| | | | |
| William Edgar De Crackenthorpe Cookson R.N. | Explanation |
| |
| Date (from) | (Date to) | Personal |
| No personal data. |
| |
| Date | Rank |
| 25 May 1857 | Lieutenant |
| 4 August 1868 | Commander |
| 8 February 1884 | Retired Captain |
| |
| Date from | Date to | Service |
| 3 December 1866 | | Additional Lieutenant in Excellent, commanded by Arthur William Acland Hood, gunnery ship, Portsmouth |
| 17 March 1870 | | Commander (2ic) in Royal Adelaide, commanded by Trevenen Penrose Coode, Devonport, flag-ship of the Port Admiral |
| (May 1874) | 23 June 1876 | Commander in Peterel (until paying off at Plymouth), Pacific |