 All vessels had a distinctive "turtleback" forecastle that was intended to clear water from the bow, but actually tended to dig the bow in to anything of a sea, resulting in a very wet conning position.They generally displaced around 260 tons and had a length of around .All were powered by triple expansion steam engines and had coal-fired water-tube boilers (although initially, some had "locomotive type" fire-tube boilers in lieu).