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Author Topic: Dodd's proposed tunnel under the Thames  (Read 11342 times)

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Re: Dodd's proposed tunnel under the Thames
« Reply #9 on: February 07, 2013, 15:41:56 »
Background to the Planned Construction

As the Thames, and in particular the Pool of London, became increasingly congested with river traffic during the late 18th Century, various minds were turned to alternative means of crossing the Thames downstream of London Bridge. River traffic was becoming more and more congested and this was beginning to set a limit to trade. Docks had been built on the North bank of the river but goods going to companies south of the river had to be conveyed up-river, across London Bridge, where a toll had to be paid, then transported along the south bank to their final destination. This added time, cost and inconvenience - all of which were impediments to the expanding business of the British Empire at the peak of the Industrial Revolution.

In 1798 Ralph Dodd proposed the building of a tunnel between Gravesend and Tilbury to “The great and the good” of Kent and Essex - who he wanted to provide the funds to build it. There would also be military advantages in having a tunnel. It had long been recognized that there was a need to be able to move troops rapidly between Kent and Essex in the event of war - and where better to build the tunnel than near Tilbury Fort?

Ultimately this first known attempt to build a tunnel under the Thames, was a failure and I will explain what happened to it in later posts. 

Dodd’s Proposal

Dodd published his proposal in 1798. The attachment shows what Dodd imagined it would look like. The proposal is a very long and waffly affair and is lacking in technical detail - which is not surprising as Dodd had never built a tunnel in his life - though he did have first-hand knowledge of tunneling done by coal miners in the Newcastle area. The proposal seems to have been written to help potential investors to understand the scheme and get them to back it with private funds rather than to specify how it would really be built. The proposed construction was a circular tunnel lined with stone.

The tunnel would be approximately 900 yards in length and the average depth would be 145 Feet below sea level.

Critique by Charles Clarke

The proposal was of great interest to the military, but Charles Clarke of the Gravesend Ordnance Office was not impressed—in particular he believed that the tunnel design would not work as Dodd had not thought through the dimensions correctly, but also that the design was fundamentally flawed and sought to provide mathematical proof of this. He also challenged assumptions about the likely use of the tunnel and questioned Dodd’s experience and capabilities.

Approval of the Tunnel

Despite Clarke’s objections, and by eliciting the support of people in high places, a company to build the tunnel was set up and an Act of Parliament passed to approve its construction. (Stat. 39 GEO. III., c73)


  • Guest
Re: Dodd's proposed tunnel under the Thames
« Reply #8 on: February 05, 2013, 17:03:28 »
Ralph Dodd (1756-1822)

I researched Dodd's tunnel a few years ago as part of a project about Thames Crossings that I have not yet put online but thought members of the KHF might be interested. I will start with a short history of his career.

Dodd's family came from Berwick on Tweed and he was one of three brothers. He had some education in mechanics then studied portrait painting at the Royal Academy in London but in the early 1790s developed an interest in engineering.

In 1794 Dodd developed some kind of aid to digging canals which after a trial was never implemented - and this seems to have set the pattern for a great deal of the rest of his career in engineering - lots of ideas but few of them coming to fruition.

Canals,Ports and Harbours

He went on to make a number of proposals for work canals and harbours including:
  • 1794/5: Survey and proposal for a Newcastle-Carlisle-Maryport Canal
  • 1795: Proposals for schemes in Tees and Durham areas
  • 1796: Tynemouth Harbour proposal


Dodd’s attention next turned to tunnels.

  • The 1796 Tynemouth proposal included the suggestion of a tunnel between North and South Shields - probably inspired by local undersea mining activities, and was based on estimating parameters used for tunnel costings for the Grand Union Canal.
  • 1798: Dodd proposed construction of a tunnel from Gravesend to Tilbury. The tunnel was a failure due to flooding, poor management and finance issues.
  • 1798:  Proposal for a canal from near Gravesend to Strood. This became the Thames & Medway canal though it is not clear that Dodd was involved past the planning and approvals stage. Although this canal was closed, a tunnel forming part of the route, and for many years shared by the canal and railway, is now used by trains travelling between Gravesend and Strood.

More Canals, Ports and Harbours

  • 1799: Plan for canal between Croydon and Rotherhithe. Although Dodd was initially appointed as the engineer he was replaced by Rennie. This later became the Grand Surrey Canal and the Croydon Canal
  • 1800: Involved with the Mersey and Irwell navigation
  • 1802: Proposal for North London (London to Cambridge) - not executed
  • 1806: Brighton harbour proposal
  • 1810: Proposed link between Andover and Basingstoke canals - not executed
  • 1811: Grimsby harbour proposal
  • 1815: Continuation of Surrey Canal to Vauxhall - not executed


  • 1798: Proposal for replacement of London Bridge - not selected
  • 1800: Initial report about a possible bridge across the Mersey at Runcorn
  • 1806: Vauxhall Bridge - built but Dodd was again replaced by Rennie as engineer
  • 1808: Took out patent for bridge flooring but this was used very little in practice
  • 1814: Proposed  bridge from Ratcliff to Rotherhithe got as far as a trial span being built
  • 1820: Bridge built across The Fleet at Holborn but this had to be reinforced and had major defects reported by engineers Henry Maudsley and Bryan Donkin


  • 1804: Proposals for waterworks in SW and NE London - with follow up proposals for West Middlesex and Kent. The South London waterworks was actually completed and is one of Dodd's few successes. West  Middlesex, East London and Kent waterworks were all built but Dodd was replaced as engineer.
  • 1808: Proposals for waterworks in Birmingham, Portsmouth, Manchester and Colchester

Other Works

  • 1815 he issued “Practical Observations on the Dry Rot in Timber”.
  • Dodd was also a keen promoter of steam navigation

Concluding Remarks

Ralph Dodd was injured by the bursting of a steam vessel at Gloucester and died in Cheltenham in 1822.
He could easily be dismissed as a failure, and some of his schemes did in reality fail. He certainly seems to have had a flair for publicity and generating public interest, but was judged not to have the experience to see his ideas through to completion. Given his track record and lack of formal engineering training this is easy to understand. In this day and age, it is rather difficult to understand how somebody like him was taken seriously by investors. But thinking of recent events like the “dot-com” hype and subsequent collapse maybe we never learn!

It has to be acknowledged that a fair number of his schemes were eventually completed successfully by other people - though in improved versions and much later.

Personally I would not have let him build me a garage!

Offline kenty

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Re: Dodd's proposed tunnel under the Thames
« Reply #7 on: February 06, 2010, 18:45:28 »
Found this on the website:

"A Thames Tunnel was started some 800 yds. east of Tilbury Fort, to join Tilbury to Gravesend in 1798. Much difficulty was experienced with flooding so a steam driven pump was used. After a number of disasters the pumping was abandoned and a figure of £15,242.10s.4d. was expended on the project before the share holders called it a day. Not so much a tunnel but a well.
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Offline Riding With The Angels

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Re: Dodd's proposed tunnel under the Thames
« Reply #6 on: February 06, 2010, 18:41:50 »
I am making enquiries with a friend of mine who may be able to locate (if I ask nicely - read pester!) the items held by the Scottish library as I am now intrigued to know where the shaft and engine house were located.


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Re: Dodd's proposed tunnel under the Thames
« Reply #5 on: February 06, 2010, 15:29:29 »

      Thanks Merc and Riding with Angels,  all very interesting about the proposed tunnel.


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Re: Dodd's proposed tunnel under the Thames
« Reply #4 on: February 06, 2010, 13:46:56 »
From The Times

July 21, 1798

When the scheme ended Mr Dodd went on to work on the Thames and Medway Canal, but he left that project a few years later, before the Higham-Strood tunnel was built. Dodd, although a great Engineer and visionary, suffered  failures and took up drinking. He died in 1827, a broken man.

Offline Riding With The Angels

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Re: Dodd's proposed tunnel under the Thames
« Reply #3 on: February 06, 2010, 02:47:05 »
Found this link - relates to 1799 plan

pumping engines provided by Boulton Watt

The National Library of Scotland holds plans in file MS.19877

This link when searched 'gravesend' says

'Dodd's Gravesend Tunnel project was the earliest proposal to bore a passage beneath the Thames. It probably came about because of his previous svheme to dig a tunnel beneath the Tyne, which attracted considerable interest as the first underwater tunnel scheme. Dodd's plan and estimate for a 900 yards long and 16 feet in diameter passing 20 to 30 feet beneath the Thames, and a meeting in Gravesend Town hall to attract support.....This was persuasive enough to resuult in an Act in 1799 and a vertical shaft was sunk on the Gravesend side but there were problems with drainage and when the uninsured pummp house burnt down in 1802 the project came to an end.'


Deed of Bromley, and Gravesend Tunnel Act, 1678, 1799


Kent County Archives inventory title is: (U744) Deed of Bromley and Gravesend Tunnel Act
Contains detailed abstracts of land ownership in Bromley and a copy of the "act for making and maintaining a tunnel or road under the River Thames, from or near to the Town of Gravesend,... Kent, to or near to Tilbury Fort ... Essex."
IN Finding aids / Kent County Archives Office.

From Gravesham's website - ?30,000 was raised.


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Re: Dodd's proposed tunnel under the Thames
« Reply #2 on: February 05, 2010, 19:37:01 »

from Kentish  Gazette 30 March 1802 back page col.2
Tunnel under the Thames:
To Miners, Well-Diggers and others:
The company of proprietors hereby give notice that the Steam Engine being nearly ready for work, they will on 5th April next be prepared to contract with any proper person for sinking a shaft near Gravesend.  140-ft deep and 9-ft diameter, the company keeping the shaft sufficiently free from water.   Any person desirous of contracting for the same, may see the necessary particulars at Mr DODD?s (the engineer), at Gravesend;   or at his house No. 34 Parliament Street, Westminst
er;   or at Mr BENTLEY?s No.14 City Road.
    Proposals to be delivered in, sealed up, at the London Tavern, Bishopsgate Street, between 11 and 12 o?clock on 5th April next.


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Dodd's proposed tunnel under the Thames
« Reply #1 on: July 21, 2009, 20:27:34 »
In 1798 the builder and engineer Mr Ralf Dodd proposed to build a tunnel under the River Thames at Gravesend to connect to Tilbury,thus connecting Kent and Essex.
The tunnel was to be cylindrical and to be constructed wholly with key-stones,for greater strength.
Diameter of the tunnel would be 16 feet in the clear,to which Mr Dodd imagined would be sufficent for foot,horse,and carriage passangers.
The passage was to be illuminated with lamps and a steam engine was to be erected to draw off any drainage water.
Mr Dodd was of the opinion,that whether the project was considered as a great national improvement,or a local
 one to the two counties,or forming a military Passage of the first consequence in that part of the kingdom,for enabling troops to pass through,it's importance claims the greater attention.
Another question he suggested was,what may be the most proper method of rallying the supplies to defray the expence of the undertaking,Whether by the joint expence of both counties,or by a subscription of private individuals,incorporated by Parliament,with authority to levy tolls.
The latter mode,he was convinced,would be beneficial to the individuals,and amply repay the Shareholders.

However,Dodd failed to find enough capital to fund the tunnel and severe flooding in the part of the tunnel that was actually started,caused the ambitious undertaking to be abandoned,so Dodd turned his attention to his next project,the Thames and Medway Canal.


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