The National Archives are putting together a searchable archive of people who were at the battle of Trafalgar.

http://www.nationalarchives.gov.uk/trafalgarancestors/

There are seven people listed as born in Caithness so far:

Daniel Clyne 32 Able Seaman
John Hogg 28 Yeoman of the Sheets
John Keay 22 Able Seaman
Alexander McBeth 22 Landsman
James Miller 22 Landsman
James Sutherland 23 Ordinary Seaman
Henry Taylor 35 Ordinary Seaman