On the first of October, 1805, captain Siccombe, in a galley with eight men and his coxswain, placed two Torpedoes in the manner described, [Plate IV, Fig. 2], between the buoy and cable of a French gun-brig, in Boulogne roads. The tide drove them until they both lay perpendicular to her sides. When the French saw captain Siccombe advancing without answering the countersign, they exclaimed that the infernal machines were coming, and fired a volley of musketry at his boat, but without touching a man.[C] The moment the French fired, fearing the effect of the explosions, they all ran aft and were in the greatest confusion. The tide drove captain Siccombe's boat so far down, that he was obliged to cross under the brig's stern, where, seeing her men collected, and expecting another volley, he discharged at them two blunderbusses, each containing fifteen half-ounce balls[D], and was rowing away, when both Torpedoes exploded, but, to his astonishment, the brig was not destroyed. On the same night, lieutenant Payne, of captain Owen's ship l'Immortality, placed two Torpedoes across the bow of another French gun-brig; he received their fire, had one man wounded, rowed to some distance, and waited till he saw the explosion of the Torpedoes, which did not appear to do any injury to the vessel. When captain Siccombe called on me in the morning and reported these circumstances, I was much at a loss to account for the brig not being blown up. Defective in the experience which this failure gave me, I had not reflected, that if the copper case, with the clockwork and powder, weighed specifically fifteen or twenty pounds more than water, it would hang like a heavy pendulum to its suspending cork-box C, and if the coupling line were fixed in the centre of the end, as at A, [Fig. 1], the action of the tide being equal on both sides, would have no tendency to sheer or drive it from its perpendicular position. After about half an hour's consideration, I was forcibly impressed with this error in arrangement, as the real cause of captain Siccombe's and lieutenant Payne's failure.
[C] They had got some idea of these machines, from an attempt which had been made with them against the Boulogne flotilla, in Oct. 1804, called the Catamaran expedition.
[D] The report on this attack in the French papers, acknowledged that the brig had five men killed and eight wounded: this from two blunderbusses shews that the persons in the vessel attacked have to fear the small arms of the Torpedo boats.
I immediately had a large tub made, then filling a copper case with powder, I screwed on to it the clockwork lock, and tied to it the pine box C, then suspending the whole Torpedo by a line in the tub of seawater; the end of the suspending line was tied to one end of a scale-beam. I then filled the pine box C with cork, until the whole volume of the Torpedo and box of cork would, when just covered with water, hold three pounds in equilibrio in the scale on the other end of the beam. The Torpedo being then three pounds heavier than water, had a sufficient tendency to sink; and being so balanced, would, while under water, be easy moved by a slight pressure to either side. Then, instead of tying the coupling line to the end of the Torpedo, as at A, I tied it to a bridle, as at B, which presenting the side on an angle to the tide, the pressure of the current in the direction of the arrow, would cause the Torpedo to sheer from B to G. This arrangement perfectly succeeded to sheer the Torpedo from its perpendicular C, and the side of the vessel to E, near the keel, a position, near which it should be to do execution. In this situation, the explosion being under the vessel, would have a great body of water to remove laterally, before it could get out by a line curving round her side. The water, when acted on in so instantaneous a manner as by the explosion of one hundred or one hundred and fifty pounds of powder, does, for the instant, operate like a solid body; hence the explosion raises the vessel up with a great force, acting on a small portion of her bottom, which portion giving way, is the same in effect, as though a high sea had lifted her fifteen or twenty feet, and let her down on the point of a rock of three or four feet diameter. This, I believe, accounts for the certain destruction which will follow all explosions that take place near the keel. In all cases when the explosion is under water, the action will be perpendicular to the surface, as from B to C, for in the perpendicular, there are less particles to remove, and less resistance than in any diagonal, as for example, from B to D.
The French papers, giving an account of the attack of captain Siccombe and lieutenant Payne, acknowledged that the Torpedoes blew up along side of the gun-brigs, but gave them only a violent shock and cant to one side; they spoke of the engines as things of little consequence and not to be feared. It is now, however, evident, that they owed the safety of the two brigs to the trifling circumstance of the Torpedoes not being properly balanced in water, and the coupling lines not being tied to a bridle, so as to make the Torpedoes sheer under the bottoms of the brigs.
Is a bird's eye view of a ship of the line, either at anchor or under sail, and the Torpedo boats rowing on to the attack. I am sensible that there are strong prejudices against the possibility of row-boats attacking a ship or ships of the line, with any reasonable hope of success; I will, therefore, commence my reasoning and demonstrations by the following questions. What is the basis of the aggression and injustice of one nation towards another? Is it not a calculation on their power to enforce their will? What is the basis of all courage and obstinate perseverance in battle? Is it not a calculation on some real or presumed advantage? A frigate of 30 guns is not expected to engage a ship of eighty guns, for every rational calculation is against her, and to strike her colours would be no dishonour. If I now prove that all the calculations are in favour of the Torpedo boats, it shall hereafter be no dishonour for a ship of the line to strike her colours, and tamely submit to superior science and tactics.
I will run my calculations against a third rate, an 80 gun ship, she being the medium between first rates of 110 guns and fifth rates of 44 guns. I will suppose her to enter one of our ports or harbours in a hostile manner; her draft of water, when loaded, is twenty-two feet; her full complement of men six hundred. Were we to oppose to the enemy an 80 gun ship, she would cost four hundred thousand dollars; we would also have to give her a full complement of six hundred men. If she engaged the enemy, the chances are equal that she would be beaten; if an obstinate engagement, she might have from one to two hundred men killed and wounded, and be so shattered as to require repairs to the amount of forty or fifty thousand dollars; she might be taken and lost to the nation, and add to the strength of the enemy. It is now to be seen if six hundred men and a capital of four hundred thousand dollars, the value of an eighty gun ship, cannot be used to better advantage in a Torpedo attack or defence.