They both came out to South Australia aboard the Irene, and promptly set about installing the line from Adelaide to Port Adelaide and The Semaphore, replacing a less permanent privately operated line financed and constructed by James MacGeorge.
[1] Around the end of 1857, he was appointed assistant to Ben Hay Martindale ("Captain Martindale"),[2] Superintendent of Telegraphs in New South Wales, and on 26 January 1858 opened the telegraph line from Sydney to Liverpool, a distance of 22 mi (35 km).
[4] Cracknell was interested in military science, and prominent in promoting the shore defence of Sydney Harbour by means of torpedoes.
[5] Cracknell died after a heart attack, and was accorded a full military funeral before burial at Waverley Cemetery.
Cracknell married Margaret Cunningham in Rochester c. 1853;[7] they had three surviving daughters and one son: They had a home "Richmond" on Edgecliffe Road, Sydney His brother William John Cracknell (died 1 December 1898) was for many years Superintendent of Telegraphs in Queensland.