 All vessels had the distinctive turtleback that was intended to clear water from the bows but actually tended to dig the bow in to anything of a sea, resulting in a very wet conning position and poor seaboats that were unable to reach top speed in anything but perfect conditions.They generally displaced around 350 tons and had a length of around 200 feet.All were powered by triple expansion steam engines for and had coal-fired water-tube boilers, except some unique "specials" that used steam turbines in addition to, or in lieu of, the reciprocating engines.