3-034-584 - The Print Collector/Heritage Images

The Prince of Wales's new steam-yacht Osborne, 1871. Royal yacht built at Pembroke Dockyard. 'Her engines are from the workshops of Maudslay, Sons, and Field, and are of the nominal power of 450 horse. The cylinders, oscillating, are 80 in. in diameter, with a stroke of piston of 7 ft. The two paddle-wheels are each 27 ft. 6 in. in diameter, are fitted with feathering floats each 11 ft. 6 in. in length by 3 ft. 7 in. in breadth. The emersion of the lower floats with the ship at her load line is 2 ft. 3 in., measuring from the upper edge of the lower float. Four boilers, each having 450 brass tubes, supply steam to the engines, and are leaded to 30 lb. to the square inch on the safety valves. The two funnels are each 72 in. in diameter, and stand 46 ft. above the fire-grate. The superheaters have flattened tubes, the steam passing through the tubes at the chimney root. The superheaters can be shut off very easily when required and with the boilers at work. The coal-carrying capacity of the ship is very limited, being only equal to thirty hours' steaming at full speed'. From "Illustrated London News", 1871.