Tidal thames - where to get tidal stream information?

[Wjj]

I'm looking for tidal stream information for the tideway, specifically predictions of how fast the tide will flowing (in knots) at a given place at a given time. I can find high tide/low tide information easy enough and there are tidal stream charts for the estuary itself in Reeds Almanac, but I can't find anything for the tideway through London. Does anyone know a good source of this - either predictions for a specific day or general information, e.g. "half way through a falling tide the stream will be around x knots at tower bridge on a spring tide and y on a neap". I know these things vary a lot but I'm interested to know whether a 'fast' tide by local standards is is e.g. 3 knots or 8 knots

 

[RivalRedwing]

are there no tidal diamonds on the chart?

Tidal diamond - Wikipedia

 

[Boathook]

I would have thought that any figures, if any, could vary a lot depending upon how much rain has fallen in the Thames catchment area. There is possibly a delay between rain falling and effecting the tideway but how many days ?

 

[oldgit]

Ebb tide flag warning

On our frequent excursions up the Thames, we normally will factor in at least a couple of knots of tide to assist our passage , depending on Springs or Neaps.
We normally start off around Southend at LW, by the time we get to Gravesend we will have the benefit of 2-3 knots of flood.
This can increase, especially through those Central London bridges.

 

[Wjj]

Ebb tide flag warning

On our frequent excursions up the Thames, we normally will factor in at least a couple of knots of tide to assist our passage , depending on Springs or Neaps.
We normally start off around Southend at LW, by the time we get to Gravesend we will have the benefit of 2-3 knots of flood.
This can increase, especially through those Central London bridges.

This is one thing that's confusing me, at Limehouse it seems to run at 2-3 knots at springs (based on the difference in speed from doing a u-turn) - which is plenty fast enough for me - but in various places I've seen a claim that the tide runs at 8-10 knots. I understand it varies depending on rainfall and lunar things but this seems like a massive discrepacy.

Also looking at the graphs of tide height it seems that the actual flow is closer to a triangle shape than a sine wave, meaning that the tide gets up to nearly full speed relatively quickly and doesn't vary that much until it's nearly all the way in/out, but it'd be good to see what that means in knots.

 

[Wjj]

I would have thought that any figures, if any, could vary a lot depending upon how much rain has fallen in the Thames catchment area. There is possibly a delay between rain falling and effecting the tideway but how many days ?

that's an interesting point. The amount of water coming in with the tide is huge though, as well as the flow from upriver. Presumably out in the estuary the tide is the bigger effect and just below Teddington after weeks of rain the flow is the bigger effect, but where it tips over in the middle must be harder to pinpoint

 

[dunedin]

This is one thing that's confusing me, at Limehouse it seems to run at 2-3 knots at springs (based on the difference in speed from doing a u-turn) - which is plenty fast enough for me - but in various places I've seen a claim that the tide runs at 8-10 knots. I understand it varies depending on rainfall and lunar things but this seems like a massive discrepacy.

Also looking at the graphs of tide height it seems that the actual flow is closer to a triangle shape than a sine wave, meaning that the tide gets up to nearly full speed relatively quickly and doesn't vary that much until it's nearly all the way in/out, but it'd be good to see what that means in knots.

I have no specific knowledge of the Thames but would seriously doubt your 8-10 knots figure, unless you can find a credible source.
That would be up there with with the Pentland Firth and Corryvreckan in terms of the UK's fastest tide flows. And never heard the Thames ever mentioned in terms of these extremes. Even amongst rivers I didn't think the Thames was particularly exceptionally fast - eg compared to Severn, Tay etc - but may be wrong.

 

[Wjj]

are there no tidal diamonds on the chart?

Tidal diamond - Wikipedia

I have no specific knowledge of the Thames but would seriously doubt your 8-10 knots figure, unless you can find a credible source.
That would be up there with with the Pentland Firth and Corryvreckan in terms of the UK's fastest tide flows. And never heard the Thames ever mentioned in terms of these extremes. Even amongst rivers I didn't think the Thames was particularly exceptionally fast - eg compared to Severn, Tay etc - but may be wrong.

Yeah this is what's confusing me too, the 8-10 knot claim is in this article: Ebb and Flow – Ebb & Flow but I've heard it before I'm sure. I think it might be one of those numbers that just gets passed around. Perhaps it's up against bridge piers or something. What I can't find anywhere is some more specific data about the tidal streams. I've had a look at digital charts and can't find any information (openCPN/Ocharts on the laptop and raymarine charts on the plotter on the boat), I'll have a look at the paper chart (imray) when I get a chance to see if there are any tidal diamonds up the river. While it's not the pentland firth the Thames is fast enough that you have to think ahead!

 

[Outinthedinghy]

I've been through the pool on various small Boats and never seen the tide move anywhere near 8 knots. 5 maximum and I don't think it was even that. More like 2 or 3.

One situation when it is very fast further up around Richmond is if there is extra land water coming off the non tidal part of the River. As mentioned above this is also called fluvial flow.

At the end of March I moved a Boat from Limehouse to Teddington but there was so much fluvial flow that the inward tide movement effect was negated above Hammersmith. I used Hurlingham yacht club buoys (with permission) as a waiting area and punched up to Teddington on the next daylight incoming tide.

Although the tide was coming up the water was still flowing out. Richmond half tide barrier was open continuously.

I imagine when that tide turned it would have been extremely swift through Richmond. Maybe even as fast as the 8 knots but I'm not convinced. This might be where the high figures come from.