Yamaha boat propellors handcrafted in Indianapolis eastside plant

Props at Yamaha's prop plant in Indianapolis are individually handcrafted, ground and polished.

Each prop has its own mold.

        Most boaters don’t think much about their motor’s propeller. As long as the prop turns and provides the speed they want for fishing, skiing or joy riding, they are happy.

Some may recognize there is a difference between some props used for skiing and others for enjoying a ride down the river or across the lake. However, most people use the same prop for both and rarely think about the prop unless they hit an object such as a stump, log or rock.

However, props play a major role in boat performance.

I never thought much about props until a thief decided he needed my stainless steel prop more than me. A friend suggested I could order one from the internet. I quickly learned that there was no one prop for my old 60-horse motor. There were significant numbers available for my motor, depending on how I used it and several other factors.

One key factor is pitch. That’s the distance (in inches) a particular prop would theoretically travel in one full revolution, as if traveling through a solid. 

A lower pitch will have greater acceleration and “pushing power” but a lower top speed, while a higher pitch prop will provide less acceleration, but a greater potential for higher top speeds.

After scratching my head several times, this old guy who has trouble changing light bulbs, went to a dealer to obtain a prop. At the time, it seemed rather expensive, 

Recently, I learned why props cost more than I anticipated, when I by chance received an invitation to visit Yamaha’s Precession Propeller Industries in Indianapolis, IN.

Frankly, I figured making a prop not much different than molding a candle. I thought someone would pour some hot stuff into a mold, let it cool a bit, and trim off the excess, and polish. And there, you would have a product.

I had no idea how much craftsmanship, labor and personal attention goes into every Yamaha prop.

Craftsmen and women make an individual mold for every prop. The individual wax molds are made in rooms with controlled temperature and humidity. Each prop is cast in the company’s foundry, and is ground and polished many times. It is inspected during every step of the process.

The average prop takes 15-18 days from start to finished product. Some take longer. And on average, a prop requires 100-110 man hours.

Each prop has a serial number cast on it, and plant officials have a detailed record of the building of the prop. They know when it was cast and which employee worked on each step of the process.

Jim Bough started the business in 1981 by developing props for bass fishermen who wanted top performance from their boats and motors.

Yamaha purchased the company to provide propellers for their motors, and also now makes models for other manufacturers. In addition, the company makes a limited number of props for other kinds of equipment for the food and drug industries.

Today, the company is approaching 100 employees and crafts about 40,000 props per year. It hopes to double its prop making capacity to nearly 80,000 over the next three years.

Although I don’t fully understand the stainless steel prop crafting process, I have a much greater appreciation of how they are built and what they can do for boat performance.

And on my boat, I now keep either a lock on the prop, or remove it when the boat is stored.