Dewar's best man was the Honourable Reginald Plunkett, who later became known as Reginald Plunkett-Ernle-Erle-Drax, and would go on to achieve high rank in the Navy. Dewar and Gertrude had one son together, Kenneth Malcolm J. Dewar. First World War In August 1914, Britain went to war with Germany, and later that year with the Ottoman Empire (modern-day Turkey). Prince of Wales remained in the 5th Battle Squadron until 1915, when with a number of other pre-dreadnoughts she was sent to the Eastern Mediterranean to support the Gallipoli landings, the goal of which was to capture the strategically important Dardanelles Straits, take Constantinople and knock the Ottoman Empire out of the war. As second-in-command of Prince of Wales, Dewar was present for part of the naval operations in the Dardanelles Campaign against the Turkish positions. Following aborted attempts to lend heavy-gunfire support to the troops at ANZAC Cove, Dewar wrote an unofficial memo to the Rear-Admiral commanding the Eastern Mediterranean Squadron, with suggestions for the employment of indirect fire to attack Turkish targets. Dewar heard nothing of his proposals, and it was not until November 1915 that indirect fire was used with good effect by the bulged cruiser Edgar. Following the campaign, in October Dewar was given command of HM Gunnery School, Devonport. It was an important position as large numbers of Reserve and Volunteer Reserve officers either re-qualified or qualified in gunnery duties. After a year Dewar returned to sea in command of the Abercrombie class monitor Roberts, and joined the Dover Patrol in August, 1916. In response to the German battle cruiser raids on the British coast, a visible response was called for to quell public anxiety. On 27 May 1916, Roberts arrived at Gorleston to act as a guard ship for the port of Yarmouth, in effect acting as a coastal defence battery. Roberts fulfilled such duties at Tyneside and in the Thames Estuary for the rest of the war. Once again, Dewar was rotated back to shore, and was appointed to the Operations Division of the Naval Staff under first the Jellicoe, and then the Wemyss Boards of Admiralty. Dewar was promoted to the rank of captain on 30 June 1918 in the Half-Yearly lists and then became Assistant Director of Plans in the Plans Division. On 17 October 1919, he was appointed Commander of the Order of the British Empire (CBE) "for valuable services at