The perfect propeller can optimize the performance of your boat in several ways. There’s a lot more to propellers than the size and number of blades. From material to diameter, pitch, cup, and rotation, these are some of the basics of boat propellers you should know.

If you’re looking to buy boat props, this guide will help you to understand more about how boat propellers are made and how they work.

Basic Boat Propeller Parts

The first step to knowing how boat propellers are made and how they work is to have a solid understanding of propeller parts. They include:

  • Hub: This is the midpoint round portion that connects with the propeller shaft. It is also where the blades are attached.
  • Outer Hub and Inner Hub: Outer hub forms the attachment roots for the blade roots, and together with the inner hub they form a passage tunnel for exhaust. The inner hub is the space between the hub and the splines. It protects the drive train in case a propeller hits a hard object.
  • Blades: Fins that project from the propeller hub. The shape and the speed of the blades determine the rotation of a given propeller.
  • Blade Root and Blade Tip: The root is the point where the blade attaches to the hub. The tip is the farthest part of the blade from the propeller hub.
  • Blade Face and Blade Back: The blade face is the side that exerts high pressure to push water when the boat is moving forward. Blade back is the side with low pressure and faces towards the front of the boat.
  • Leading and Trailing Edges: The leading edge is the forward part of the blade next to to the forward part of the hub. The trailing edge is the downstream edge of the blade adjacent to the rear part of the hub.
  • Cup: A small curve on the trailing edge of the blade that allows the propeller to hold water better.
  • Diameter: The distance across the blade tips. A larger diameter increases the boat-driving control that the propeller will deliver.

How Boat Propellers Work

Boat propellers consist of corrosion-resistant materials to prevent corrosion caused by seawater. The construction process involves attaching numerous blades to the hub through forging or welding. Forged blades are stronger but cost more than the welded ones.

Before you decide to buy boat props, it’s important to learn how they work. When the boat is in water, the propeller pushes the boat ahead or pulls it backward. This depends on the pitch or rotation’s direction.

The boat engine connects to the propeller through the shaft. As the engine rotates the propeller, the radiating blades set at a pitch form a helical spiral. It then converts the power of rotation into linear thrust. The thrust acts upon water and creates pressure between the front and back surfaces. Water then flows towards the same direction, creating a strong force to aid the body to move ahead.

However, in some cases, slippage can make the propeller fail to move the expected distance. A propeller with a good design and well-performing blades will have at least 10 to 30% slippage.

When you consider buying boat props, it helps to first think about the primary use of the boat. You’ll find boat propellers made of bronze, aluminum, stainless, Nibral, and sometimes brass.

Aluminum propellers are the most affordable and are suitable for slow-moving boats but are prone to dent and scratch. So, it’s vital to consider this when choosing a boat prop.

A stainless-steel prop is tougher and can withstand harsh conditions. But, if it lacks proper blades, it can lead to shaft damage. Repairing the shaft may require more time and money as compared to replacing the propeller or repairing the blade.

Propellers made of heavy-duty brass are appropriate for high performance. Most of them have 5 or 6 blades to help speed up propulsion.

Looking to Buy Boat Props? Contact the Delta Propeller Company Today!

The Delta Propeller Company has been supplying and servicing boat propellers in North Central US for over 30 years. As proud members of the National Marine Propeller Association, we strive to provide our customers with the best boat propellers and boat propeller repair services.

Contact us today for all your boat prop needs or shop on our online store.