Service records can be found in many different sources held by The National Archives, the main one being ADM 196. There is a partial personal name card index for this series at The National Archives.

Confidential reports on officers who served during World War One, and who in some cases continued serving beyond World War Two, have also been added to ADM 196.

Navy lists can also be used to trace officers' careers. The National Archives holds them from 1782 to 1987.

Royal Navy: Officers' Service Records

Royal Navy: Officers' Service Records, First World War, and Confidential Reports, 1893-1943

Royal Navy: Pay and Pension Records: Commissioned Officers

You can search for records of those who served on the British side in the Battle of Trafalgar along with their service histories and any biographical details found.

Use Tracing Your Naval Ancestors by Bruno Pappalardo (TNA 2003) in order to explore naval records fully.