Source:http://www.plasticomp.com/propelled-to-success/

Piranha propeller is a high strength replacement parts and made from a kind of long glass fiber thermoplastic composite materials. The long glass fiber thermoplastic developed by the PlastiComp company.

Piranha’s unique composite propeller design consists of a center hub with three or four slots for inserting interchangeable blades of varying size and pitch.

Easily changing a damaged or broken blade instead of the entire prop lowers ownership cost; interchangeability also allows tuning of propulsion thrust to meet a boats intended use, for either speed or transporting loads.

When a metal propeller blade strikes a submersed obstacle, it can permanently bend or break, with severe impact forces often causing additional costly damage to the motors lower unit.

With a Piranha composite propeller, the blades flex and absorb the energy from minor impacts. At higher impacts, the blades, which have lower shear strength than metal, sacrifice themselves by breaking and releasing energy before transferring damaging forces to the motors lower unit.

Lower unit repairs can cost up to several thousand dollars, making a $25 composite replacement blade a considerable cost saver, according to Stahl.

Stahl’s first propeller designs used a 60% long glass fiber reinforced nylon 6 composite and testing on higher horsepower motors was successful.