Repairing or replacing lower units is expensive. Piranha Propellers are so effective in reducing or even eliminating damage, some insurance companies will even offer discounts on premiums. A boat propeller is a critical component to the performance of a boat. Damaged propellers will not only degrade performance, but can cause excessive wear on the lower unit. Spare Piranha Propellers blades are easily stored, and replacement of a damaged blade only takes a few minutes. With the replacement Piranha Propellers blades on hand, it is simple to restore a damaged propeller to factory new specifications.