Nelson smiled. “When you know how. But look here, Townsend. After you’ve shot your first torpedo where do you get water from to fill the tube around the next one? Your tank’s empty, isn’t it?”
“Right-o! But listen to me, old settler. When your ‘moldie’ leaves the tube the water flows into it. The weight of that water is only a few hundred pounds less than the weight of the torpedo and water together was before. So next thing we do we close the outer cap again. Then we pump seven hundred pounds of that water back into the filling tank. After that we blow the rest of the water in the tube into what’s called the compensating tank. Now, then, we’ve still got the same weight aboard as we had before we parted with Mr. Torpedo. Do I make myself plain?”
“Quite, thanks. It—it’s rather wonderful, isn’t it?”
“Well, it’s ingenious. I’ll say that much for it. After all the water is out we open this inner breech again and we’re all ready to slip in another torpedo. And that’s how that’s done! Jimmy here could have doped it out better for you, but I guess you’ve got the general idea. How’s the air, fellows?”
“Getting a bit thick, I’d say,” replied the one alluded to as Jimmy. He sniffed knowingly and then took a deep breath. “Wonder how it is on the surface.”
“Blowing like the Old Harry, I guess. When did we dive? I was asleep.”
“About three-twenty, I think it was. We’re good for another fifteen or sixteen hours yet, but I hope he’ll pop up before that. It’s the battery smell that gets me. I can taste the stuff already.”
“Can you really stay down as long as he said?” asked Nelson as they made their way along the passage to the after quarters.
“We can stay down as long as our battery holds out, which at four knots an hour, about what we’re doing, would be from twenty-two to twenty-four hours. Anyway, that’s what they say. I was never down more than four hours until now. As far as the air is concerned, I guess no one knows how long this tub could stay down. I dare say the air would hold out about as long as the battery, though. That needn’t worry you, Nep. We’ll be popping out long before that.”