MTL - Warship of Great Power-Chapter 3 Two external engines

  Chapter 3 Two external engines

  The speed is not enough for power, which is applicable to any means of transportation. For example, on an aircraft, there is a saying: as long as the engine is strong, a brick can fly into the sky!

  So, for a reborn Qin Tao, who has decades of experience in ship design, it is definitely quite simple to increase the speed of this speedboat with a displacement of about ten tons.

  The target customer is the customs inspection, and they require the faster the speed, the better, so what else is there to say, the engine!

  Especially the speedboat in front of me uses an external engine, which makes it even simpler. If one is not enough, two engines are installed, and two engines are not enough, three engines are installed. It is simple and easy.

   The smuggling boats at sea, needless to say three, have brought this layout to the extreme, and Qin Tao has seen all of them with six engines.

There are two arrangements for the engines of ships. Large ships are arranged inside the hull and drive the propeller at the tail through the transmission shaft. If the power of one engine is not enough, two or even four engines may be used. It can not only drive different propellers, but also work together online.

Small boats don’t need to be so troublesome. Just put the engine, drive shaft, and propeller together and put them on the stern. When needed, flip the device down to provide power. When you arrive at the dock, flip the device back. Avoid long-term immersion in water to cause loss.

  In the past, Mingzhou Shipyard produced fishing boats, at least with a displacement of hundreds of tons, so the engine was inside the hull. What is being built now is a speedboat, using blueprints purchased from island countries, and a plan with an external engine.

  For the workers of Mingzhou Shipyard, this is the first time they have come into contact with this power output method. It is okay to follow the example, but it is impossible for them to innovate.

  However, in the eyes of Qin Tao, a traveler, it is a piece of cake.

"Power? Change to a high-power engine? Our factory has no funds to purchase a new engine. If we used a domestic engine at that time, we could save a lot of money. However, Director Song insisted on purchasing engines from island countries." What a waste of money!" Zhao Changshui sighed again.

   At this time, Qin Tao pointed to the Yamaha F100 external engine at the rear of the speedboat and said, "How many such engines have we imported?"

"I bought ten units in total, five were used on the ship, and five were kept in the warehouse. When I bought them, ten units could be given the wholesale price, and one was 95,000. These engines alone cost nearly a hundred Wan!"

"That's right, the factory ran out of money at that time. The big liar Song mortgaged the assets of the factory to the bank and borrowed money from the bank. Now, the customs don't want these ships. Seeing that the repayment date is coming, the bank wants to seize us. If the big liar Song doesn't run away, the big guy must beat him up to vent his anger!"

  Everyone became angry again.

  Qin Tao nodded: "Well, that's easy to say, take out the engine in the warehouse, and put two engines on the back of this speedboat!"

What? Everyone was stunned.

   "For a ship with a displacement of ten tons, two 100-horsepower engines drive together, that is 200 horsepower. Now, are you afraid that the customs will be dissatisfied?" Qin Tao said

  Qin Baoshan frowned there: "Isn't that appropriate?"

   "Why is it inappropriate? It is not difficult to modify an engine pylon." Qin Tao was a little curious.

   "One engine weighs more than 100 kilograms, two engines weigh more than 200 kilograms. In this way, the center of gravity of the ship will change, the bow will be upturned, and high-speed navigation will be unstable."

  When Qin Baoshan heard his father say this, he almost gave him a thumbs up.

  Although Dad has a high school education, his teaching level in the 1950s and 1960s was really not good. Five years of primary school, two years of junior high school, and two years of high school, how much knowledge can one learn? Not to mention that Dad only went to the first year of high school, and in the second year of high school, he entered the shipyard.

  In that era, schools were run in accordance with the spirit of the "May 7th" directive: when schools were opened, students not only had to study literature, but also to study engineering, agriculture, and military... So, even if high school education was popularized, the cultural level...

  Dad is a special case. He loves to learn and use his brain. Otherwise, he would not have made his mark after entering the shipyard, worked hard for decades, and became the director of the factory.

   Now, Qin Tao said that two engines should be installed outside, and the father immediately brought up the risk of this kind of installation.

"Yes, of course the bow of the boat will be upturned. In fact, we just need to tilt the bow so that the speed can be increased." Qin Tao said: "According to specific calculations, a 100-horsepower engine can drive less than ten Tons of ships should be able to run up to 30 knots, but the existing speedboat tests are not optimistic, why is that?"

   "High resistance?" Qin Baoshan's eyes sparkled.

Aluminum is replaced by steel, and the weight of the ship increases. Therefore, if the original design of the Yamaha marine engine placed at the stern can lift the bow by three degrees, it cannot be lifted at one time. The contact area between the ship and the water surface is large, so it can run The resistance also becomes larger. This is why current speedboats cannot reach the design speed.

If a ship wants to speed up, it is facing a very complicated hydrodynamic problem. In simple terms, when the speed is low, the resistance is proportional to the speed. After the speed exceeds 20 knots, the resistance is the square of the speed Proportional, at thirty knots, the resistance will be proportional to the cube of the speed. Therefore, the required power will also increase geometrically.

If no other changes are made, even a 100-horsepower engine can drive the speedboat to a speed of 30 knots, and a 200-horsepower engine can only drive the boat to a speed of 40 knots at most. To design indicators, other changes have to be made.

  The weight of the two engines pries up the bow of the ship, so that the area in contact with the water surface is reduced, greatly reducing the resistance, and allowing the ship to increase to the predetermined speed.

   "Will the ship be unstable?" Qin Baoshan was full of worries again.

"Unstable? How is it possible? The weight of the hull is increased by replacing aluminum with steel, so the stability should be better. If converted according to the ratio, the three engines are pressed on the back, and it has just reached the degree of inclination of the aluminum hull." Qin Tao said: "So, don't worry, it's absolutely safe."

   While speaking, someone has already pushed the engine out with a small cart.

  Qin Tao directed a few workers to work quickly, dismantled the original engine, replaced the position of the bracket, welded the second bracket, and installed the engine. The work was done in an hour.

   "There is no champagne for a grand launching ceremony." Qin Tao said: "Let's try it like this!"

  The berth is very simple, there are two rails under the speedboat, and everyone can push the speedboat directly to send the speedboat into the water.

   With a splash, the water splashed, and Qin Tao couldn't wait to jump into the cockpit: "I'll try it!"

  (end of this chapter)