For someone who is new to the world of boat props, the terminology used in describing various types and parts of boat propellers can be quite confusing. Given below is a brief description about various terms that you might come across in trying to find yourself a suitable boat propeller.
The parts of a boat prop: The normal boat propeller is made of either three or four blades which surround the hub. The hub, in turn, connects the blades of the propeller to the engines drive shaft. The blades are angled in the way that enables them to screw through water, thereby moving the boat ahead. The leading edge refers to the end of the blade that cuts through water, and the opposite side is referred to as the trailing edge.
Spline: This refers to the teeth of the drive shaft which is not really a propeller part. The design of a hub allows it to fit a shaft in accordance to number of splines.
The features of a boat prop: Boat props are classified by their diameter and pitch, and this is often displayed as 2 numbers (in inches), such as 15.5 X 12. One can usually find this stamped on the props hub. The 1st number refers to the props diameter (which would be double the distance from the blades end to the hubs center). The 2nd number refers to the props pitch. The pitch refers to the distance that the propeller can theoretically travel through with every revolution. A prop with a 12 inch pitch could travel around 1 foot with a single revolution. Pitch is often looked upon as a theoretical figure because a prop pitch can experience slips in varied real world scenarios. A slip refers to the difference in ratio between the actual distance that is traveled and the props given pitch. This slip can be varied under similar conditions, an example being that an efficiently planned boat could experience only a 10 percent slip, where as a heavy work boat could experience as much as 80 percent slip.
Rotation of a propeller can be right or left hand, and most boat propellers come with right hand rotation. Left handed rotation is generally found aboard boats that require heavy steering wherein the motors torque is countered using double engines.
A cupped blade is used to describe blades that have undergone special treatment wherein the trailing edges are curved. This is known to elevate performance levels in specific scenarios.
The rake is used to refer to the angle created by the blade and the hub. A negative rake would indicate that the props blades point forward and this is normally done for adding strength.
In buying a new propeller, it is essential that you make a list of your engines specifications such as its make, brand, model, horse power, etc; and also the specifications of your existing prop including the material it is made of, its diameter, its pitch, the number of blades it has, etc. With these details taken care, you can well be on your way to get yourself a new boat prop.
The parts of a boat prop: The normal boat propeller is made of either three or four blades which surround the hub. The hub, in turn, connects the blades of the propeller to the engines drive shaft. The blades are angled in the way that enables them to screw through water, thereby moving the boat ahead. The leading edge refers to the end of the blade that cuts through water, and the opposite side is referred to as the trailing edge.
Spline: This refers to the teeth of the drive shaft which is not really a propeller part. The design of a hub allows it to fit a shaft in accordance to number of splines.
The features of a boat prop: Boat props are classified by their diameter and pitch, and this is often displayed as 2 numbers (in inches), such as 15.5 X 12. One can usually find this stamped on the props hub. The 1st number refers to the props diameter (which would be double the distance from the blades end to the hubs center). The 2nd number refers to the props pitch. The pitch refers to the distance that the propeller can theoretically travel through with every revolution. A prop with a 12 inch pitch could travel around 1 foot with a single revolution. Pitch is often looked upon as a theoretical figure because a prop pitch can experience slips in varied real world scenarios. A slip refers to the difference in ratio between the actual distance that is traveled and the props given pitch. This slip can be varied under similar conditions, an example being that an efficiently planned boat could experience only a 10 percent slip, where as a heavy work boat could experience as much as 80 percent slip.
Rotation of a propeller can be right or left hand, and most boat propellers come with right hand rotation. Left handed rotation is generally found aboard boats that require heavy steering wherein the motors torque is countered using double engines.
A cupped blade is used to describe blades that have undergone special treatment wherein the trailing edges are curved. This is known to elevate performance levels in specific scenarios.
The rake is used to refer to the angle created by the blade and the hub. A negative rake would indicate that the props blades point forward and this is normally done for adding strength.
In buying a new propeller, it is essential that you make a list of your engines specifications such as its make, brand, model, horse power, etc; and also the specifications of your existing prop including the material it is made of, its diameter, its pitch, the number of blades it has, etc. With these details taken care, you can well be on your way to get yourself a new boat prop.
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