“Ram home!” he ordered. The great, cigar-shaped projectile, with its tiny, fairy-like propellers and bright metal work gleaming wickedly, was slid into the tube. With a sharp click and snap the water-tight breach of the tube was at once closed. The torpedo was ready for firing.
Before ramming home, however, the “war head” had been placed in the implement. This means that the dummy-head had been removed and one charged with gun-cotton had been substituted for it. Vessels at sea do not carry war heads on their torpedoes. It would be too dangerous. The cap, full of disaster-wreaking explosive, is not put in place till they are to be used.
This done, Lieutenant Parry stood by the inner end of the tube, his hand on a lever. When this was pulled, it would admit compressed air to the tube, which would simultaneously open the outer end of the contrivance and launch the torpedo. At the same time the pressure would keep the water out of the tube. The boys knew that in the Lockyer type of boat, besides the compressed air, the torpedo was helped on its way by a charge of the explosive gas being touched off behind it. This was effected by the compressed air, on its being turned on, operating a small firing point, which sparked and instantly exploded the volatile stuff.
On the top of the torpedo was a small knob. As the torpedo was shot out of the tube, much as a bullet is shot from a rifle, this knob struck another projection on the inside of the tube. This set in motion the compressed-air engines within the torpedo, by which it was driven. At the same time it ignited an alcohol flame which superheated the compressed air, giving it added force.
With all in readiness, they waited breathlessly for the signal to come from above. Lieutenant Parry’s foot tapped nervously, as they stood in silence. His eyes were fixed on a small incandescent bulb, wired directly from the conning-tower. It would flash red when all was ready for him to pull the lever and release the instrument of destruction.
“We’re sinking, sir,” said Ned presently.
The officer merely nodded. The moment was a tense one. There is something to fire the dullest imagination in the idea, that by a mere twist of a wrist, one is presently to launch forth one of man’s most effective engines of devastation.
Only the loud swishing of the water as it rushed into the tanks broke the silence now. All at once, the downward motion—like the falling sensation of a slow elevator, ceased.
Suddenly, above the officer’s head, there was a tiny, crimson flash.
It was the signal he had been waiting for.