Sir Eustace Henry William Tennyson d'Eyncourt, 1st Baronet (1 April 1868 – 1 February 1951) was a British naval architect and engineer. As Director of Naval Construction for the Royal Navy, 1912–1924, he was responsible for the design and construction of some of the most famous British warships. He was also chairman of the Landship Committee at the Admiralty, which was responsible for the design and production of the first military tanks to be used in warfare. Personal life D'Eyncourt was born in April 1868 at Hadley House, Barnet, Hertfordshire. He was the sixth child of Louis Charles Tennyson d'Eyncourt (1814–1896) and his wife Sophia Yates (d. 1900). Through his father, he was a cousin of Alfred, Lord Tennyson. He was educated at Charterhouse, then became an apprentice in naval architecture at the shipyard of Armstrong, Whitworth & Co. in Elswick. By 1898, he was employed as a naval architect in Govan, Glasgow. There he met Janet Burns (née Watson Finlay), a widow whom he married that same year. She had two children from her first marriage, Kingsley and Gwyneth; she and d'Eyncourt had a son, Gervais, and a daughter, Cecily. Janet Tennyson d'Eyncourt died in 1909 when accompanying her husband on a business trip to Buenos Aires. D'Eyncourt received a number of awards and honours: in 1913, elected to the Athenaeum; in 1921, elected a Fellow of the Royal Society; in 1930, created a baronet; and in 1946, elected a fellow of the Royal Society of Arts. He was succeeded in the baronetcy by his son Gervais (d. 1971). The writer Adam Nicolson is Eustace d'Eyncourt's great grandson. Career As an apprentice at Armstrong, Whitworth & Co., d'Eyncourt worked on the design of warships for the Austrian, Italian, Norwegian, Spanish, Portuguese, and Turkish governments. He joined the Fairfield Shipbuilding and Engineering Company of Govan in 1898, before returning to Armstrong, Whitworth & Co. in 1902. In 1904, he undertook consultancy work on the state of the Turkish navy which earned him the Order of the Medjidie, Third Class. In 1912, d'Eyncourt was appointed director of naval construction with the Royal Navy. He pioneered new forms of ship construction that helped provide protection from torpedo attack. On 20 February 1915, First Lord of the Admiralty Winston Churchill asked him to be Chairman of the Landship Committee, a group of Royal Naval Air Service officers and engineers assembled to design a