London Times, 5 October 1850, p. 6: THE EMPEROR OF RUSSIA'S STEAM YACHT

This fine frigate-rigged steam yacht, named Peterhoff, built of iron by Messrs. Mare and Co., Blackwall, from a design by Mr. Waterman, jun., and fitted with engines of 140 horse power by Messrs. George and Sir John Rennie, went down the river to-day on an experimental trial, having on board Lieutenant Echapparie, Lieutenant Korchakoff, and Lieutenant Semenoff, of the Russian navy; Sir John Rennie, Mr. George Rennie, Mr. Bishop, patentee of the disc engine, Mr. Dykes, engineer, Mr. Waterman, designer of the vessel, and Mr. Jones, chief draughtsman to the Messrs. Rennie. The Peterhoff is of 412 tons burden, and draws 3 feet 11 inches forward, and 4 feet 2 inches aft; and when she started on her trial to-day she had all her rigging up, as she is to leave in the course of next week for St. Petersburgh. Her cylinders are 46¼ inches diameter, on the oscillating principle, and give a stroke of 3 feet 6 inches. The engines are finished in the best style, and have been adjusted with such nicety that during her run from Blackwall to the Nore, and six times up and down the measured mile in Sea Reach, below Gravesend, there were not the least symptoms of heating in any part, and the movement of the vessel at her greatest speed did not produce the least vibration in whatever part she was tried. The result of the six runs in the Sea Reach gave an average speed of 14.575 knots, or 16.789 miles per hour, which was very satisfactory on a first trial, especially as a portion of inferior coals was mixed up with the others. During the time she ran the measured mile the number of revolutions of the engines was 36 per minute, with a pressure of 15lb. to the square inch. She has feathering paddle wheels of 18 feet diameter to the outside edge, constructed in the ordinary way, and these wheels, with the other parts of the engines, are remarkably light, it being of the utmost importance that the vessel should only draw about four feet water. Considering the size of the yacht, and that she is capable of sea service, the speed attained is considered very good, and gave entire satisfaction to the Russian authorities on board. The double eccentric gear used in the engines, by which they may be reversed instantaneously without shutting off the steam, is a great improvement, and renders her working so simple as to be attainable by the meanest capacity. The fittings of the yacht are very substantial, and display a great deal of taste. Altogether this fine yacht is a credit to her constructors and the makers of her engines, and exhibits a proof of the great perfection that the building of ships and the making of marine steam engines have been brought to in this country.