FREQUENTLY ASKED QUESTIONS

Q. What's the difference between Aluminum and Stainless Steel Propellers?
A. Most pleasure boats are factory equipped with aluminum propellers. Aluminum proleppers are relatively inexpensive, easy to repair, and under normal conditions can last for many years.

Stainelss steel is more expensive, but much stronger and durable than aluminum. If you are looking for better performanc than can be provided by an aluminum propeller, such as ultimate top speed or better acceleration, a stainless steel propeller my be required.

Q. Can propellers be re-pitched? If so, how far?
A. The pitch on most propellers can be changed. On aluminum propellers a maximum change of one inch of pitch up or down is recommended. Stainless steel can be changed up to two inches of pitch, up or down. One inch of pitch equals approximately 125 rpm. Lower pitch to gain rpm, increase pitch to lose rpm. Modifications will void the propeller warranty. The work of individual prop shops cannot be controlled, especially when adding cup.

Q. Why is my stainless steel propeller changing color?
A. A stainless steel propeller that is turning white has been exposed to a high lime and or calcium (oxidation) condition. Readily available commercial products will remove this and keep deposits of calcium and lime away. A coating of chrome polish will help deter this formation.

Q. Why is my stainless steel propeller rusting?
A. Stainless Steel is just as its name implies -- it "stains" less than normal carbon steel. Only the highest quality stainless steel available is used. Rust can occur under numerous circumstances, including polluted water and galvanic corrosion. This can be caused by the boat, environmental galvanic activity, (i.e. a marina's electrical system), and oxygen depletion which can be caused by shutting off air to the propeller (shrink wrap or wrapping drive/prop in plastic). Since this is a post purchase cosmetic defect and has no bearing on performance, there is no warranty for rust. The rust can be removed with rubbing compounds. A Scotch brite pad is OK but do not use steel wool. The propeller can be polished and sealed with a chrome polish.

Q. How should I maintain and service my propeller?
A. Essential to good propeller maintenance is periodic inspection to detect even small dings, which can lead to blade failure if not dressed or repaired. A damaged propeller, even one that only appears slightly damaged by running through silt and sand, can significantly reduce performance efficiency and fuel economy, and can more severely damage itself through cavitation erosion emanating from the blades' irregular leading edges. In one test with a damaged propeller, top speed fell more than 13%. Acceleration was off over 37%. Optimum cruise miles slowed 21%. Worse yet, damage usually is not done to each blade uniformly and, therefore, the damage can set up imbalance vibrations that can cause fatigue damage to other parts of the engine or drive. If you boat in shallow or rocky waters, you will want to check your propeller more frequently for possible damage.

Q. Will a stainless steel propeller make my boat faster?
A. Generally, yes, a steel propeller will be faster. If the designs are the same, the steel propeller can be made with thinner blades that run faster and with greater strength. Also, most stainless steel propellers take advantage of performance enhancing designs to gain even more advantages over aluminum.