I will also discuss basic propeller maintenance and inspection. The pitch and diameter are the two most common dimensions of a propeller. The diameter is self explanatory, and is fairly easy to measure. The pitch is the theoretical distance that the propeller moves forward for each revolution, usually measured in inches. The actual distance the boat moves forward for each propeller revolution is somewhat less, depending on the amount of propeller slip.
Most pleasure boats are factory equipped with aluminum propellers.
A good quality aluminum propeller will provide satisfactory performance for most family and fishing boats. Aluminum propellers are relatively inexpensive, easy to repair, and under normal conditions can last for many years. If you are happy with the performance of your prop, and it is in good condition there is no need to change it. If you are looking for better performance than can be provided by your aluminum propeller, such as ultimate top speed or better acceleration, a stainless steel propeller will probably be required. Stainless steel is much stronger than aluminum, and can consequently withstand far more abuse.