What is the speed of 7 knots? That's 7 knots per hour. And every nautical mile is 1.852 kilometers, that is, the speed of 7 knots is 12.96 kilometers per hour......

What the hell is this, even a bicycle can reach a speed of 20 kilometers per hour on the road, which is also a bit of speed?

However, this is also the case with Marin, a person who has seen the world. In the eyes of others, 7 knots is truly remarkable. At least, in river boats, it's pretty fast. You must know that in this era, ships at sea, because of the strong sea breeze, could only run at a speed of 10 knots at most with a full sail and a tailwind. Only a long and narrow speedboat can run at a high speed of 12 knots.

But it was at sea, and the wind was strong. And inland, the wind is not even as strong as in the Mediterranean. So, river boats are generally slow. Even with the use of galleys, because of the limited strength of man, it is not possible to row heavy oars to fly, and can only row the boat at a speed of five or six knots. It's not that you can't draw a speed of 7 knots, but it's usually an empty boat, and the oarsmen are paddling desperately. However, this kind of paddle can't last, after all, people can't do it at high speeds for a long time. So, in general, it is difficult for a galley to reach a speed of 7 knots.

On the other hand, the Calais, with the blessing of the downwind is the sail power, and the oarsmen paddle together, they can reach speeds of 7 knots. But in general, oarsmen also need to conserve their stamina and not break out often. Such speed can only be achieved when fleeing or chasing in naval battles.

Therefore, in the face of the "speedboat" that can steadily sail at a speed of 7 knots, everyone else is amazed, thinking that it is simply a miracle sent by God.

"Is that a miracle? I really didn't know it......" Marin rolled his eyes and decided to make a big move.

So he called Leonardo da Vinci and commanded:

"How many sets of diesel engines and propeller systems do you have?"

Leonardo da Vinci replied:

"10 sets, all of which are qualified diesel engines that my students and I have improved and screened."

In fact, the craftsmen of the North Sea Kingdom built more than 100 12-horsepower single-cylinder diesel engines. However, due to the manufacturing process and various improper operation reasons, in the end, Leonardo da Vinci and his mechanical college students only selected 10 qualified products. As for the propeller system, it is nothing, more than 20 sets of transmission rods and propeller blades made of nickel steel, 12 sets are qualified, almost half of the pass rate.

"10 sets, right...... Hehe, Ada, I'll teach you something fun to make the boat faster! ”

Leonardo da Vinci was confused, and Marin suddenly asked again:

"Ada, do you know 'Da Fei'?"

"Big Fly? Who is it? Leonardo da Vinci was confused.

"Alas, it seems that he is not a traverser, and he doesn't know the ...... of 'Da Fei'"

So, what is "Big Fly"? In fact, it is a kind of smuggling speedboat. The speed of an ordinary speedboat is only thirty or forty kilometers per hour. However, as a smuggling speedboat, in order to escape the interception of the anti-smuggling boat, the "big fly" will often modify the speedboat, making the speedboat very high.

The modification is also very simple - six or even seven 250 hp marine hangers are mounted side by side at the stern of the speedboat. In this way, the 6 boat hang-ups work together to push the speed of the speedboat to a very high level.

Generally speaking, a "big fly" with a car or more than 300 boxes of cigarettes can run at a speed of more than 90 kilometers per hour. Because of the resistance of the water during high-speed sailing, the speedboat often breaks through the water barrier and "flies" on the water, so it is also called "big fly".

The speed of the big flight is too fast, and the speed of more than 90 kilometers per hour can be carried on the high speed even on land. The speed of anti-smuggling ships at sea is generally about 60 kilometers per hour, and the maximum speed is 80 kilometers per hour. When encountering this kind of unreasonable and fast "big fly", there is really nothing to do.

However, later Huaxia had money, and the customs department had sufficient funds from above, so it directly changed shotguns and equipped helicopters...... Nima, no matter how fast you "fly", can you be faster than an airplane? Then, "Da Fei" was restrained by "True Flying (Machine)......

Of course, in this era, everyone has not seen the power of "Da Fei". Marin smiled mysteriously and began to instruct Leonardo da Vinci and his mechanical students to modify the hull. A small boat of more than ten tons, with 4 12-horsepower single-cylinder diesel engines directly hung on the stern...... This is also due to the fact that the boat is too small, and the diesel engine needs to be started by crank handle, so it is necessary to free up space. Otherwise, Marlin plans to load 6 ...... at once

After the four diesel engines were installed, Marin ordered the four mechanical students to shake the shaker handle together and start the diesel engine. Then, the gear ...... Of course, there is only one gear, and the other is neutral......

After putting up gear together, the speedboat rushed out quickly like an arrow off the string. The rope knots and empty barrels used to measure the speed were also quickly dragged away......

Leonardo da Vinci and a group of mechanical students went directly to Sparta......

"What's the speed?" After a while, seeing that the rope and the empty bucket had been pulled away, he began to inquire about the records.

"Probably...... Up to 18 knots? ”

"How much?" Leonardo da Vinci thought he had misheard, snatched the notebook, and looked at it—no problem, v. 18......

At this time, Marin realized that something was wrong and ordered-

"Quick, ride a horse to catch up, and give the order to stop the ship with a horn!"

This small river for the mechanical department to test the speed of the ship is only a dozen kilometers long, but it cannot withstand the "wild running" of this boat......

As a result, it was still a step too late, and the "speedboat" rushed to the beach at the end of the river at a high speed of 18 knots. The four mechanical students who were in charge of driving the ship were all injured, but fortunately none of them were too serious. But the hull of the wooden boat was directly damaged, and even the diesel engine was also broken twice......

After Leonardo da Vinci comforted the injured students and took them to the hospital, he danced with emotion:

"If all the ships are equipped with this kind of power, who will be able to catch up with the ships of the North Sea Country?"

Marin poured cold water on him:

"Don't dream, Ada, ...... diesel is not enough"

Indeed, at present, the North Sea countries can only import oil from the Galician Valley in Poland, and will soon receive oil from the pit on Taiwan Island, and can also import oil from Persia......

However, even so, oil production is low......

Oil production in the Galician valley is low, at only one or two barrels per day, and that's after Marin's big investment. The extent of the pit has been determined, but it is still being explored. Moreover, it is necessary to wait until the Zhuo tube well is opened before mass production can begin.

On the Persian side, according to the information returned, the Baku region over there can indeed produce hundreds of ships of oil every year, but Marin can only buy dozens of ships. Because the Middle East is also in need of oil for cattle and sheep to treat skin diseases......

Therefore, on the one hand, Marin needs to vigorously develop new oil fields, and on the other hand, he plans to discuss with the Persian side and take the initiative to invest in the development of the Baku oil field and drill a few more deep wells in order to obtain more oil.

Only with enough oil can this kind of magic reform "big fly" be really put into use......

However, to say that it is "Da Fei" is really an insult to the name of "Da Fei". Because, the speed of this ship is too low......

18 knots looks bluffing, and its actual speed is only 33.3 kilometers per hour, which is a little faster than the electric bicycle after the speed limit. Of course, this is also related to the fact that the speed of the diesel engine is not as fast as that of the gasoline engine.

In addition, this diesel engine as an on-hook engine is also too cold......

The real "big fly" of people is hung with 250 horsepower imported marine hang-ups, and the power is extremely strong. And Marlin, the weak chicken version of the magic change, is hung with a 12-horsepower single-cylinder diesel engine, and the single power is only less than one-twentieth of others......

Therefore, people's real "big fly" can "fly" on the sea. And the weak chicken version of the demon made by Marin can only rush in the inland river......

However, the speed of 18 knots did shock the natives of this era. Even Leonardo da Vinci, a peerless genius, was a little frightened. If they were to evaluate this "weak chicken version of the Demon Change", they would definitely agree with the title of "Big Fly". Because, in the eyes of these natives, a speed of 18 knots is equivalent to "flying......

(I guessed the speed of 18 knots, but I haven't tried it, mainly because I don't have the conditions to test)