MM5AHO
Well-Known Member
Is it possible to determine a time of High water at a location from the moon meridian pass time (ignoring coastal effects on tide).
Determining tides without a tide table
- Thread starter MM5AHO
- Start date
lpdsn
Well-Known Member
Yes, use tidal constants to calculate HW time yourself. The Admiralty probably sell a set covering most ports, but I've never bothered searching them out myself.
You don't even need to ignore coastal effects as they're taken into consideration.
You don't even need to ignore coastal effects as they're taken into consideration.
MM5AHO
Well-Known Member
I'm actually wanting to calculate tidal flows for the Faroe Islands. I have a tidal atlas for there, but it seems to relate to Moon Mer Pass rather than a time related to a standard port. (UK tidal atlas shows tidal flows for a location related to HW Dover.)
lw395
Well-Known Member
Ignoring the coastal effects of tides would be to miss the point entirely
Tides are about 5 hours out of phase between Plymouth and Portsmouth, the coastal effects dominate.
ithet
Well-Known Member
You need a "Cotidal" chart. This gives lines of constant tide difference from moon overhead a set point (i.e. Greenwich).
https://www.researchgate.net/figure/15-Co-tidal-lines-for-M2-S2-the-major-tidal-constituents-in-the-North-Sea-Sager-1959_fig38_307586374
https://www.researchgate.net/figure/15-Co-tidal-lines-for-M2-S2-the-major-tidal-constituents-in-the-North-Sea-Sager-1959_fig38_307586374
johnalison
Well-Known Member
All you need to know is the Establishment of the Port.
lpdsn
Well-Known Member
Ah OK. I guess you first need to find out if it's the Greenwich meridian pass or local. Should be relatively easy to find the time of the moon's meridian pass after that.
I've always wanted to sail up to the Faroes, so will be interested in seeing your postings on the trip when you get there.
Edit: Here's an idea. Use the tidal atlas to make a prediction then compare it to Easytide to see if you're accurate
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NormanS
Well-Known Member
Old Admiralty charts used to give the time of Spring Tides for ports. It was called HWF&C (HW Full and Change), which is a constant, so provided that you knew or could see the stage of the Moon, you could get a pretty fair idea of the the time of the tide. Of course that was before the RYA expected you to calculate the time of tide to umpteen decimal places. 
LadyInBed
Well-Known Member
:encouragement:
For mid English Channel area:
Springs - HW Dover occurs at about Mid Day & Midnight
Neaps - LW Dover occurs at about Mid Day & Midnight
From HWD to LWD current flows West
From LWD to HWD current flows East
Slack water is at about HW & LW Dover.
eg:
Wed 06 March New Moon
High water 00:10 6.35m
High water 12:05 6.45m
Thu 14 March 1St Qtr
Low water 11:46 1.80m
Low water 00:07 1.95m (Fri 15)
Thu 21 Match Full Moon
High water 00:12 6.95m
High water 12:13 7.10m
Thu 28 March
Low water 12:05 1.95m
Low water 00:24 2.25m (Fri 29) Last Qtr
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Aja
Well-Known Member
Hope you are able to time your arrival with the tides :encouragement: we just had to plug our way north against two to three knots to Torshavn.
Torshavn
Wednesday, 06 Mar 2019 UT/GMT
▼ 01:50 -0.0m
▲ 06:15 0.4m
▼ 14:30 -0.1m
▲ 18:20 0.3m
▼ 22:00 0.1m
▲ 23:10 0.1m
Thursday, 07 Mar 2019 UT/GMT
▼ 02:20 -0.0m
▲ 06:40 0.4m
▼ 14:55 -0.0m
▲ 18:45 0.3m
▼ 22:30 0.1m
▲ 23:30 0.1m
Friday, 08 Mar 2019 UT/GMT
▼ 02:45 -0.0m
▲ 07:05 0.4m
▼ 15:15 -0.0m
▲ 19:05 0.3m
▼ 23:15 0.1m
▲ 23:35 0.1m
Saturday, 09 Mar 2019 UT/GMT
▼ 03:10 -0.0m
▲ 07:30 0.4m
▼ 15:40 -0.0m
▲ 19:30 0.3m
Sunday, 10 Mar 2019 UT/GMT
▼ 03:30 -0.0m
▲ 08:00 0.4m
▼ 16:00 0.0m
▲ 20:00 0.3m
Monday, 11 Mar 2019 UT/GMT
▼ 04:00 -0.0m
▲ 08:30 0.3m
▼ 16:20 0.1m
▲ 20:30 0.3m
Tuesday, 12 Mar 2019 UT/GMT
▼ 04:25 0.0m
▲ 09:10 0.3m
▼ 16:40 0.1m
▲ 21:10 0.3m
62º00'.0N 6º46'.0W
Torshavn
Pinched from the Imray Tidal atlas I used. Good luck with the multiple tides!
Donald
Minchsailor
Well-Known Member
A few years ago I was up in the Faroe Islands and Met Willy Ker who (at that time) was the editor Of the RCC pilot. Subsequently we had some correspondence on how to link the (incomprehensible) Faorese time tides to a Standard port (I seem to remember Reyjavik worked quite well). I no longer have access to all the emails, so no further information, but he was going to incorporate it into the newer editions of the pilot.
However, when I showed the tidal stream atlas (the 'Red Scare Book') to a couple lo local fishermen, they were flummoxed - so don't worry too much.
PS - It didn't help that in the year we went the Faroese Álmanakkinn (incidentally a wonderful book which has pictures of every fishing boat, and home telephone numbers of all the members of parliament, amongst other things) had incorrect tide table, and the correct one was in a supplement. As all this was explained in Faroese we hadn't a clue what was going on.
MM5AHO
Well-Known Member
That's interesting. I might look out for that book. As I can get by in Icelandic, Faroese isn't too different, so should manage that. (I moved to Scotland from Iceland in the early '90s)
Minchsailor
Well-Known Member
If you are visiting the Faroes there is book with plans of EVERY (about 70) harbour/pier/quay, with (probably) something on pilotage and facilities. It is all in Faroese so was complete double dutch to me, but worth it for the plans. More comprehensive than the RCC SDs.
It is "Havenoplysninger for Færøerne". Available from Jacobsens Bookstore in Torshaven. When we visited (and this was few years ago) they were quite happy to send the books to me here in the UK, on the promise we would pay for them when we arrived!. Possibly, by now they are bit more into e-commerce.
As a taster, here is the page for Vestmanna on Streymoy (a must visit place for the bird cliffs on the NW side).
MM5AHO
Well-Known Member
That looks as useful as CCC directions. I know that bookshop they do mail order ok. Will get one. Thanks
