Sword, Magic and Academic Society

Vol. 1 - Ch. 97 - Sail (3)

They were really like hounds who didn't know when to stop... So I thought as I saw them circling their second dead comrade once again.

No, it was like the death of their comrade just fueled their obstinacy even more.

"Dan! Turn on the magical tools now."

I passed my instruction. If they were going to be mad either way, might as well turn on the sound that grated on their nerves to make them lose their cool. They used sounds for communication, so I was betting on the possibility that the sound from the magical tool would break their communication and cause them to act more recklessly.

It really did work out in my favor. A seemingly juvenile White-tailed Orca, which was around 6m in length, went straight for the rear deck. Its fin part breaking out of the water was proof it was losing its calm.

Once it was close to the ship and showed its head out of the water's surface, I fired three iron arrows and put an end to its life.

Three more to go.

From there, the White-tailed Orcas seemingly gave up on tackling our ship, but they also didn't show signs of letting up, constantly keeping a certain distance.

There were also moments when their leader, the biggest of them all, would spray water on us using water magic to irritate us. Fortunately, it perhaps couldn't use the magic in succession which gave Gutx and the others time to drain the water.

I discussed with Dan to see if he had any ideas as to what they were up to.

"...What're they trying to do?... Or is it just simple harassment now?"

"Hmm, it's hard to say if they've given up. Are they eyeing an opportunity to go all out, or maybe there's something up ahead that would help---"

Dan spoke his guess but the answer showed itself before he could complete his words.

What should have been--- at least, that was what it looked like --- the only water-element Orca nearly 10m in length suddenly increased to four. They surrounded the ship from a distance from all four directions and blasted their water spray at once.

......Now we were truly in a perilous situation. The rest of the crew wouldn't be able to drain the ship fast enough if the Orcas continued to spray water at this pace and this would lead to the sinking of the ship.

However, we had a bigger problem before we could even worry about that. The water that the Orcas were spraying from left and right was seriously hindering the operation of the sails.

The sails lose the wind current when a vertical ship suddenly changes course abruptly, resulting in a drop in speed. Dan was correcting the ship's direction whenever the main sail turned in the opposite direction after being struck by water magic. But it was only for now, even Dan would be unable to stop the speed from dropping if he kept readjusting our direction.

On the other hand, the attribute-less variant of the Orcas had started to jump a bit away from the ship, seemingly boasting of their victory.

This might be the time... I thought of using my MacAquate arrows to shoot them now, but I then shook my head. There was a whole swarm of 17 Orcas after us, aside from that huge leader.  I could shoot down the four but that would hardly relieve us from this predicament, and we didn't have much time.

"---A leap of faith then. I'm going to use wing magic! Match with my timing!"

I wasn't sure how it would work but I was going to try if I could use wind magic to accelerate the ship.

But the wind was already coming from the rear-diagonal direction, so I was using the best of my mana operating skills to blow the wind at 15m/s--- or 54 km/h when converted.

Even if I could create a stronger wind current, it would be impossible to circulate all the mana released outside back to my body. I think my mana reserve would dry up in 3 minutes if I increase the wind speed to, for example, 30 m/s while doing my best to reserve mana. (T/N - Just explaining in case of doubt - MC can use mana compression during activities to absorb mana even when using magic for any purpose, which means he can keep his mana bar infinitely 'til his stamina runs out or unless he uses some technique that consumes more mana than what he could take in.)

But we're still being checkmated.

We absolutely were in dire need of a plan to somehow break through this siege and enter the inland region.

I wracked my mind for a solution while turning the direction of my wind magic at the sail.

???

I guess there really was no such thing as a surefire plan.

The sail started to show erratic movements the instant the sails were filled with wind which resulted in an adverse effect--- the ship's speed dropped down.

Dan instantly pulled on the line and adjusted the sail while calling out in protest.

"Hey!"

"I'm thinking!"

......It was indeed a gamble but I didn't expect the plan to actually backfire.

Right, what was the principle at which a yacht moves?... Hrg, I for sure had seen it somewhere but I couldn't recall it exactly. Damn, why were you so idiot, earthling-me? My current self could easily remember thousands of books!

My back was drenched in cold sweat but my mind was still clear. It looked like my training until now has bore fruit. Oh, right. My fingers were all steady when I was shooting arrows despite the do-or-die situation.

I could still recall how nervous I was back when we encountered the Greateus Snake.

I was surprised at myself too. To think I still had the mental capacity in a corner of my mind to run through these monologues while wracking my brain for an idea.

To feel the flow of wind, I tried circulating wind magic at about 15 m/s, as if I wanted to become one with the wind that pushed the sails. It was this moment that suddenly sparked my memory.

"Ah, so that's it! Bernoulli's theorem!"

"Huh?! Berno--- what?!"

Dan raised a bewildered voice in response to my shout. Unfortunately, there was no time to answer.

I controlled my mana and slowly weakened the wind going past the ship's interior.

???

The ship suddenly picked up speed in that instant. Meanwhile, I continued to further rein in the speed of the wind.

Honestly, the ship had actually sped up to a comical level. Then Dan's yell followed.

"Hey, hey, hey Ren! The heel is getting too hard to control! We're going to go capsize! Gutx! Immediately move all the Deareise to the port side. Put as much weight as you can on the left!"

The heel referred to when a ship was moving inclined in a headwind direction.

Ships with engines could advance in a straight line but vertical ships moved diagonally, in the direction the sail was turning.

Dan meant the lateral recovery force was unable to catch up with the ship's pace, strongly focused on the diagonal direction.

Gutx and the others hurriedly moved the cargo to the left side, where the ship was almost lifted into the air, and centered the weight on that side as much as possible to keep the ship's advancement straight.

After seeing that, I further weakened the wind passing the ship slightly and increased our speed.

???

Bernoulli's theorem--- the principle behind how planes could fly in the sky or yachts could head in an upwind direction.

The wind becomes faster than the opposite side when passing over the top of the main wings of an airplane--- or curved part in the case of a yacht.

What happens then is that the pressure on the faster side decreases, creating a lifting force that pulls in that direction.

The lifting force generated due to the difference in atmospheric pressure was far stronger than the wind's suppressive force--- after all, that was how those huge passenger planes could take off.

Similarly, yachts were able to cross the upwind direction utilizing the same lifting force.

Cutting my rambling short, what I did was weaken the wind current passing by the sails, creating a contrast with the wind flowing outside which resulted in the increased lifting force.

The key point here was 'de-acceleration.'

Bernoulli's theorem, which is based on the conservation of energy principle, however, was unable to be carried out when energy acted fluidly from the outside.

That said, I wouldn't know if the de-acceleration of the wind with magic meant converting kinetic energy into pressure (density), or maybe it would stop due to the outside energy.

I had taken the mana conversion theory and fundamental laws of motion into account to reach this conclusion but it was an armchair interpretation at best.

???

All I did was lower the speed of the wind current, which in turn increased the influence of the wind current working outside the ship. That was all I knew. I really needed to experiment more if I wanted to get to the details.

But that said, it also finally clicked on why I failed earlier. The reason why the sails had fluttered violently was because I had done the opposite.

In fact, this technique was our silver bullet in this situation. I didn't strain my mana much and as long as the wind flowed like this, we could semi-permanently keep this speed up. According to my guess, our current speed was 30 km/h.

White-tailed Orca's cruising speed was 15 km/h so I bet they must have been desperate now. The fact that they weren't using water magic again while chasing after us was the best proof.

Honestly, I was surprised. The White-tailed Orcas were like some kind of mavericks on a mission as they kept their chase with no intention of stopping.

It was then that Dan raised his voice from the cockpit with an anxious expression.

"Oi, Ren! We need to somehow make a turn now or we would crash into land! You can do it again, right...? You will, right!?"

With my best smug face, I gave a thumbs up to Dan.

T/N - ......This chapter was truly fitting of fantasy and academia title. Remember guys, be sure to focus on your class, who know when you might isekaid. On the side note, MC at the end must be like 'payback time.'

E/N - I'll be honest with you, I have no clue if the stuff the author wrote about the Bernoulli principle is correct or not. So take it with a grain of salt and do your own research on it if you're interested. I tried to google it but Physics was like my worst subject in school and I understood jack shi--- well you get what I'm saying. ?