Buying a Boat Propeller – What Factors Are Involved?
Typically, boating enthusiasts forget to consider the importance of their boat’s propeller. The propeller is what connects the horsepower to the water. Therefore, when shopping for a propeller for your boat, make sure you make all the necessary considerations.
Finding the Right Shape and Size
Propellers are available in various shapes and sizes. When it comes to sizes, measurements are taken in terms of diameter and pitch. First and foremost, be sure that the pitch is consistent with the manufacturer’s recommended WOT (wide open throttle) range. That means you have to be able to turn the engine’s minimum rpm the engine was made for with a fully advanced throttle. As a propellers pitch increases, it builds a bigger weight or restriction for the engine to increase its rpm’s. While an engine with a horsepower of 50 can turn a 15-pitch propeller, a 750 horsepower offshore race engine may only be capable of 30 + inches of pitch.
Checking the Diameter
Diameter can also be a factor in terms of rpm capabilities and some other boat and hull personalities.
Another factor can impact impact rpm capabilities and certain other boat and hull personalities, is diameter. A good number of the diameter choices are predetermined by the manufacturer for the user. In majority of low-performance applications, this works rather well. However, overall performance can be dramatically improved by fine tuning diameter. More diameter typically means lower rpm, and vice-versa. Changes in diameter will adjust the running attitude of the hulls as well. Not that diameter adjustments are always necessary though, considering buyers can match stock diameters to propeller types.
Theoretically speaking, less blades mean higher speeds. This is based on the fact that more blades cause more metal in the water, thus more drag. But with a boat that is running inefficiently, a higher number of blades could mean that the boat has more”hook up” ability and may perform better thoughout the torque band. The boat’s specific application will partly dictate the number of blades needed for optimal results.
Choosing the right boat propeller can indeed be intimidating. Seeking the help of a trained professional is the best way to optimize your boat set-up. Most will be glad to help by sharing their knowledge on the subject. It’s probably not even necessary to meet them in person. You can join online forums and get the help you need there.
Finally, the most crucial starting point is to be aware of your engine or engines capabilities. When you’ve got this out of the way, you can be sure that the engine package is protected from propping-related improve rpm. From here, you can decide if you would like to upgrade its performance.