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Discussion Starter · #1 ·
Hi

Has anyone ever seen any photos anywhere of the building of the Crosby Channel training walls, starting in 1909. Hopper ships were used to drop massive loads of limestone, though I presume they'd first dredge out some of the sand to make room for the wall.

thanks
 

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What are/were the Crosby Channel training walls ??
 

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The main channel from the Mersey Bar to Liverpool is the Crosby Channel, the training walls are walls of rubble on either side banks of the channel to stop the channel filling in with sand and mud
 

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Discussion Starter · #4 ·
More on the training walls

Here's some more detail about the training walls.

Crosby and Blundellsands beaches are an ideal grandstand to observe shipping, because the Crosby Channel, the only deep navigable exit of the Mersey Estuary, is barely a mile away. A big ship at that distance looks as if you could almost reach out and touch it. Few places elsewhere in UK provide such a close view of ocean-going vessels in an open sea location; only The Solent is even comparable. The channel runs north close to the coast as far as Blundellsands, then starts to swing west, from a point level with the site of the old coastguard house next door to Blundellsands House. The upstairs of Blundellsands House gave arguably the best close view of shipping on the Crosby coast, and was therefore also one of the best anywhere in the country.

By 1907, the usuability of the Channel was becoming a problem, with ever-larger liners unable to navigate through at low tide. A commission of experts recommended a solution to the Mersey Docks and Harbour Board, which solved the problem. The position and depth of the Crosby Channel are now maintained by underwater 'training walls' - banks of tipped limestone. Their main construction began in 1909 on the side of the Channel closest to Blundellsands on the edge of Taylor's Bank, so William and Edith would have seen and surely heard a succession of up to ten hopper ships dumping their 660-tonne cargo on top of the wall, using poles for alignment, to build up a triangular cross-section underwater wall, to hold the sandbank to a fixed position and increase scouring in the Channel. Limestone came from the Llandulas quarry in N Wales, loaded directly onto the hopper vessels at their adjacent jetty, still operational and visible from the A55. The work could only be carried out during a short window near high tide, and in calm weather. The work continued until 1960, with gaps during the wars. By then both sides of the Channel had been lined to an approximate five feet above mean sea level for a length of 15 miles, creating a greatly reduced need for dredging, and protecting the Channel from moving or breaking through into secondary channels through Taylor's or Burbo Banks. Random stones at the top of the walls can often be seen, peeping out of the edge of the sandbanks, when passing by ship on a low tide. But the enormous extent of underwater stone is hidden - these are massive structures, 7.5-10m wide at the top and up to 60m wide at the base, sloping out at 2:1, ie about 30 degrees from horizontal, and up to 20m high. Imagine what these would look like on land - a huge artificial valley as long as the distance from Liverpool Pier Head to Chester.
 

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The main channel from the Mersey Bar to Liverpool is the Crosby Channel, the training walls are walls of rubble on either side banks of the channel to stop the channel filling in with sand and mud
Olly
The seaward stretch of the channel from the Bar light to Crosby bend is named Queens Channel. The Bouys are Q1 to Q11, Then there is C1, Alpha and Beta on the port hand(inbound) and then C2 right up to C23 at the mouth of the Mersey.
There is a good history of the Channel training banks construction at this link.
http://www.engineering-timelines.com/scripts/engineeringItem.asp?id=788

regards,
Pat(Thumb)
 

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Me too, Pat, thanks for that. Living in Formby as a young lad I was familiar with Taylor's Bank and the revetment. Henderson's Pegu came up on it very early in the war and stood as a reminder to all navigators for many years. The Ionic Star was luckier; she missed it, being a bit too far North and coming right up on Formby Point's sandy shore.

When first introduced to computers, I found a site dealing with the subject of the changing sand formations at that part of the Crosby/Queens channels at different times. The latest recorded showed
Taylors Bank no longer separated from the shore but part of it. I must try and find that site again, if it still exists.
 

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Discussion Starter · #9 ·

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Me too, Pat, thanks for that. Living in Formby as a young lad I was familiar with Taylor's Bank and the revetment. Henderson's Pegu came up on it very early in the war and stood as a reminder to all navigators for many years. The Ionic Star was luckier; she missed it, being a bit too far North and coming right up on Formby Point's sandy shore.

When first introduced to computers, I found a site dealing with the subject of the changing sand formations at that part of the Crosby/Queens channels at different times. The latest recorded showed
Taylors Bank no longer separated from the shore but part of it. I must try and find that site again, if it still exists.
The attached map shows the situation in 2001, when the Formby channel seems to have disappeared, and Taylors Bank is conjoined with Mad Wharf Sands. But I suspect that the Formby Channel which was 15m deep is still in existence in a diminished state.
Regards,
Pat
 

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Thank you both for the charts of today's sandbanks. My boyhood memories of the Formby shoreline were different from what we see there now. We would lay so-called night lines, baited with big, black worms, along the channel that always separated Taylors Bank. This was done at low ebb and, we would return at the next one, sometimes only to find that crabs had eaten the best of the catch. Still, a few flukes were always welcome at home.
 

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Fascinating tread, thanks very much guys! I grew up in Hoylake and silting and the moving channels has always been a major issue. I watched a programme on tv recently that said the silting of the Mersey had been a problem from the earliest days (meaning 2-300 years ago) hence the building of the dock system, so Liverpool's success as a port was based on the ability to hold back the sands.
 

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The information given in this thread that in former times depths of 15 metres were to be found in both Formby Channel and the Rock Channel calls for some clarification and an answer to the question, "When was that?"

Every mariner knows that soundings shown on charts refer to soundings to be found at low water rather than at high water; and that the variation in the depth of water during the ebb and flow of any tide is of vital significance. In round and approximate terms, a variation of 10 metres or 30 feet in available depth during the course of a tide is commonplace in any six-hour period at Liverpool during spring tides.

I speak with no accuracy as to the available depth (or least depth) of water in Queens and Crosby Channel today, but during my own career it varied somewhere between approximately 24 and 26 feet (or about 8 metres) at low water, with a further 10 metres to be added to that figure on the top a large spring tide, thus a matter of about (and I stress the approximation)18 metres available at High Water spring tides.

For the reasons mentioned, it would seem that any figure of 15 metres available in Formby Channel or the Rock Channel at any time in history could only have been at High Water on a spring tide; and was therefore not a figure which could be relied upon for everyday navigation. (i.e. it was a maximum occasional and not a minimum reliable depth.) The very reason why soundings on charts are recorded and calculated as at low water is to give the mariner the most reliable information available.

The mariner then needs to know his onions as to precisely what the tide is doing and is expected to do next.

It can safely be said (and needs to be pointed out) that anybody expecting to find a navigable passage 15 metres deep in the approaches to Liverpool at low water today should prepare himself for a serious disappointment.
 

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Very many thanks, Pat.

That is precisely the information which I query. It does not address the vital matter of the time of tide.

The fact that both Formby Channel and the Rock Channel were both navigable for small vessels (and marked with buoyage) I do not challenge. I used the Rock Channel myself, often enough.

It is the expression "up to 15 metres" which is less than clear - and the verbiage itself suggests a maximum depth rather than a minimum depth. A maximum depth available might be of some academic interest but it is the minimum depth available which is of far greater concern in navigation.

A depth of 5 metres at Low Water in either Formby Channel or the Rock Channel, giving a navigable depth of 15 metres (in ball-park terms) at High Water seems quite feasible; but a minimum depth of 15 metres at low water in either of those two channels seems highly unlikely - particularly when, as explained, the equivalent minimum depth at low water in the main channel for many decades has been a mere 8 metres or so - and maintained even then only at enormous cost and effort.

If you can find authoritative information showing a least depth of 15 metres at low water in any of the approach channels to Liverpool, I should be most interested to hear it.

Repeated thanks.

PS If it is right that the Rock Channel or Formby Channel ever provided a least depth of 15 metres at Low water, at any stage in history, then it is perhaps ironic to point out that it is only in very recent years that ships drawing 15 metres have come into existence.
 

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So now I know something about the Crosby Channel training walls. I'd never heard of them before, and even the term Training is explained. Good stuff! :)
 
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