Two torpedo boats, No. 419, trial speed 20.82 knots, mean steam pressure 115 pounds per square inch, vacuum 23 and a half inches of mercury, mean revolutions of main engine 456 revolutions per minute and No. 420, trial speed 20.64 knots, mean steam pressure 115 pounds per square inch, vacuum 24 inches of mercury, mean revolutions of main engine 466 revolutions per minute, were built by Yarrow and Co., Poplar, for the Russian Government and later purchased by the English Government. The speeds achieved by these vessels were unequalled by any sea-going vessel afloat at the time.