Isaac joined the Royal Navy on 16 April 1903 as a Boy 2nd Class and signed for 12 years continuous service on 22 January 1906, his eighteenth birthday.
He served in the following ships and shore establishments: HMS Caledonia, 16 April 1903-31 May 1904 (Boy 2nd Class, Boy 1st Class 18 November 1904); HMS Pembroke,1 June 1904-5 October 1904; HMS Berwick, 6 October 1904-12 March 1906 (Signalman, 2 January 1906); Pembroke I, 13 March 1906-20 July 1906; HMS Charybdis, 21 July 1906-2 September 1907; HMS Cressy, 23 September 1907-29 April 1907 (Ordinary Signalman 1 October 1907); Pembroke I, 30 April 1909-9 November 1909 (Signalman 1 November 1909); HMS Tyne, 10 November 1909-14 March 1910; HMS St George, 15 March 1910-28 February 1911; HMS (-), 1 March 1911-30 May 1911; (14 days Cells), HMS (-), 14 June 1911-16 June 1911; Pembroke I, 17 June 1911-7 August 1911; HMS Crescent, 8 August 1911-15 September 1911; HMS Pioneer, 16 September 1911-29 November 1912; HMS Pyramus, 30 November 1911-29 November 1912-14 July 1914; Pembroke I, 15 July 1914-6 September 1914; HMS Cormorant (Wear), 7 September 1914-28 February 1915; HMS Blenheim (wear), 1 March 1915-31 March 1916 (Leading Signaller, 20 July 1915); Pembroke, 1 April 1916-30 May 1916 and 4 August 1916-9 September 1916; HMS Royal Arthur, 10 September 1916-16 December 1916; Pembroke I, 17 December 1916-3 January 1917.
He was awarded the DSM for his part in operations in the Dardenelles on 18 March 1915 and the Clasp to the DSM the following year.
His service document was noted: ‘Invalided - hemoplegia.’ ['Total or partial paralysis of one side of the body that results from disease of or injury to the motor centres of the brain.'] He died on 3 July 1917, six months after he was invalided from the Royal Navy, and was buried in Newark-upon-Trent Cemetery, Nottinghamshire (grave ref. K.'U'.265).