Myrmidon and Syren were built by Palmers Shipbuilding and Iron Company as part of the group of boats known as the 'thirty knotters'.

The boats were not able to make this speed in bad weather, where they were usually wet and uncomfortable with cramped crew quarters, but they proved their toughness in serving in the Great War, despite being twenty years old.

Myrmidon was sunk after a collision in 1917, while Syren served through the war and was broken up after the end of hostilities.

They were armed with the standard 12-pounder gun and two torpedo tubes and carried a complement of 63 officers and men.

Ships of this type bore four funnels and were designated B-class destroyers after a reorganisation in 1913.