On the evening of the day of Marcia's victory, a victory party was held.

The place of the party was the home and office next to Marcia's workshop.

The guest of honor was, of course, Marusia. Next to her is her father, Rodrigo, with a smiling face. And his employees, Bacchus and Jeremy, are sitting in the corner with nervous faces.

"Congratulations, Marcia!

"Thank you, Elsa."

"Congratulations, Marcia."

"Thank you, Jin."

"Congratulations, Marcia!"

"Thank you, Hannah."

"Congratulations, Marcia!"

"Thank you, Licia."

"Marcia, that was wonderful!"

"Marcia, that was amazing."

"......, why are there a prince and a princess here?"

Marcia's forehead was covered in cold sweat. Bacchus and Jeremy, commoners by nature, were shrinking.

"Don't worry about them, they're just ninjas."

"Yes, yes. I'm only here because I'm a friend of Jin's."

"Even if you say don't worry about it, ......"

"By the way, His Highness Ernesto paid for the entire victory party."

Erza reveals the backstory.

"What?

You should use the prize money for yourself.

"That's right. Celebrations are for those who celebrate, not for those who are celebrated.

Prince Ernest and Princess Rieschen seem to understand.

"Hey, hey, let's eat!"

Hannah's right.

They toast to their newfound good mood.

Cheers!

Cheers!

Hannah drinks Citran juice and the rest of us have sparkling wine.

"Wow!　This is very smooth!

However, the alcohol content is so low that Princess Rieschen can drink it ......, or rather, the royal family sometimes drinks wine at the age of 12.

"It's a specialty of the western part of the Kingdom of Elias," he said.

Prince Ernest had gathered this information in advance.

"It's delicious.

Elsa seemed to like it too.

"It's sweet and pleasant on the palate.

Jin also found it an easy-drinking wine. I thought about giving it to Reinhardt, a wine connoisseur, as a souvenir.

"It's delicious. Maybe it's good for beginners.

Licia was also smacking her lips.

After that, we had a chat while eating.

Not only in the Kingdom of Klein, but also in the Kingdom of Egelea, it is said that chatting while eating is bad manners, but when in Rome, do as the Romans do, and in the southern part of the Kingdom of Elias, they eat while chatting happily.

But this is only the case when they are close to each other and at an auspicious occasion such as a celebration.

"I came to the Kingdom of Elias to learn about ships.

I followed Master Nesto.

"That's why I was wondering if you would allow me to visit tomorrow."

"I know Jin, and above all, he's His Highness, so ...... I've accepted!"

Thank you, Marcia.

"But it sounds like you have a lot of work to do on the practical application of the screw.

"Yes, I was fine with the outboard motor."

"That's right, Master Jin. This time, in order to make it golem-driven, we extended the shaft and brought it inside the ship. ......"

"That's why there was vibration and ...... not enough strength."

Jin has begun to analyze the trouble. Marcia and Rodrigo are also enthusiastic, Elsa and Hannah laugh and say, "Here we go again," while Licia can't keep up and her eyes are black and white.

"Well, this inquisitive mind is a djinn after all."

"Yes, it is. ......"

Prince Ernest and Princess Rieschen looked enlightened.

"This time, we paid the most attention to the waterproofing of the shaft. It was not strong enough. ......"

Rodrigo explains how it happened.

The pipe through which the screw shaft passes is called a stanch tube, and there is inevitably a gap between the stanch tube and the shaft, through which water can enter the vessel.

To prevent this, various methods have been devised, ranging from a simple method of filling the stanch tube with grease to advanced sealing methods.

"I tried something called a grease box."

"Heh, ...... that's great."

A grease box, or grease box, is a method of inserting a box-like component filled with grease where the screw shaft protrudes into the vessel from the stanch tube.

The grease box is used to insulate the stanchion from any water that rises up from inside the stanchion.

This method is relatively used in ship models.

In this case, it is necessary to use rust-resistant materials for the stun tube and screw shaft, and Rodrigo used light silver.

Rodrigo used light silver, but the shaft diameter was too small because of its high cost, and the lack of strength was a mistake.

"I will use the prize money to buy light silver and make a more complete boat.

Rodrigo declared enthusiastically.

"Marcia, how is your store going?"

As Jin was talking with Rodrigo, Elsa spoke to Marcia.

"Yes, very well!　The trimaran is easy to maneuver, and the balance of the power installation is good.

They are developing the boat with the concept of using as little magic engine as possible.

In this case, a golem is rowing the boat, but it can also be rowed by a human. However, in that case, the speed and cruising range would be extremely reduced. .......

"The fact that it can run even if it runs out of mana is an advantage, isn't it?

"Indeed, it is."

Unlike Jin, the general public does not have the backup of Horaijima, so such a characteristic is important.

"By the way, what does the prince want to know ......?"

"Haha, you can use the same tone as everyone else while you're here. ...... Well, I'd like to build a 20-meter class transport ship eventually, and I'd like to learn a lot of things for that."

"Oh, I see. Well, in that case, I might as well start with the basics of the ship.

"Yes, please!"

Marcia and Prince Ernest seem to be getting to know each other.

Prince Ernest was originally interested in making things, especially golems, so he was able to follow the conversation.

"I'll come back tomorrow for more details.

"Yes, yes."

Marcia was a little surprised by his vitality.

"I want to know more about the ship, too.

"Well, Hannah, if you stay with me and stay close to Nest-sama, you will be able to hear many things.

"Oh, yes!　Thank you, princess!

Princess Rieschen looks a little confused when Hannah says this to her.

"Well, I hope you don't call me 'princess' in an informal setting."

"Well, then, can I call you ...... Ries, big sister?"

Princess Rieschen's face lit up at this suggestion.

"Oh, oh, that's good!　No, you can call me that!"

Princess Rieschen, the youngest, was happy to be called by Hannah.