LONDON TO MARGATE IN 1818. Paddle steamers still voyage up and down the Thames, but one of the first vessels to ply on this service was the London Engineer, shown here in section. The picture illustrates the cabins fore and aft and the boilers and engines amidships. The paddle-
FOLLOWING the introduction of paddle steamers on the Clyde and on the rivers of America and Europe, the Thames in due course received attention. In 1818 a wooden steamship was built for voyages between London and Margate. Thousands of Londoners and others have journeyed from the City to Margate by paddle steamer since these early days, long before the railways, and three years after Wellington’s victory on the field of Waterloo.
The London Engineer was constructed by Brent of Rotherhithe, and her engines were by Maudslay, Sons and Field. This vessel was 120 feet in length, 21 feet wide, draught 5 feet. By builder’s measurements her tonnage was 315. The engines, of the bell-
We have seen, in the previous chapter, the development of the steamboat from its first introduction to the general adoption, about 1820, of the side-
During this period, the firm of Boulton and Watt introduced the side-
The original engines had cylinders 4 ft. 6 in. diameter, with a stroke of 5 feet, supplied with steam at a pressure of 8 lb. from tubular boilers. These engines drove 20-
The pivoted beam was arranged to keep the engine’s centre of gravity as low as possible and to save head room. It was the custom in those early days of steam to ornament the large stationary engines on land, and the extension of the practice to marine machinery is demonstrated in the model by Gothic framing supporting the paddle shaft.
H.M.S. Gorgon, a steam frigate of 1837, was equipped with direct-
Much of the credit for the development of the side-
This river steamer, built at Dumbarton, Napier’s birthplace, was one of the first to ply between that town and Glasgow. The engine has a single cylinder of 2 ft. 7½ in. diameter and 3 feet stroke, and it is now preserved at the pierhead in Dumbarton. Robert Napier’s practice before 1845 was to employ two cylinders driving cranks set at right angles. This arrangement ensured an even turning movement of the paddle shaft and facilitated starting. An interesting property of the side-
In 1840 Napier’s side-
Among other interesting side-
The engines of the Ruby, built by Seaward and Co., consisted of two cylinders 3 ft. 4 in. diameter by 3 ft. 6 in. stroke. Steam was supplied by flue boilers at a pressure of 3½ lb. The engines developed 100 h.p. and drove a pair of paddle-
The engines, in common with most side-
Many attempts were made to reduce the space required in a ship by the side-
This compromise gave place to the direct-
The two cylinders were of 5 ft. 4 in. diameter with a stroke of 5 ft. 6 in., and were carried on foundation plates each weighing 10 tons. These plates contained also a condenser and hot-
Steam was supplied by four tubular boilers. There were twelve furnaces fed with coal from two stokeholds. The coal bunkers, holding 400 tons, were arranged round the machinery, so affording a protection some 8 feet in thickness. The engines gave a speed of 9| knots on a fuel consumption of one ton of Welsh coal an hour. The Gorgon, of 1,111 tons, was built of teak with oak main beams and measured 178 feet in length, 37 ft. 6 in. in breadth and 23 feet in depth. The paddle wheels were 27 feet in diameter.
“STEEPLE” ENGINES were at one time popular in paddle steamers. Their design effected economy in space and permitted the use of long connecting rods. These engines acquired their name from the “steeple” appearance of the guides projecting above the deck. This model, in the Science Museum, South Kensington, was formerly used for propelling a small boat and has cylinders 41 in. diameter by 5⅓ in. stroke. Each piston has four rods attached to a crosshead from which the connecting rod extends downwards to the crankshaft.
H.M.S. Gorgon was one of the first steam warships in action and in 1840, with three paddle sloops, Vesuvius, Stromboli and Phoenix, she took part in the bombardment of Acre under Admiral Stopford. With a complement of 160 men she carried six guns on the upper deck, of which two were 10-
Although the engine arrangements of the Gorgon represented a definite improvement in space and weight, an objection raised against the design was the shortness of the connecting rods, imposing a heavy strain on the parallel motion guiding the piston rods.
One of the first sets of engines built to this design was installed in the paddle steamer Sapphire, an iron vessel built by Ditchburn and Mare in 1842. The Sapphire was 150 feet long and had a beam of 19 feet and a draught of 4 ft. 6 in. The three cylinders were arranged under the paddle shaft and were each 6 ft. 2 in. in diameter with a stroke of 3 feet. The steam pressure was only
8 lb. per square inch. Paddle-
Another arrangement of direct-
THIS FINE MODEL represents the engines of the paddle steamer Ruby, built in 1836 for service on the Thames between London and Gravesend. The engines were of the side-
“Steeple” engines took their name from the appearance of the piston-
The next advance in steeple engine design was in 1839, when Joseph Maudslay and Joshua Field jointly patented a “return connecting-
The piston of the Maudslay-
An interesting model of a quadruple piston-
Napier’s steeple engine was further improved at a later date by the use of only two piston rods instead of four. The cylinder was placed vertically beneath the crankshaft, and the two piston rods passed through the top cover, extending upwards on either side of the shaft. Above the crankshaft, the piston rods were joined together by a crosshead working in cylindrical guides. The connecting rod worked downwards from the crosshead on to the crankshaft. From the crosshead also were worked the air-
Several engines of this type were built for the East India Company in 1850. The engines were of 30 h.p., with single cylinders 2 ft. 8 in. diameter by 3 ft. 6 in. stroke and were for use in shallow-
Methods of providing a long connecting rod for the paddle engine continued to be devised. The use of a “return piston rod” proved an interesting addition to the various devices employed, and in this type of engine a single piston rod was terminated in a four-
In 1843 a type of paddle engine was introduced with inverted cylinders and connecting rods returning upwards to the crankshaft. A set of these engines, by G. Forrester and Co., was installed in the paddle steamer Helen McGregor, built by John Laird at Birkenhead. These engines comprised two inverted cylinders, 3 ft. 6 in. diameter by 4 ft. 6 in. stroke, carried on four wrought-
The dimensions of the Helen McGregor, built for the Hull and Hamburg trade, are interesting, as she was at the time one of the largest vessels of her class. The length was 180 feet, breadth 26 feet, depth 15 feet with a register of 573 tons.
THE HELEN McGREGOR, a paddle steamer of 573 tons, was built at Birkenhead in 1843 and fitted with engines of the type illustrated here. The cylinders, 3 ft. 6 in. diameter by 4 ft. 6 in. stroke, were carried in an inverted position on four wrought-
The foregoing variations in paddle engine design do not exhaust the number of ingenious arrangements resorted to by the earliest marine engineers. The double-
There were two engines, each with two cylinders, 6 feet diameter by 8 feet stroke, placed in a fore-
In a later chapter will be described one of the most fascinating of all marine engine types, the oscillating engine.
ROBERT NAPIER’S CLYDE-
[From part 12, published 28 April 1936]
“Propelling the Modern Ship” on this website.