Tide calculation?

[Akestor]

Hello,
I am studying tide calculations manually, such as tide tables and curves. However, I am sailing in the Mediterranean, where there is no tide, so I have no actual experience. I was wondering what apps you use to plan a daily trip for example in the Solent which is so popular. I assume no one bothers making this on paper nowadays

 

[Caladh]

It’ll be worth genning up on Solent tides as there are “stands” in various locations and tidal calculation are based on low tides rather than high.

 

[oldmanofthehills]

Its currents one needs around UK and they can lag tide by up to 4 hours

UK maps have current direction tables for various points and pilot books have tidal flow maps

Solent is complex as tidal currents bounce off the isle of wight giving an intermediate high tide and low tide

Modern chart plotters also show current though mostly once one knows an area one just remembers the flow relative to low or high tide

 

[Stemar]

Pretty much any of the tide apps will give you an idea, but I, and many others, like Absolute Tides. It'll cost you a bit for the tide data, but it's reliable, though I wouldn't take the graphs as exact truth.

One of the interesting things about the Solent is that the current in the eastern Solent turns a couple of hours before HW and LW as the hump of HW moves up the channel and flows round the Isle of Wight and in from the east, and the opposite for LW

If you really want to frighten yourself, look at the tides and currents for the Bay of Fundy.

 

[wrr]

Have a look at the ABP website for a taste of the complexities in the Solent: Southampton Tides
Having made some exact calculations, then note that weather conditions can lead to tides over 1m greater than predicted such as Sunday 20th October when the high tide at Gins Farm was 1.1m above predicted high water.

 

[Kwik Decision]

As others have said, the tidal currents are every bit as important as the tidal heights in areas like the Solent. I go for an inherently simple way of working these, and have laminated the tidal stream pages from an old almanac (double sided A4 sized, so there is only 1 thing to have to hand). I then look up high water Portsmouth for the day in question (either on line, or use the current almanac), and write on the times with a dry wipe pen. As a very rough rule of thumb, the W'ly stream starts 1 hr before HW Portsmouth, and the E'ly stream 6 hrs later.

 

[Sandy]

I use paper all the time.

Easy to use, easy to share with crew.

 

[capnsensible]

The Admiralty tide stream atlases are inexpensive and hard to beat.

 

[Sandy]

The Admiralty tide stream atlases are inexpensive and hard to beat.

and never go out of date.

 

[dansaskip]

I don't use apps for this but do use paper - it is not outdated yet. I use a tidal stream atlas, the Admiralty do good ones for the different areas and the like Kwik Decision I write the times for each hour of the tide on the atlas. Only differ from him in that I write on with a very soft pencil which is easy to rub out with the correct eraser. But the idea to use a laminated one and a dry wipe pen is a very good idea.

 

[Sandy]

Another good book is:

The Yachtsman's Tidal Atlas: Channel Ports & Approaches

 

[capnsensible]

And reeves-fowkes for the channel. I used to use that a lot when my access to Admiralty publications ended.

 

[Babylon]

Throw your apps away...

For the Solent I just use this double-side laminated version together with tide times from KHM Portsmouth and I have a similar one laminated for the Channel (Dover tides). Also have the full Admiralty ones on board (larger scale, one full page per hour of tides) but only use these for planning longer coastal or offshore passages.

Further afield, any given almanac (e.g. Cruising Association or Reeds) will give tidal stream chartlets for all main areas, and curves etc for each primary port and tables to adjust times and heights for secondary ones.

Once you've done a few proper tidal height calculations, first in the classroom and then out on the water, the logic and mechanics are absorbed, then a quick look at the day's tide times and heights of HW and LW is usually sufficient to plan your passage and your anchorage etc.

 

[dunedin]

Hello,
I am studying tide calculations manually, such as tide tables and curves. However, I am sailing in the Mediterranean, where there is no tide, so I have no actual experience. I was wondering what apps you use to plan a daily trip for example in the Solent which is so popular. I assume no one bothers making this on paper nowadays

Hi

Whilst I use an app on my phone to determine tide times and heights (eg when is local high and low water), I think it is importantly to create a mental picture of when the tide flows in one direction versus the other, and roughly at what speeds - eg when the flow changes from running E to running W, and what the peak speed will be.
Use of a tidal atlas - which may be on paper or in a digital image form - is a good start for that.
Personally I wouldn’t just rely on an app or automatic routing, as I want to understand what is happening and make my own plans accordingly - eg
- if tides are relatively weak I will not worry too much about ideal departure times, as not too critical to progress
- if strong tides and rough waters, it can be very uncomfortable or even dangerous to go with the strongest favourable tide stream - if creates steep wind over tide waves. It may be better to go against a slight counter current, or at slack water, even if a bit slower

 

[B27]

Many racing yachtsmen will have a fair idea in their heads about when the tide turns at key places.
But the detail can be variable from one tide to the next, and the published data is only a guide.

There are several sources of data.
Charts
Admiralty tide stream atlases
Almanac
Various pilot books and guides.

From what I've seen of apps, a lot of them are quite dubious when you zoom in too far!

 

[finestgreen]

The Admiralty tide stream atlases are inexpensive and hard to beat.

If you do prefer screens to paper though, the Imray Tides app will give you the same for a small additional fee, with the added advantage you can directly look at the date/time you're interested in.

 

[blush2]

A tidal atlas usually shows back eddies as which can be very handy when the tide is against you.

If you sail in the Solent there is a Peter Bruce book giving lots of info about eddies, tide races etc.

Other sources include harbour websites and pilot guides. For example HW or LW in the Dart happens some time before slack water outside the river.

 

[The Q]

If any of you are coming to the Norfolk broads, then this is a good site.
Norfolk-Broads.org Tide Table

 

[davidej]

I would just get Navionics on my tablet then I would be able to see tidal height and currents in my chosen cruising area for any future date and time I wanted.

Yes I did do all that manually for my Yachtmaster exam but thing have moved on a bit since Nelson’ s time.

 

[AntarcticPilot]

Perhaps worth noting that the uncertainties in tides caused by meteorological conditions can make a difference of a metre or more in height of tide, strength of tidal stream and timing of high water and slack water (which don't necessarily coincide). The Solent, which others have mentioned is notoriously complex and simple tidal calculations don't work! The Admiralty tidal atlases are an excellent and generally reliable resource, though they have insufficient detail in areas such as the Dorus Mor, where local knowledge is useful.