We are independent & ad-supported. We may earn a commission for purchases made through our links.
Advertiser Disclosure
Our website is an independent, advertising-supported platform. We provide our content free of charge to our readers, and to keep it that way, we rely on revenue generated through advertisements and affiliate partnerships. This means that when you click on certain links on our site and make a purchase, we may earn a commission. Learn more.
How We Make Money
We sustain our operations through affiliate commissions and advertising. If you click on an affiliate link and make a purchase, we may receive a commission from the merchant at no additional cost to you. We also display advertisements on our website, which help generate revenue to support our work and keep our content free for readers. Our editorial team operates independently of our advertising and affiliate partnerships to ensure that our content remains unbiased and focused on providing you with the best information and recommendations based on thorough research and honest evaluations. To remain transparent, we’ve provided a list of our current affiliate partners here.

What is an Outboard Propeller?

By Judith Smith Sullivan
Updated May 23, 2024
Our promise to you
WikiMotors is dedicated to creating trustworthy, high-quality content that always prioritizes transparency, integrity, and inclusivity above all else. Our ensure that our content creation and review process includes rigorous fact-checking, evidence-based, and continual updates to ensure accuracy and reliability.

Our Promise to you

Founded in 2002, our company has been a trusted resource for readers seeking informative and engaging content. Our dedication to quality remains unwavering—and will never change. We follow a strict editorial policy, ensuring that our content is authored by highly qualified professionals and edited by subject matter experts. This guarantees that everything we publish is objective, accurate, and trustworthy.

Over the years, we've refined our approach to cover a wide range of topics, providing readers with reliable and practical advice to enhance their knowledge and skills. That's why millions of readers turn to us each year. Join us in celebrating the joy of learning, guided by standards you can trust.

Editorial Standards

At WikiMotors, we are committed to creating content that you can trust. Our editorial process is designed to ensure that every piece of content we publish is accurate, reliable, and informative.

Our team of experienced writers and editors follows a strict set of guidelines to ensure the highest quality content. We conduct thorough research, fact-check all information, and rely on credible sources to back up our claims. Our content is reviewed by subject-matter experts to ensure accuracy and clarity.

We believe in transparency and maintain editorial independence from our advertisers. Our team does not receive direct compensation from advertisers, allowing us to create unbiased content that prioritizes your interests.

An outboard propeller is the part of the lower unit of an outboard motor. It is typically fan shaped with two or more blades and powered by by gasoline. Unlike an inboard motor, the outboard motor is attached to the outside of a watercraft.

Outboard motors and propellers are quite common. They offer an advantage over inboard motors because they are easily accessible for repairs. Since the motor and propeller are self-contained, they can be upgraded or replaced with a different motor relatively easily. Inboard motors are typically more expensive and cost more time in labor to repair than outboard motors.

The type of outboard propeller varies by size, material, and design. Size is indicated by the diameter and pitch. The pitch is the calculated amount of movement the propeller creates with each revolution, and the diameter is found by measuring the blade from center hub to tip and multiplying by two. For instance, a 15 inch by 22 inch (38.1 cm by 55.88 cm) outboard propeller is 15 inches (38.1 cm) in diameter and theoretically moves the watercraft 22 inches (55.88 cm) with each turn.

Common materials for outboard propellers include stainless steel, aluminum, bronze, and composites. Watercraft propellers must withstand a great deal of strain, so they are not typically made of any type of plastic. Composite propellers are created with a mixture of nylon and glass. They are typically lighter than traditional metal propellers and are not susceptible to corrosion.

The design of the outboard propeller makes a difference in the watercraft's performance. Pitch and diameter, as well as the number of blades, affects the rotations per minute (RPM) and acceleration. Usually four-blade propellers have superior acceleration and bow lift than three-blade designs, although three-blade propellers function well for all purpose use. An increase in pitch normally translates into a lower number of RPMs, as does an increase in diameter. How well the propeller functions also depends on the size and weight of the boat.

It normally requires some trial and error to match the correct outboard propeller to the motor and watercraft. In optimization of any one aspect of propulsion, there is typically some reduction in performance in other fields. It is not usually possible to achieve optimum efficiency, speed, hauling capacity and handling with the same motor and propeller. It is recommended that several propellers be purchased for different situations. This is the best way to maximize performance on a single watercraft.

WikiMotors is dedicated to providing accurate and trustworthy information. We carefully select reputable sources and employ a rigorous fact-checking process to maintain the highest standards. To learn more about our commitment to accuracy, read our editorial process.
Discussion Comments
WikiMotors, in your inbox

Our latest articles, guides, and more, delivered daily.

WikiMotors, in your inbox

Our latest articles, guides, and more, delivered daily.