ZF Marine’s Project Disruption technology could be a game-changer for smaller, straight-shaft inboard boats, while eventually moving to larger yachts. ZF is the first company to launch a system that mates contra-rotating props with its standard marine gear boxes in a traditional shaft-line system for inboards.

 

As contra-rotating suggests, twin props on a single shaft rotate in opposite directions. The prop pitch and loads are designed so that rotational energy in the wake is zero, while shaft vibration drops because the blades do not pass each other simultaneously.

 

Increased efficiency, improved reverse steering and less cavitation are advantages this technology could bring to boats small and large.

 

Project Disruption’s contra-rotating propellers, connected to deeper gear ratios, generate as much power as a single wheel with a larger diameter, so builders don’t have to modify hull forms. That’s particularly helpful for wakeboard boats carrying heavy ballast, but the company’s contra-rotating concept translates to large yachts too.