The next day, the 24th, the meeting started with Rodrigo's question.

"Jin-dono, from what you explained yesterday, the wind magic of <> is ......<< strong wind(wind)>>?　I'm not sure what you mean by that. ...... Oh, yeah, water molecules?　But can't you make it like air?"

Although the question was not clear to me in many ways, I understood what he meant.

"In short, you are asking if it is possible to make it so that the propulsive force does not change even if it is covered with water?

"Yes, that's it!　That's it!"

When wind thrusters are installed on the sides of the hull, the ship will inevitably suck in water when the waves are rough. The reason for this was that if the propulsive force fluctuates each time this happens, the ship will not be able to go straight, and this may be a problem when moving forward at a very low speed.

"...... might be able to do that."

If he answered immediately, it would sound too false, and he might be asked why he had not done so, so he replied cautiously.

"Oh, I see!　If so, would you consider improving that side of the hull?　The rest of us will discuss the hull.

"Yes."

Thus, Jin was left alone with Reiko to work on the improvement of the wind thruster in a separate room.

Elsa looked at Jin as he left for the other room with a slightly disappointed look in her eyes.

"Father, is it really that difficult?"

Reiko looked at her curiously. Hitoshi rebuked her.

"You're talking too loud. ...... can do that kind of modification in two minutes. But it's not good to go too far and make yourself look bad, is it?

He seems to be aware of this. That's unusual. I can almost hear him saying, "It's a little late for that now.

"I understand."

Jin then joins Reiko in dismantling the prototype of the wind thruster that he and Reiko made yesterday. He stood it in front of him, pondering.

However, what they are thinking about is something else.

"Even if it's not a geostationary satellite, it would be a landmark if we could embed a marker in the top of a mountain or something, but I wonder if it would still be dug up ......."

"I think so."

It is natural that if it emits strong magic power, it is easy to be detected. That is why Jin is so concerned about satellites.

"Well, it's quite difficult to make it stand perfectly still. ......"

Stopping relative to the earth's surface requires precise calculations and accurate measurements.

"Hmmm ......"

Jin wanted to establish landmarks not only for the target of the transition, but also for the calculation of the positions of aircraft and ships.

"Oh, by the way, for navigating a ship, not only a compass, but also, what did you call it, ...... let's see, ...... was it a quadrant or a s*xtant, ......."

Very roughly, the time of day and the position of the sun give the longitude, and the altitude of Polaris gives the latitude. If you know the latitude and longitude, you can find your position.

Gradually, the thoughts shift to a consideration of the navigational techniques of the ship they are building.

"Reiko, is there a North Star in this world?"

Jin did not know much about stars. Reiko contacts the old man with her built-in manacam and answers Jin's question.

"Yes. Yes, there is. There is a star with almost no error.

The earth's Polaris is actually off by less than one degree from the celestial north pole, so it appears to move in a slight circle, which accumulates to an error.

"I see. Then we can check its position at night with the North Star.

"No, you can see it in the daytime, too.

"What?"

Reiko's words came as a shock to Jin.

Reiko has far better eyesight than humans, as Jin, the creator, knows best. However, he had never thought that she could see stars even in the daytime.

It is said that a person with 6.0 or 7.0 eyesight can see stars even in the daytime, but Jin's eyesight is about 1.5, which is impossible.

However, he reconsidered that in this world where the air is cleaner than on Earth, Reiko's eyesight should be able to see the stars.

"Then, if we make a special measuring instrument, it is possible to calculate the position based on the time of day, the position of the sun, the position of the moon, and the position of Polaris. ......

The time is set as Horaijima Mean Time (HMT) with the institute on Horaijima as the longitude 0 degrees. Then we can measure the angle and calculate it.

"......" This should solve the problem of navigating the fleet.

I will send the idea I have just thought of to the old man and let him work out the details.

"Well, the problem is this way.

Jin changed his mind again, "The Horaijima fleet will be fine, but what about the ongoing project?

"A compass is a must. Then, we should use as few iron parts as possible in the ship.

Since most modern ships are made of iron, the compass is prone to go wrong. For this reason, a compass for ships is called a gyrocompass instead of a magnet.

However, since a gyro compass is too difficult to use at first, we will use a compass. He does not want to use steel parts for the compass as much as possible.

Just as he was thinking about this, Reinhardt and Erza arrived.

"Jin, what's wrong?　It's almost noon.

"Brother Jin, have you been lost in thought again?"

It was lunchtime before he knew it. Jin went to the common room with Erza and Erza. Lunch had arrived and everyone had already started eating except for Jin and the other three.

Jin also remembers that he was hungry, so he starts eating as soon as he sits down.

The menu for the day consisted of bread, fried freshwater prawns and vegetables in oil, sweet potatoes and fruit juice.

"...... Jin, how do you like it?　It's not polite to ask ......, is it?"

Reinhardt asked as we were finishing our meal and drinking more juice. The others all listen at once.

"Ah, yes. I've got a rough idea. Now we just have to make it."

"I knew you were good at this!"

Reinhardt's compliments were met with silent nods from those who had been listening. It seemed that everyone was convinced of Jin's abilities after just one day yesterday.

"We're pretty much finished here, too," said Reinhard. We are going to start talking about the interior this afternoon. Depending on the interior, there may be some minor changes to the hull.

"Yes, that's true. By the way, who is working on the model?"

Jin is alone in the other room working on the propulsor, so someone will have to be in charge.

"Who do you think?"

Reinhardt smiles mischievously. His eyes glanced over at Erza.

"...... Elsa?"

Erza nods her head. Her cheeks are slightly red.

"No, she is indeed Jin's number one student. She's even faster and more precise than I am. Everyone was impressed.

"Wow. ......."

Erza's face turned even more vermilion as Jin looked at her.

Meanwhile, the break time comes to an end. Jin first tells Reinhardt and Erza that he wants to use a compass, so he doesn't want to use steel parts as much as possible.

"I see, I understand. I will keep that in mind."

Reinhardt and Erza then headed for the afternoon meeting. Jin also returned to his role.

"Well, let's finish the propulsion system.

For Jin, it was quite simple.

If wind magic works on air molecules and water magic on water clusters, what about earth magic?

The answer is . From the molecular level to the rock level, anyway, it can be said that the earth attribute magic works on <>.

In other words, if you use <> type magic, you can generate propulsive force regardless of air, water, dust, and so on.

"But there are some drawbacks.

Jin modifies the prototype while muttering to himself.

"It's not very fuel-efficient. ......"

The amount of work done on the <> is lost when trying to use it on the air molecules. If you compare it to hauling a tennis ball in a large dump truck, you can imagine how wasteful it is.

"But you can improve it, can't you, father?"

Reiko interrupts Jin's soliloquy. She is so trusting of Jin that she says, "Of course, of course.

"Of course I can.

Jin smiles at her.

"All you have to do is add three magick formulas.

A judgment formula to determine the size of the object, a sorting formula to classify the object into three levels, and a control formula to change the force that works according to the size of the object.

In short, the idea is to apply the appropriate force to solids, liquids, and gases. This improves the efficiency to the point where it can be compared to the original wind magic propulsion system (wind thruster).

"He is my father after all!"

Hearing Reiko's praise, Jin rewrote the Magi Formula and reassembled the Wind Thruster. No, it is no longer a <.

"...... Well, let's call them <>."

Thus, the marine propulsion system, <>, is completed.

In the remaining time, Jin thinks of various ways to confirm the current position.

"Right!　We could bury the marker so deep that we can't dig it out!"

If not in the air, then deep in the ground.

"If the magic power pattern is just special and is so weak that it can barely be detected, no one will bother to dig it out.

In this way, Jin put his new ideas into practical use at intervals.