And this is only a short-term benefit, in the long run, after getting the technical blessing of the Han'e Shipyard, as long as the Endeavor factory does not die, it will continue to obtain technical improvements, so as to bring the existing shipbuilding technology to a new level at the same time, but also enhance the competitiveness of Endeavor in the same industry.

Compared with the benefits obtained by Endeavor Factory, what it pays is only the layered profit on the agreement, which may seem a lot at first glance, and also makes Endeavor Factory bear a lot of burden, but in the long run, this little investment is simply not worth mentioning, and even in the eyes of industry insiders, there is no difference with the price of cabbage.

This courage and vision can't even be praised by Dong Yimin, who can be called a "human spirit"!

Of course, praise in my heart is praise, but on the surface, Dong Yimin did not show the slightest, but after quietly listening to Meng Jianye's introduction, he nodded slightly, and then led the topic to the propeller: "So, your propeller is also designed and drawn by the Han'e Shipyard?"

"This is only the most basic cooperation, and in contrast, the research on which we are both involved is the most important thing in the cooperation between the two sides at this stage. Meng Jianye knew very well what Dong Yimin wanted to hear, so he simply didn't hide it, and threw out the dry goods directly.

Obviously, Dong Yimin was very interested in Meng Jianye's words, and asked with interest: "What is the subject?"

"One is to reduce the phenomenon of propeller cavitation, and reduce the damage of cavitation erosion to the propeller!"

"Oh?"

As soon as he heard this, Dong Yimin couldn't help but be a little stunned, others didn't know, but he, a scholar-type senior officer who had been trained by Soviet experts, understood.

Reducing and reducing the cavitation phenomenon and cavitation erosion of propellers has always been a frontier topic in marine propellers.

What is the cavitation phenomenon, simply put, when the pressure on the back of the propeller blade is lower than the water vaporization pressure at water temperature, the water flowing through the back of the blade can be vaporized at the water temperature, and the air dissolved in the water also escapes to form cavitation.

When the propeller diameter, pitch and rotation speed are larger and the advance speed is smaller, the half-flow speed and angle of attack are larger, and the pressure drop on the back of the blade is greater, resulting in cavitation.

In short, the larger and faster the ship is, the greater the load of the propeller it is equipped with, and the more serious the cavitation phenomenon will be.

As for cavitation erosion, after the cavitation phenomenon occurs, when the cavitation generated in the local area behind the propeller blade is washed into the higher pressure area by the water flow, the water vapor pressure in the cavitation cannot support the external pressure and collapses rapidly.

At the moment of cavitation collapse, the surrounding water flow rushes to the surface of the blade at high speed, forming a shock wave of up to thousands of atmospheres in the local area.

Don't underestimate the cavitation phenomenon and cavitation erosion of the propeller, which not only affects the service life of the propeller, but also is the main source of underwater noise of the ship, because the collapse of the cavitation is often accompanied by irrepressible noise, which makes the underwater acoustic index of the ship remain high.

If this is a civilian ship, it will be fatal, because it is tantamount to revealing its whereabouts, so that it will be quickly discovered and eliminated by the enemy.

However, there are only two best ways to solve the propeller cavitation phenomenon and cavitation erosion, one is to make a fuss about the shape of the blade, for example, the pressure distribution of the round-back section is more uniform than that of the airfoil, and the pressure of the blade is less than that of the narrow blade.

Another way is to increase the number of blades, such as five-blade, six-blade or even seven-bladed blades.

However, whether it is to control the shape of the blade or increase the number of blades, it needs to be completed with extremely high machining accuracy, otherwise once the accuracy is not well controlled, it may lead to the premature generation of cavitation, which is extremely dangerous for the propeller.

This is the biggest difficulty in reducing the propeller and reducing the cavitation phenomenon and cavitation erosion of the propeller.

Dong Yimin was obviously clear about the technical difficulties of the propeller, so he raised his eyes and looked at the Soviet-made propeller special processing machine tools in the workshop, and then continued to ask: "How is the progress?"

"We are now using the four-bladed paddle to do theoretical mathematical model tests, and it will not be long before trial production will start in the factory. ”

Dong Yimin hummed thoughtfully after hearing this, and did not continue to ask, but changed his words: "What about the other one?"

"The other is the research of materials, for example, the noise and shock absorbing materials that are in demand are relatively large, vermiculite slabs, slag wool, slag boards, these materials not only have very good sound insulation effect, but also fire and moisture resistance; ”

Speaking of materials, Meng Jianye was not as calm as he was just now, his brows were furrowed, and his tone became quite sad.

No matter how complex the propeller is, there are people, theories, and equipment, how can it be made, it is nothing more than a matter of time, but the material is not what you want to do, it involves a lot of basic science, but Meng Jianye is also a layman in this regard, so he can only promote the development of materials science within the scope of his ability.

The topic of joint research on noise reduction materials with the Han-E Shipbuilding Institute is one, and the sincere complaint to Dong Yimin is naturally another.

Dong Yimin couldn't hear Meng Jianye's complaints, so he immediately didn't say anything, and asked straight to the point: "Did you encounter any difficulties?"

"Of course, the most important thing is experience, if there are one or two material samples for analysis, the progress of the Han'e Shipyard will be faster. Meng Jianye was not ambiguous, and said all the difficulties he could think of in one sentence.

Dong Yimin just frowned, but didn't say anything, but asked the entourage around him to write down the materials, and then raised his head and looked at Meng Jianye and Jiao Dalin in front of him, and suddenly asked: "If you are asked to build a ship with a displacement of about 600 tons, how long will it take you?"

"If it's just a simple renovation, our factory should be able to complete it in three months to six months. Jiao Dalin replied very simply, but Dong Yimin shook his head: "If it is a simple renovation, what are you going to do in the shipyard?

As soon as these words came out, Jiao Dalin opened his mouth but did not dare to continue to respond, but lowered his head and discussed with Meng Jianye beside him, and then turned around and said: "Then it depends on whether the materials are sufficient, as long as the materials are enough, our factory should be fine within three months!"

"Okay! I remember your words!"

Dong Yimin replied with satisfaction, then beckoned to the entourage around him and strode towards the outside of the propeller manufacturing workshop......