Airships Float?

There was no more line left, so they untied coils and coils of it from the still sleeping yeti and secured Gerhardt with that. He scrambled up again, let a little gas out of each balloon, and fastened the net closer to the ship.

They sank closer to the river’s rushing water, and were on their way for a while. But before another ten leagues had passed, they were stuck again.

“What else can we pitch?” Claire asked, thinking aloud.

They looked around them. They had thrown all the rugs and blankets out the windows for Ulrik and the boiler crew back on the surface. They had tossed out all the furniture when they’d run aground in the tunnel.

“Water!” Annabelle seized a small barrel. “There’s plenty of water now, let’s dump it. There’s another one over there.”

The second barrel proved not to be water, but a sharp-smelling, eye-watering alcohol.

“Sake,” Adolphus said. “It can go, but the boiler chaps won’t be pleased with us.”

They dumped both barrels and a crate of machine parts that Claire had stashed as being potentially useful, but it was not enough.

“We can’t toss the gas tank,” Claire said, “or we won’t be able to refill the balloons when we need it.”

“If we die stuck in this tunnel, we won’t need more gas!” Adolphus countered.

Water seeped in through the floorboards, sluggish but sure. Water is patient, far more patient than children, for it has all the time in the world.

“Blasted monkeys! Why isn’t this hull sealed?”

“Language, Adolphus,” Claire said. “The hull isn’t sealed because they built an airship, not a submarine.”

Annabelle and her sister closed the windows. The windows didn’t seal any better than the hull, and on the starboard side the glass was all broken out.

“I say, leave me a bucket and I’ll bail out some of this water,” Gerhardt, ever practical, started heaving river water out of the broken windows.

They heard a terrible coughing, slamming stutter, and then ominous silence as the engines died in the flood. Now the sagging balloons were the only thing between them and the river.

“How much do you think this craft weighs,” Mirabelle asked no one in particular, “compared to the volume of water it displaces?”

“You mean?”

“Sink or float?” Bettina said.

“I wonder how close we are to the end of the tunnel?” Claire was not addressing any of her siblings, but Adolphus and the twins answered nevertheless.

“Could be miles, yet!”

“It could end in an underground lake!”

“It could end in a waterfall, and we could plummet to our deaths!”

“Not if we still have gas, we wouldn’t.”

“You’re the one who wants to let all the gas out, Adolphus.”

“We’d get unstuck if we did!”

“We might sink if we did.”

“We might not!”

“Would you three keep it down?” Gerhardt said. “I’m trying to figure the rate at which the water is seeping into the hull, and I can’t hear myself calculate the D’Arcy-Weisbach  friction coefficient.”

“What we need is weight versus displacement,” said Mirabelle.

“But that won’t matter,” Gerhardt replied, “if the hull is so unsound that the water reaches the smashed windows.”

“We should detach the balloons,” Adolphus said. “Let’s just get unstuck.”

“Oh sure, let’s just drown!” Annabelle snapped.

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This story began with On Grandmothers. The previous episode is Stuck! and the next is Where is Claire?