They were built by Palmer's Shipbuilding Company, were 215 feet long and displaced 360 tons. Their Reed boilers produced 5,900 hp (4,400 kW) which gave them 30 knots (56 km/h; 35 mph). They were armed, as was standard, with one 12-pounder gun and two torpedo tubes. They carried a complement of 63 officers and men. The boats had funnel caps and the steam pipes of the middle funnel were not in the centre line. They served in the Mediterranean and home waters.