PHILOSOPHY VOICE Vol.02

Mr. Tetsuji Hoshino joined Mitsubishi Heavy Industries (MHI) in 1974 and he was involved in propeller and cavitation research and after a stay in South Korea, he now backs up Nakashima Propeller’s propulsion performance. He who has thoroughly pursued research and development of propellers on numerous occasions, what does he expect from Nakashima in the future? We also caught up with him about his unique hobby that straddles the sky, which started his research life in aeronautical engineering.

Q1. What was your initial job after you joined MHI as a new graduate?

I joined the company as a researcher, just as attention was beginning to focus on the problems of noise and hull vibration caused by stern fluctuating pressure induced by propeller cavitation, and my first research after joining the company was on stern fluctuating pressure induced by propeller cavitation. This eventually became the subject of my doctoral dissertation, and I was awarded a doctorate in engineering for "Estimation Methods for Fluctuating Pressure Induced by Propellers Generating Cavitation.“ I was also interested in propeller theory and read various domestic and international papers on propeller theory. Fortunately, MHI had an aircraft division, and the latest papers on aircraft from around the world were circulated to me, which I read frequently. Since propeller blade theory is basically the same as aircraft blade theory, many of these papers contained information that could be applied to ship propellers. Among them, an excellent wing theory called Quasi-Continuous Method (QCM) caught my attention, and I thought it could be applied to propellers. We used this theory to design propellers for our own ships and to estimate their performance. This propeller theory using QCM is still used in many research institutes in Japan and abroad.

Q2. How was your work experience in South Korea?

The Korean shipbuilding industry was booming at the time, and there were many young researchers who had just graduated from university working at the research institute where I worked. The first order of business was to instruct and train these young researchers. I also found it very rewarding to be involved in projects such as the development of propellers for ultra-large container ships (over 10,000 TEU) and biaxial ultra-large LNG carriers, which were not being built in Japan at the time.

Q3. After returning to Japan, what led you to join Nakashima?

Originally, before I left from the South Korea, I had received an offer through an acquaintance from an executive at Nakashima, what he invited "Would you like to come work with us after you retire?" At that time, I was strongly motivated to work overseas, so I declined the offer. However, eight years later, when they heard that I had returned to Japan, the same recruiter has reached out to me again, and that’s when I decided to join the company.

Q4. What do you think are Nakashima Propeller’s strengths?

First and foremost, the abundance of excellent personnel is a significant strength. Having designed and manufactured a wide variety of propulsion systems for various shipping companies, I believe each individual has acquired valuable know-how and experience. It's also positive that women are actively thriving in the company. Another strength I see is the high level of computer analysis capability. The ability to simulate with high-performance Computational Fluid Dynamics (CFD) without owning a test tank, and to guarantee performance in actual sea conditions, is quite rare and a considerable advantage.

Q5. What do you expect from Nakashima Propeller in the future?

I believe that Nakashima Propeller has multitype, talented employees, and the company is last bastion having a large marine propulsion manufacturing in Japan maritime industry. I hope that Nakashima Propeller will continue to survive as a propeller manufacturer, because propellers will continue to be the most efficient marine propulsion equipment in the future. I also hope that the company will continue to actively take on the challenge of automation and other innovative initiatives, since labor shortages have become a social issue in recent years.

Q6. Are there any lessons you would like to pass on to younger employees?

For instance, if there is a convenient tool or program in front of you, it's crucial not to take for granted that it is 100% correct. These tools all operate under certain assumptions and conditions, and they can cease to function properly if those are deviated from. Please make sure to carefully consider "how it works" before making any judgments. If you're involved in the development process, you'll be able to understand the mechanics from the ground up, master its use, and you might even come up with a better mechanism than what currently exists.

Q7. What are your hobbies?

My hobby is assembling and flying radio-controlled airplanes. I have been assembling and flying radio-controlled airplanes as part of my club activities since I was a student, and even now, when the weather permits, I visit the airfield in Nagasaki almost every weekend to fly radio-controlled airplanes with my airplane friends from various places. In the past, most airplanes were powered by engines, but recently, electric airplanes powered by motors and batteries have become the mainstream, partly due to moves to reduce environmental impact. While ships and cars move two-dimensionally on the surface of the water or ground, airplanes move freely in three dimensions, back and forth, left and right, up and down. This makes it more difficult to control, but I feel that this is the most interesting aspect of flying.