Members of the Society of Engineers inspected the extensions to the Chatham Dockyard and whilst there inspected the torpedo ram Polyphemus (length 240 feet, beam 40 feet, draught 19 feet 9 inches; displacement 2610 tons; estimated speed 17 knots). The Polyphemus was fitted with two 38-inch by 64-inch by 39-inch stroke 5,5000 indicated horsepower horizontal compound marine engines operating on steam supplied at 120 pounds per square inch by ten locomotive boilers, driving two propellers. Armament, one bow and four broadside 14 inch submerged torpedo tubes. Accession No.54. 'Sea-going torpedo boats.' The Engineer, vol. 50, 3 December 1880. p. 417. Torpedo boats of the Batoum class (length 100 feet; trial speed 22 knots) built for the Russian Government by Yarrow and Co., Poplar, were favoured by a number of foreign governments because of their good sea-going qualities. Yarrow and Co. had also improved their armament by increasing the number of bow torpedo tubes to three.