Steamships and their story

by E. Keble Chatterton

With this explanation in the mind of the general reader, to whom engineering matters do not usually appeal, we may proceed with the progress of our story, and pass on to the year 1730, when a method differing entirely from any that we have yet mentioned was brought forward. Strictly speaking it had nothing to do with steam, but, as we shall see when we come to consider the subject of steam lifeboats, it embodied an idea which could only be satisfactorily employed by the adoption of steam. In the year mentioned there was published a little book under the title “Specimina Ichnographica: or a Brief Narrative of several New Inventions and Experiments: particularly, The Navigating a Ship in a Calm, etc.,” by John Allen, M.D. The author’s idea was to propel a ship by forcing water, or some other fluid, through the stern by means of a proper engine. To this end he experimented with a tin boat 11 inches long, 5 inches broad and 6 inches deep. Placing this little ship into stagnant water, he loaded it until it sank in the water to a depth of 3¾ inches. Into the boat he also placed a cylindrical-shaped object 6 inches high and about 3 inches in diameter and filled it with water. At the bottom of the cylinder was a small pipe, a quarter of an inch square, and this led through the stern of the craft at a distance of an inch and a half below the surface of the water in which the boat was floating. As soon as Allen removed his finger from the outlet of the pipe in the stern the water, of course, ran out from the cylinder, and this action caused the boat to travel, the speed being reckoned, in the case of the model, at about one-fifth of a mile per hour. Although nothing actually came of this theory at the time, it is none the less perfectly workable, with some adaptations, and some of the steam lifeboats, in order to avoid using propellers, which are liable to get foul of wreckage when going alongside a ship in distress, have an elaboration of this principle. They are propelled by engines which work a pump that drives a stream of water through pipes placed below the water-line in much the same manner as in Allen’s model. Allen at first contemplated working the pumps by men, and then causing them to be driven by an atmospheric steam engine. A similar device was employed in Virginia, U.S.A., by James Rumsey in 1787. In his boat water was sucked in at the bow and ejected at the stern. It was found that as long as the vessel travelled at all she went at the rate of four miles an hour, but as she only covered less than a mile and then stopped, it cannot be said that this experiment was conclusive. In 1788, the following year, however, another boat was made actually to go a distance of four miles in one hour, and the device was patented in that country during the year 1791, but Allen had already patented his invention in England thirty years earlier.

It is when we come to Jonathan Hulls or Hull that we encounter the first Englishman to apply steam to ships. Hulls was a native of Gloucestershire, who, in 1736, patented a method of propelling vessels by steam, and in the following year issued a booklet on the subject of his invention which was subsequently reprinted. The title reads thus: “A Description and Draught of a New-Invented Machine for Carrying Vessels or ships out of or into any harbour, port or river, against wind and tide or in a calm ... by Jonathan Hulls.” His idea was to provide a steam tug so that it should be able to render beneficial service to those sailing ships accepting it. His preference for placing the “machine,” or engines, into a separate ship, and thus using her as a tug-boat, instead of installing the engines on board each vessel was because he believed the “machine” might be thought cumbersome and take up too much room in a vessel laden with cargo. But besides the advantage of having a tow-boat always in readiness in any port, he suggested that an old ship which was not able to go far abroad could well be adapted for receiving this “machine.”

“In some convenient part of the Tow-Boat,” he explains, “there is placed a Vessel about two-thirds full of Water, with the Top close shut. This Vessel being kept boiling, rarefies the Water into a Steam: this Steam being convey’d thro’ a large Pipe into a Cylindrical Vessel and there condens’d, makes a Vacuum, which causes the weight of the Atmosphere to press on this Vessel, and so presses down a Piston that is fitted into this Cylindrical Vessel in the same manner as in Mr. Newcomen’s Engine, with which he raises Water by Fire.”

It will thus be seen that Hulls was an adapter of Newcomen’s atmospherical engine to marine purposes rather than an actual inventor of something new and unheard of. But Hulls seems to have anticipated this criticism, for he adds: “if it should be said that this is not a New Invention, because I make use of the same Power to drive my Machine that others have made use of to Drive theirs for other Purposes, I Answer, The Application of this Power is no more than the Application of any common and known Instrument used in Mechanism for new-invented Purposes.”

JONATHAN HULLS’ STEAM TUG-BOAT.

After the Drawing attached to his Specification for the Patent.

We have already noticed that the most which Newcomen could get out of his engine was an up-and-down movement, which was all very well for the purpose for which it was intended, namely, pumping up water, but before it was applicable for propelling a ship the power had to be adapted to give a rotary motion. [The accompanying illustration], which is taken from Hulls’ specification for his patent, and reproduced in the booklet mentioned above, will afford some idea of his proposal. In the lower half of the picture the “tow-boat” is seen in imagination hauling an eighteenth century full-rigged ship, a performance which in actual truth she never achieved. There is, in fact, some doubt as to whether Hulls ever did put the idea to a practical test. Admiral Preble, a distinguished American Naval officer, in his “Chronological History of the Origin and Development of Steam Navigation,” published in Philadelphia in 1883, a volume which contains a vast amount of interesting detail up to that date, says that Hulls did not produce a satisfactory experiment. Scott Russell, one of the greatest authorities on such matters in the nineteenth century, affirmed that Hulls did carry out his theory in definite shape, and the recent “Dictionary of National Biography” also states that at any rate he experimented with a vessel on the River Avon in the neighbourhood of Evesham in 1737. One thing is certain, that whatever merits the proposition might have had in certain respects, it was, commercially, a complete failure. On the other hand, in enunciating a method of converting the rectilineal motion of the piston-rod into a rotary movement Hulls undoubtedly showed the direction in which others were to follow.

In the upper half of [the illustration of Hulls’ drawing], beginning at the bottom right-hand corner, we see the details of his “machine.” P is the pipe which comes from the furnace and brings the steam to Q, the cylinder in which the steam was also condensed. (This last remark is important to bear in mind, as we shall see later to what extent this feature was modified.) The point marked R is the valve which enables the steam to be cut off from entering the cylinder whilst that amount of steam which has already been allowed to go in is being condensed. The other small pipe S conveys the cooling water which condenses the steam in the cylinder, and T is the cock which lets in the condensing water after the cylinder is full of steam and the valve is shut. U is the rope which is fixed to the piston that slides up and down the cylinder, and this is the same rope that goes round the wheel D in the machine shown in the larger illustration.

In this latter picture, too, wherein the tow-boat is seen steaming along, A denotes, of course, the chimney “coming from the furnace,” while B is the tow-boat and CC are the two pieces of timber which are framed to support the machine. It will be noticed that inboard are three wheels marked respectively Da, D, and Db. These are on one axis and receive the ropes as shown. Ha and Hb are two wheels also on the same axis projecting beyond the stern, and the six fans or paddles are marked I, which move alternately in such a manner that when the wheels Da, D, and Db move backwards or forwards they keep the fans or paddles in a direct motion. When these three wheels Da, D, and Db move forward then the rope Fb must move the wheel Hb forward, and so cause the paddles to revolve in the same direction. So also the rope Fa connects the wheel Ha to Da, and when the latter and its two sister wheels revolve the wheel Da, then the wheel Ha draws the rope F and raises the weight G (barely decipherable in the sketch to the left of Da), at the same time as the wheel Hb brings the paddles forward.