The team had worked out that a hydrogen-filled engine would get them enough extra power to make it more viable for a plane. That brought up another problem though. At the shop he said, "When one of these things leaks, the average shop won't easily be able to repair it. Relying on an exotic gas makes it that much harder."

"All the better for us," said Tazo. "We'll be the repairmen."

"From hundreds of miles away? Any machine will break sometime, and figuring out what to do about it is part of the design. Kotta's bike is an example of making a thing rugged for use far from a repair shop."

Ashfall shrugged. "Sell two versions, with or without the special gas?"

Vonn nodded. "For now, yeah. So, Birb, has the Baron's new order come in?"

"Ten motor fittings for small boats, with the boats to be provided for us."

"We can do it. But our weak point is woodworking for the propellers."

"We're getting an apprentice for that. Third level, hoping to hit fourth."

Tazo said, "Another name on the payroll. But we do need a specialist for that."

Vonn sent out a comment to the Baron to ask how much he cared about easy repair, and tried to explain the hydrogen problem. The man didn't have a science background at all, but might at least understand what Vonn was getting at.

Meanwhile, there was plenty of work to do. The Kobold twins had gotten good with the machine tools and had made their own set to take home later this year, and were cranking out more for sale. Ashfall was doing the usual hinges and shovels and locks but also contributing to the larger fittings for engines. The shop occasionally produced a new pinball machine or bicycle or crossbow, but those things couldn't be priorities right now.

They'd run into a capacity problem because of the System. Vonn's powers let him make a pressure container unusually sturdy and apply a second bonus against explosions. Also he could give any mechanical device one connection that was nearly frictionless. But the first of those abilities had an arbitrary limit of around once a week. His Chief Engineer ability let those Engineers under his command also use these powers. At this point that included Tazo, Birb, and the two Kobolds. So, five pressure containers per week, whether for wind guns or engines. No matter how efficient Vonn could make the manufacturing process, the quantity of items he made at that special quality had a hard limit by headcount. And once his "students" left, that would be minus two devices per week until he got more Engineers and they worked here long enough for the System to count them.

Over lunch one day he said, "So either I have to get some further upgrade from the System that removes that limit, or accept an innate limit to how much I can do."

Polestar was there, occupying most one corner of the restaurant. "We're not in the stage of having factories anyway. I like what your book did with the nod toward labor laws, by the way."

"Selen's idea. I found out that the rarity of diseases is due to special magic reasons, in a way that doesn't protect everybody from black lung in a coal mine or other safety problems. Even now there're probably some twelve-year-olds working underground someplace. I had ancestors who did that."

"Here, or...?"

"Both!"

Polestar grunted. "That number limit on your production sounds like a problem only for specific widgets. You can still crank out tools, right? And lower-quality pressure stuff if you have to."

"Not a great long term solution though."

"You'll think of something. You've already got a workaround for making good-enough models for planes, right?" The Centaur grinned. "And if you make quota for the week, you have an excuse to do other gadgets."

"Ha, yeah. I'm actually looking to take a business trip."

#

The new boat in progress was mainly his. It held an improved jet design suggested by Birb and Tazo: adding small holes to the sealed end. The tube's crystals created airflow which made low pressure, which sucked in more air from outside. That air got pushed along past the heating gems and forced out faster. The two Engineers had rediscovered the "Bernoulli effect". Overall, it meant more thrust for free.

There was also the bone upgrade. The necromancers had provided heat-resistant tubes of smooth, yellowed ivory, good enough to replace iron for this application, saving a few pounds when used in the right places. Vonn had set up a mechanical testing stand that allowed the bone-shapers to get measured, quantified records of how well their wares held up. Birb's own knacks helped her to explain the forces involved in literally bone-crushing experiments. In time, Vonn thought, the necromancers might be as important as producers of raw materials as they were in magically assisted labor.

He avoided asking exactly where the bones were sourced from in this case.

The boat itself was made for lightness. Not watertight, and using a floor mostly of wicker. The hardpoints were for the near-center engine and six downward-pointing jets, plus two more pointed backwards on a swivel mount. Vonn had only been able to boost the power output of the engine's gems and not the jets', which were in too simple a device to count as Engineer work. He wanted to argue to the System that the overall vehicle should count. There were a lot of parts.

He'd tried out the vessel with no balloon. The whole array of jets could hold up roughly the weight of themselves and the boat, sans engine, and he counted that as good enough. He expected several to break. They could slightly slow a crash, too. In a test, the wooden tub hovered just above ground and the team fooled around with the exact weight balance and ballast. They brought in some local kids to demonstrate how a balance of forces was important in the real world.

Above the hull were ropes linked to the balloon. After the team's experience with Birb's first blimp, they'd handled the sewing a bit differently and put more effort into durability, making the thing heavier but more reliable.