To help you figure out what your vessel needs to operate at its very best, your design should account for different factors affecting propeller efficiency. Allow us to teach what some of these factors are and how you can account for them.
The diameter of your propeller is closely related to the speed of the prop shaft. The lower the speed of your prop shaft, the more efficient your propeller becomes. However, this lower speed also leads to greater torque in the prop shaft that will require a larger shaft and gearbox in order to function. For this reason, you want to find a suitable balance between the diameter of your propeller and how much torque your ship can handle.
The number of blades on your propeller affects how well your vessel will handle in the water. The more blades your propeller has, the better “grip” it has on the water, therefore minimizing draft by lifting the hull out of the water more. However, the tradeoff for more blades is a decrease in speed, as additional blades mean additional drag holding you back.
One of the most important factors affecting propeller efficiency is the revolutions per minute (RPM). RPM represents the number of full rotations a propeller makes within a minute. The rotational speed must differ from the resonant frequencies of the prop shaft, hull, and other propulsion components. High RPM is only beneficial for high-speed vessels. So, once again, ensure you find a balance to find the optimal RPM for your craft.
Relating back to your propeller’s diameter, the ratio between your boat’s pitch and the propeller’s diameter plays a large role in the propulsive efficiency and corresponds to a particular RPM. Finding a balanced ratio between the pitch and propeller diameter is key to most efficiently improving the flow of water around the propeller. However, this ratio can be supplemented with the addition of components such as stern tunnels, wake equalizing ducts, or a rudder bulb system.
• Available in 3 or 4 or 5-blades,even 6 blades
• Available in Mn-Bronze, Ni-Al-Bronze and CF-3,CF-3M Stainless Steel
• Available Diameter 11” to 196”
• Custom configurations available