Frederick Le Grand was appointed surgeon to H.M.S. Volage in 1834.
He was appointed surgeon to H.M.S. Cyclops, Captain H.T. Austin, in the Mediterranean on 21 November 1839. H.M.S. Cyclops, a steamer, was built at Pembroke, of 300 horse power and 1106 tons. 235 officers and men and 25 marines were on board. C.D. Steel was employed as Assistant Surgeon. 
Frederick Le Grand was employed as Surgeon Superintendent on three convict ship voyages to Ausralia:
to NSW in 1849
Rodney to VDL in 1850
Marion to Fremantle in 1852
He kept a Medical Journal during the voyage of the Adelaide
to New South Wales dated 18 July 1849 to 10 January 1850.
He kept a Medical Journal from 18 July 1850 to 10th December 1850 during the voyage of the Rodney to Van Diemen's Land in 1850 -
From Dr. Le Grand, Surgeon-Superintendent of the Rodney : Hobart Town, 10th Dec. 1850. The conduct of the prisoners generally during the passage was remarkably good, and there has consequently been little punishment required. The ticket-of-leave of J. B. from the ' York' hulk was withheld in consequence of misconduct while in harbour. This was the only prisoner whose ticket was forfeited. From the Rev. J. K. Walpole, Chaplain and Religious Instructor of the Rodney : - Hobart Town, 1850. ;The prisoners and the guard having now left the ship, I have the honour to address you with reference to what has occurred on our passage out. ..... The prisoners, as a body, were tractable and respectful; individual exceptions to this remark, of course, there were; but the surgeon, by his vigilance and excellent and kind discipline, maintained things in a most comfortable condition. A convict from Portland kept all the school records, and superintended the men's school; he gave entire satisfaction, as did also the teachers, especially four men from Portland; the convicts, also, were orderly and industrious in school. There were two brothers especially, who conducted themselves in an exemplary manner) I could mention many more with approbation, were it not that I am prevented by the limits of a letter.
Rev. J.K. Walpole, Chaplain and Religious Instructor of the Rodney remarked later that the prisoners as a body, were tractable and respectful, although there were individual exceptions; but the surgeon, by his vigilance and excellent and kind discipline, maintained things in a most comfortable condition. A convict from Portland kept all the school records and superintended the men's school; he gave entire satisfaction, as did also the teachers, especially four men from Portland; the convicts were orderly and industrious in school. There were two brothers especially who conducted themselves in an exemplary manner.
Frederick Le Grand was employed as Surgeon Superintendent on the Marion to Fremantle in 1852 .
Staff Surgeon 1857
He was appointed Staff Surgeon at the Deptford Dockyard on 14 November 1857 
He was on the Navy List of 1864 of retired Deputy Inspectors General of Hospitals and Fleets. (1 November 1864)
Frederick Le Grand was included in the Medical Register List 1865 - Residence H.M. Dockyard, Deptford, Kent. Qualifications:
Fellow 1844, Royal College Surgeons Engl.
University and King's College, Aberdeen - The Degree of M.D. was conferred on the following gentlemen after Examination, on August 3rd - Frederick William Le Grand, Staff Surgeon R.N.,
Frederick Le Grand died at Deptford on 4 November 1874 -
The Will of Frederick William Le Grand formerly of H.M. Dockyard Deptford at Kent, but lately of 22 Manor road New Cross Deptford, retired Deputy Inspector-General of Hospitals and Fleets of Her Majesty's Navy who died 4 November 1874 at 22 Manor road was proved at the Principal Registry by Sarah Le Grand of 22 Manor road, widow. Effects valued under £1500.
 United Services Magazine
 Report on the Discipline and Management of the Convict Prisons. 1850 By Great Britain. Surveyor-General of Prisons
 The Navy List
 Medical Times and Gazette
11 August 1860
 Ancestry.com. England and Wales, National Probate Calendar (Index of Wills and Administrations), 1861-1941
 Inquirer, Perth 4 February 1852
 Haultain, C. (compiled), The New Navy List, 1840, p. 201