John I . Thornycroft & Company John I . Thornycroft & Company Limited , usually known simply as Thornycroft was a British shipbuilding firm started by John Isaac Thornycroft in the 19th century . History . The 16 - year - old Thornycroft , helped only by his younger sister , began to build his first small steam launch in 1859 in his father ' s back garden at Chiswick on the River Thames . He returned from an apprenticeship in Glasgow in 1864 and began to build more steam launches . Thornycroft first began shipbuilding at Church Wharf in Chiswick in 1866 , when the plot of land which became the nucleus of the shipyard was purchased . Here , the first instance was built of what would become the torpedo boat , the " Rap " for Norway in 1873 . This was followed by HMS " Lightning " for the Royal Navy in 1877 . In June 1904 the company decided to relocate to Woolston , Hampshire , where it acquired the shipyard owned there by Mordey , Carney & Company , and in 1908 they also set up the Hampton Launch Works on Platts Eyot , an island on the Thames at Hampton , Middlesex . The former yard at Chiswick closed in August 1909 . The first ship built by Thornycrofts for the Royal Navy at the Woolston Yard was the Tribal - class destroyer HMS " Tartar " . John Isaac Thornycroft died in June 1928 , but his role as chairman of the company had been taken by his son , John Edward Thornycroft in 1908 . Woolston built the ferry for Uganda in 1930 . She also survives , but as a half - submerged wreck on the shore of Lake Albert . Thornycroft continued to build civilian vessels . The Hampton Launch Works built yachts including " Enola " ( 1928 ) , " Estrellita " ( 1934 ) ( now called " Rake ' s Retreat " ) , " Aberdonia ( 1935 ) , " and " Moonyeen " ( 1937 ) . The pre - war motor yacht " Prunella " may also have been built at Hampton . These four have survived and are now recorded on National Historic Ships ' National Register . The first seaworthy Assault Landing Craft ( ALC ) , later renamed LCA , Landing Craft Assault , ordered built for the British Navy were by Thornycroft . The first prototype ALC No 1 was built by J . Samuel White of Cowes to a design by Fleming Jenkin , but it was not very successful . Thornycroft ' s design was much closer to what the navy wanted , with its low silhouette , silenced engines and shallow draught . Designated ALC No 2 , it was 41 ft 6 in long over all and driven by two Ford V8 engines of 65 bhp each . The design was slightly modified by the Admiralty and some 1 , 929 were built during the World War II . In 1944 sixty were being built each month . The LCA was reasonably seaworthy , so long as waves were less than 5 ft high . In heavy seas the situation could become critical and a number of LCAs converted to support craft disappeared in the choppy seas of D - Day , 6 June 1944 . In 1944 267 were lost ( out of 371 losses during the whole war ) . In 1955 , the company built " Scillonian " , a passenger ferry built for the Isles of Scilly Steamship Company . In July 1960 John Ward Thornycroft , John Edward Thornycroft ' s son , replaced his father as chairman of the company . In 1962 , John I . Thornycroft and Sons was building wooden yachts in Singapore . Thornycrofts merged in 1966 with Vosper & Co . , part of the David Brown Group , to form one organisation , although the formal merger to create Vosper Thornycroft took place in June 1970 . The company now trades as VT Group .