Born in the North East of England, Ralph Dodd was the second son of Alexander Dodd, and had an aptitude for drawing along with his elder brother Robert Dodd (1748–1816). After receiving an education in mechanics, both Ralph and his brother Robert spent five and a half years at the Royal Academy schools practicing as a portrait painter. His older brother Robert is known for his maritime landscapes and works on the French Revolutionary Wars.
Dodd had two sons, Barrodall Robert Dodd (c.1780-1837) and George Dodd (c.1783-1827); who both became engineers and pioneers of steam power. His namesake, Ralph Dodd(s) (1792-1874) went on to become an engineer and mentor to locomotive engineers George Stephenson (1781-1848) and relative Isaac Dodds (1801-1882), founder of Isaac Dodds and Son.
He has been well documented as an innovator and registered a number of building patents, including British Patent No 3141 on 3 June 1801 for a building system that was over 150 years ahead of its time.
As a high-profile founder and promoter of engineering schemes, particularly in London, England, Dodd generally resigned his tender as engineer within one to two years of his projects receiving Parliamentary approval. Most of his schemes went on to be successfully completed by renowned engineers of the day, such as John Rennie and Robert Mylne. During his career, Ralph Dodd, was known for his flair for publicity and generating public interest, but has been portrayed by some of his detractors as a failure due to his general early departure from these companies despite repeated success.
In December 1821 he suffered severe burns when the boiler of the paddle steamer Sovereign (80 feet long, of the River Severn Steam Yacht Co, built by H. Turner, Stourport and registered on 30 Jan. 1822, British National Archives Registration No BT/107/168) exploded at Gloucester on her trial run. The damage sustained to the ship was so bad that she was broken up directly. Following the accident he took advice to go to Cheltenham for his health and, since he was nearly penniless, he walked there in the middle of winter. He died at Cheltenham on 11 April 1822.
Having been employed to undertake surveys of canals, coal mines, harbours and other civil engineering works of the late eighteenth century Dodd turned his attention to tunnels, proposing the first under water tunnel in the United Kingdom in 1796. The Tynemouth proposal was for a tunnel between North Shields and South Shields, which was inspired by local undersea mining activities in Wylam and Whitehaven and was based on estimating parameters used for tunnel costings for the Grand Junction Canal.