Maybe this info will help you out on getting the right prop for your boat.
Prop Pitch & RPM's
For safety, and efficient performance, it is critical that your engine operates within the RPM range recommended by the manufacturer.
A change in the prop pitch will increase or decrease the engine RPM's and can be used to bring them into the recommended range. A 2" pitch increase (for example, from 21" to 23") will result in approximately a 300-400 RPM decrease and vice versa.
The correct prop allows the engine's RPM to run within the top end of the manufacturers recommendation.
3 vs. 4 Blade Props
3-blade props are great on most boats as they offer good all around performance, better efficiency, and can achieve higher speeds. Switching from 4 to 3-blades generally requires a 1" pitch increase.
4-blade props work well with bass, pontoon & high performance boats as they provide better acceleration, keep a boat on plane with fewer RPM's, and produce less vibration at high speeds. Switching from 3 to 4-blades generally requires a 1" pitch decrease.
Aluminum vs Stainless Steel
Aluminum props are a great choice for small and medium sized boats. They are inexpensive and under normal conditions can last for many years. When running your boat in an area where striking the bottom is likely, aluminum blades can flex, helping prevent damage to your engine.
Stainless steel props are ideal for large or heavy boats and boats running in saltwater. Although more expensive than aluminum, stainless steel props are more durable and will last longer. When running your boat at speeds over 50 mph, stainless props will perform better than aluminum.
Diameter is the width of the circle that the prop would make when rotating.
Prop diameter does not affect the fit of the prop on a boat.
The diameter of your prop can vary by up to 1/2" with no discernable change in performance.
Caution: Before increasing the diameter of your prop, make sure there will be enough clearance between the blades and cavitation plate or anode on your engine.
2-Piece propellers consist of the outer prop housing and a removable center hub.
The removable hub easily slips into the outer piece, allowing you to have multiple props for different applications at a lower price. When the prop blades become worn or damaged they can be replaced while keeping the same hub piece.
2-piece propellers perform the same as the 1-piece/fixed hub versions.
Prices listed include both the housing and appropriate hub.
Both parts are added to your cart making it easy to find your complete propeller.
you can look for props and buy them at this link: http://boatpropellers.iboats.com/