The official trial results of the twin-screw torpedo-boat destroyers Rocket, Shark, and Surly (length 200 feet, beam19 feet 6 inches, draught 6 feet 9 inches; displacement 280-325 tons) fitted with two 18.125-inch by 26.625-inch by 40.125-inch by 18 inch stroke inverted-vertical triple-expansion marine engines operating on steam supplied by four Normand water-tube boilers; armament, one double set of torpedo tubes mounted aft, one 12-pounderquick-firing gun, and two 6-pounder guns, built by Messrs. J. and G. Thomson, Limited, Clydebank, for the Royal Navy.