I’m Scott Reichow. I manage Mercury Racing’s propeller department (see my previous post, Bravo for Outboards? YES!). Working in performance boating is exciting: It’s fast paced. Propulsion systems and hull designs are in continual evolution. Our customers are generally astute, technically oriented and often quite colorful characters. We’re all performance freaks! We’re all continually learning. That’s what makes my job so much fun!
If you are like me, your first boating experiences were in lower horsepower boats used primarily for family recreation, fishing, skiing, wake boarding, or general cruising. And like me, your boating experiences and knowledge have evolved through time.
When working with high-end performance boats and experienced customers, one tends to assume people have basic product knowledge. However, a propeller is complicated. Because our backgrounds vary widely, our levels of understanding vary widely, too. So, we’ll revisit the basics and then dive deeper on propeller form, fit and function.
Back in the 1980s, Quicksilver Accessories published a book entitled, Everything You Need to Know About Propellers. It was a bible for folks like me who were learning about a very complicated and critical component that is used in diverse applications and environments. Much of the information I will be sharing is from the fourth edition of this knowledge guide.
(Note, the information and cut-a-way photo in Everything You Need to Know…, Figure 2-4, is dated. Many Mercury Racing propellers now feature removable solid hubs.)
Anyone who has shopped for a propeller has been exposed to terms describing the various design functions. I remember when props evolved from two to three blade designs. And when replacing the prop on the family runabout, all you needed to know was the diameter and pitch. In the go-fast world of performance boating, diameter and pitch are important, but many other factors come into consideration as well. Its all about efficiency. Diameter, pitch, rake, cup, rotation, number of blades, blade thickness, blade contour, skew, ventilation, cavitation, elevation and angle of attack all come into play when propping a boat for maximum performance and efficiency.
I’ll get deeper into these facets of propeller design that affect boat performance in my next post, Prop School – Part 2: Terminology.