“It’s the trimming-tanks that keep her level,” he explained. “As we’re walking forward, our weight in water is being automatically pumped from the trimming-tank in the bow to the one astern. A submarine is just one blamed tank after another. Stand clear of that chain-fall, sir; they’re loading No. 1 tube.”
Stripped to the waist like an old-time gun-crew, four beautifully muscled young gunner’s mates were hoisting, with an ingenious arrangement of chains and pulleys, a torpedo from the magazine. The breach of the tube was opened and the long Whitehead thrust in, two flanges on its sides being fitted into deep grooves in the sides of the tube, so that the torpedo would not spin like a rifle-bullet but be launched on an even keel. The breach was closed, and the men stood by expectantly.
“Skipper’s up in the conning-tower, taking aim through the periscope,” explained the man who had told me about trimming-tanks. “The tubes being fixed in the bow, he has to train the whole boat like a gun. Likewise he’s got to figure out how far it is to the target and how fast the tug is towing it, how many seconds it’s going to take the torpedo to get there, and how much he’s got to allow for its being carried off its course by tide and currents. When he gets good and ready, the lieutenant’ll press a little electric button and you’ll hear—”
“Thud!” went the compressed air in the tube, and the submarine shuddered slightly with the shock of the recoil. But that was all.
“There she goes!” said my friend the tank-expert. “As soon as the Whitehead was expelled, a compensation-tank just above the tube was flooded with enough water to make good the loss in weight.”
“What keeps the sea-water from rushing into the tube after the torpedo leaves it?” I asked.
“A conical-shaped cap on the bow of the boat keeps both tubes closed except when you want to fire one of them. Then the cap, which is pivoted on its upper edge, swings to port or starboard just long enough for the torpedo to get clear and swings back before the water can get in.”
Four of the ten torpedoes carried in the magazine were sped on their way to the unseen target. I returned to the turret as the wireless operator entered and handed a typewritten slip to Lieutenant Scope, who smiled happily and said to me,
“The captain of the tug reports that all four shots were hits and all four torpedoes have been safely recovered.”
I was too astonished to congratulate him on his marksmanship, as I should have done.