Go back to article: Engineering and the family in business: Blanche Coules Thornycroft, naval architecture and engineering design
The origins of ship testing in Britain
The move from empirical rule of thumb and ‘sailors know best’ methods to the scientific testing of the design of vessels was critical for the development of complex vessels.
William Froude became the recognised authority in the field (Handford, 2017, pp 26–28). Dartmouth born Froude graduated in Mathematics from Oriel College, Oxford in 1832. He worked for the civil engineer Henry Palmer and later for Isambard Kingdom Brunel. In 1846 Froude returned home and began to develop his theories about the movement of ships in water, using his own models on the River Dart and instruments he had built himself. In 1856 Brunel asked him to work on the stability of the sailing steamship the SS Great Eastern, at the time of her launch in 1858 the largest ship ever built (Leggett, 2015, p 175). Following the death of his father in 1859, Froude moved to Paignton in Devon, and, deprived of the river Dart, built a model boat testing tank in his attic. The boats were towed along the long narrow tank by means of a rope, which passed through a hole in the wall, and had a heavy weight on its end which descended outside the building. John Isaac Thornycroft later used a similar technique.
In 1867 Froude moved to Chelston Cross Hall, Torquay and built a second tank, this time at ground level. Froude’s work was beginning to gain influence and he persuaded the Admiralty to grant him £2,000 in 1868 to construct a third tank 278 feet long, 34 feet deep and 10 feet wide having an overall roof and a railway mounted gantry spanning the tank which allowed the movement of the models to be controlled (Leggett, 2015, pp 177–8).
© Imperial War Museum
The First Naval Testing Tank at Chelston Cross Hall. The image shows the overall roof and a railway mounted gantry spanning the tank, which allowed the movement of the models to be controlled
Known as the Admiralty Experimental Works, the tank opened in May 1872, and was the first official Admiralty testing tank. It remained in Torquay for seven years while William and son Robert Edmund Froude undertook tests on every Naval ship launched, using models. The Admiralty Experimental Works was then moved to Haslar, Gosport, with Robert as Superintendent in 1886.
HMS Captain, the first of the Navy’s new heavily armoured, but dual steam and sail-powered ‘turret ships’, was argued over in private and public. William Froude and other Institute of Naval Architects members, who had been advocating a scientific appraisal of new designs were worried that the ship was not stable. When HMS Captain was lost off the coast of Spain on 7 September 1870, with only eighteen survivors, some naval architects began to investigate design in more detail.
The Admiralty was prompted to form the Committee of Designs in January 1871, which was as Don Leggett notes: ‘…charged with investigating the Admiralty’s previous warship designs and its future construction policy’ (Leggett, 2015, p 170). Froude, senior naval officers, three commercial shipbuilders and other technical figures were all committee members. However, the ship launched in the first year of the Committee’s existence, HMS Devastation, though tested in model form by Froude and bereft of sails and rigging was such an unfamiliar shape that the public, Parliament and the news media were drawn into the discussion of whether it was safe. The debate raged for three years and Froude recognised that a public demonstration of her seaworthiness was necessary. Hence in 1874 he was allowed to simulate his model experiments with the full-scale vessel off Gibraltar. Froude achieved this by getting four hundred men to run from side to side of the deck showing that the ship safely rolled to the degree that he had calculated on the model (Leggett, 2015, p 187). The battles over the growth of scientific testing in naval architecture were not over but the process of change had begun.
Commercial shipbuilders followed Froude’s methods. In 1883 William Denny & Brothers of Dumbarton built an experimental tank in their shipyard based on Froude’s Torquay design and had a Scientific Department by 1892 (Mckenna and Ferreiro, 2013, pp 105–128). Sir John I Thornycroft began his ‘Lily Pond Experiments’ in 1904, (see below) and built his Bembridge Test Tank in 1910/11 (see below). The archival records used for this paper include correspondence between Sir John and Robert Froude. Others followed suit: for example, Sir Alfred Yarrow gave £20,000 to build the ‘Froude Tank’ at the National Physical Laboratory (NPL), Teddington, which opened on 5 July 1911. The archival evidence suggests that the Thornycroft tank was used only by the family business rather than testing ships for any other company. However, the NPL facility was able to undertake ‘investigations commissioned by shipbuilders, ship owners and other external organisations; plus the Division’s own programme of research’ (Anon, 2011, see this link). Blanche’s role was to help her father conduct the experiments and interpret the data captured from the tank. It is to her we now turn.
Component DOI: http://dx.doi.org/10.15180/1851009/003