The previous classes of 'destroyer' were more in the 'torpedo boat' size of vessel. They had been built as harbour protection vessels and the 1910 versions had been the first of the size to be turbine driven. With only two 3" / 12 pounder guns they were not over armed, it was their four single torpedoes (two to a side) that were their big teeth. It was not till the Royal Navy L class that Greenland took notice of full destroyers that would be able to screen the battle fleet. The first copies of the L class, built in 1913/14, were not as good as they had hoped. It was the ships speed at 30-32 knots that was the problem. The 1913 Malchus class battleships were making 26 knots and there was not enough of a speed differential to allow those destroyers to do the screening work. It was the Sapphire class making 35-36 knots that proved to be the answer.
The Greenlandian version of the M-S class vessels were slightly larger than their Royal Navy equivalents. The RN ships were designed for operations mainly in the North Sea. Short range trips. The Greenlandian Navy operated in the central Atlantic where the distances were far greater and their destroyers needed a larger radius of action. The difference between the Sapphire and later Emerald class was in the fuel types, the Sapphires were coal fired, the Emerald class were oil fired. The remaining twenty ships were converted to oil firing during the early 1920's. Four ships of the class were lost during the war on convoy duty.
The class, being larger, was able to introduce some key features to Greenlandian destroyers. The use of a rangefinder for the 4" guns improved accuracy at medium to longer range shoots, this was mounted on the roof of the bridge superstructure. The same applied to the rangefinder for the torpedoes mounted on the aft superstructure. The torpedoes went from twin to triple 18" sets. AA machine guns were mounted between the torpedo sets.
Twenty years of service in and the Sapphire class are on the bottom rung of the duty roster. Next rung down is the scrap heap. The Treaty failures of the early 30's threw a lifeline to a lot of the older sips that had fought in World War One. The twenty ships of the Sapphire class are surveyed to see which ships were still in good enough condition to have money spent on them to extend their service lives another ten years. Fourteen ships passed the survey and were slowly upgraded. The upgrades were around improving the AA capability of the class. All of the old 4"/40cal guns were removed and replaced with two 4"/50cal dual purpose guns with shields. The centre 4" was replaced with two single 2 pounder AA guns while a third 2 pounder replaced the 15mm machine guns between the torpedo tubes. The other change was to mount an improved dual purpose rangefinder above the bridge. The fitting of Asdic and depth charges gave the ships a decent ASW armament. These changes took the ships through to the start of WW2 when electronics started coming into service. By the the end of 1940 the ships had the aft set of torpedoes removed to reduce topweight from the electronics and to allow more space for depth charge throwers and storage.
