HMS Sardonyx was an S-class destroyer that served with the Royal Navy in the Second World War. The S class were a development of the R class created during the First World War as a cheaper alternative to the V and W class. Launched in 1919 soon after the armistice, the ship was commissioned into the Reserve Fleet. Later that year, the destroyer was sent to Latvia, arriving just after the cessation of that country's war of independence. The ship took part in radar trials in 1939, and was upgraded shortly after the start of the Second World War with greater anti-aircraft and anti-submarine capabilities. The destroyer then served as an escort, usually for convoys of merchant ships. The ship was part of the 5th Escort Group which destroyed the German submarines U-99 and U-100, although Sardony