Improves propulsive efficiency by weakening the propeller hub vortex. This decreases propeller torque and occasionally produces increased thrust. ERMA FIRST FLEXCAP utilizes the swirl, while the fins effectively catch and absorb the force of the rotating water, eliminating the vortex and feeding the energy back into the propulsion drive train. In addition to the improved propulsive efficiency, the FLEXCAP can also be applied to reduce propeller-induced noise and vibrations. FLEXCAP is made from the same material as the propeller (NiAlBronze) and replaces the normal propeller boss cap.
Installation of the FLEXCAP is easy; it can even be installed when the vessel is afloat provided the vessel can be sufficiently trimmed. Once the FLEXCAP is installed, the only maintenance required is polishing during regular cleaning intervals. With proper underwater services, underwater installation of most of the FLEXCAP is also possible, without taking the vessel out of service.