These records are held by The National Archives in record series ADM 337, and are arranged by division and service number.

If you do not have the service number, it is usually possible to find it in the World War One medal rolls which are held in ADM 171

Royal Naval Volunteer Reserve

World War One naval operational records may be helpful if you have the names of the ships or convoys.

First World War: Operational records, 1914-1919