Endurance ketch!

[@timseytiger9280]

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

[@TAZAR_II]

It's a 'spring' like a mechanical spring.

[@ArturZagaj-Izraelita]

Uważam że natychmiast powinna ruszyć budowa co najmniej dwóch konkurencyjnych do Panamskiego kanałów. Rynek wymaga konkurencji. Korporacje też powinny zostać zniszczone- zlikwidowane.

[@SuperDirk1965]

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

[@darthkek1953]

Yacht...

[@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.

[@freakent]

I’ve experienced -ve tidal heights in Poole Harbour.

[@TomCunliffeYachtsandYarns]

@@SpiralDiving Thanks for this. I wrote the US Sailing text book on navigation a few years ago and recall well having to grapple with MLLW etc. I do think our arrangement in the UK and that of the French are both a lot easier to use. Tide gauges are always interesting. One has to be sure whether they are reading tide height or depth over some obstacle like a lock sill. Good luck with yours. What a lulu!