A summary of A F Yarrow's paper presented to the United Service Institute on the 9th of May 1884. In 1877 100 torpedo boats were ordered by the Russian Government, built from working drawings supplied by Yarrows by five Russian and two English firms, these boats (length 75 feet, beam 10 feet) were only capable of keeping the sea for a few days, but at the same time were small enough to be transported by rail from the Baltic to the Black Sea. Yarrow also supplied as many sets of machinery as could be completed before the Baltic was closed to navigation. During its trials on the Neva in November 1877 the first boat achieved a trial speed of 18 knots. Several boats were forwarded by rail to Sebastopol with only their funnels removed. After a journey of one week they arrived at Sebastopol and after the funnels had been replaced they were fit for sea-going service. At about the same time the English Government had ordered their first boats Lightning class torpedo boats from Yarrows and in 1879 one of these achieved a trial speed of 21.94 knots under Admiralty Conditions, beating its rival by nearly two knots. The load carried was six and three quarter tons, consisting of torpedoes, gear, coal etc. It was also fitted with a forward rudder to improve its steering powers. In 1878 two first-class boats were built for the Russian Government, but they were not allowed to leave England and were subsequently purchased by the Admiralty. An accident with one of these led to the introduction of a system of light non-return valves so arrange that any backrush of flame or steam closed them and cut of all communication between the boiler and the stokehold. The Batoum (length 100 feet, beam 12 feet 6inches) was built for the Russian Government in late 1879 and was fitted with a 500 indicated horsepower engine, and carried sufficient coal to travel 800 miles at moderate speed. It was armed with four Whitehead torpedoes, which could be discharged from two bow-launching tubes placed parallel to the centreline of the boat, and projecting just beyond the bow. The success of the Batoum led to further orders for boats of this type being placed by the Argentine, Greek, Brazilian, Austrian, Dutch and Italian Governments. Between 1879 and 1880 Messrs. Thornycroft and Yarrow and Co built thirty-four second-class torpedo boats for the Admiralty. At first these boats were equipped with launching frames for Whitehead torpedoes, but these were later replaced with Yarrow's steam impulse gear. The maximum trial speed achieved by these second-class boats was 17.27 knots. A torpedo boat collision in Italy led to Messrs. Yarrow and Co. introducing a special system for preventing water entering the vessel and cutting off the supply of air to the fires. The results of a trial between two first-class torpedo boats built for the Russian Government, one built by Messrs. Thornycroft and Co. and the other by M. Normand were also recorded. The former boat (length 113 feet, beam 12 feet 6 inches) achieved an average speed of 18.96 knots over three hours, burnt 2 tons 19 hundredweight of coal, producing 633 indicated horsepower in the process. M. Normand's boat (length 124 feet, beam 11 feet 8 inches), Achieved an average speed of 18.5 knots over three hours, burnt 1 ton 19 hundredweight of coal, producing 574 indicated horsepower in the process. The relative calorific value of the fuel used was not known, In 1884 two first-class torpedo boats with revolving torpedo tubes were built for the English Government. Alfred Yarrow considered the second-class boats being built at the time to be rather long and narrow and preferred boats with a length of 56 feet and a beam of 9 feet with a speed of 15 knots; the loss in speed being more than compensated for by improved handling and seaworthiness. He was also of the opinion that the English Government was lagging behind other Governments in their purchases of torpedo boats capable of operating at sea in all weather conditions.