Following four years of collaborative development with Mercury Marine, ZF Marine has started production on the industry’s first two-speed transmission for outboards. Production of the transmission has begun at ZF Marine’s facility in Arco, Italy.
"This project emphasizes our leading position in propulsion technology and successful collaboration with our longstanding partner Mercury Marine," Federico Decio, ZF's vice president industrial technology, pleasure craft business, said in a prepared statement. “The collaboration was defined with the objective of developing the most powerful and innovative engine in the market, and Mercury has the utmost trust in ZF Marine as a partner.”
The result of the partnership is the 7.6L V12 600hp Verado engine. The V12 outboard includes many innovative solutions, including the industry’s first automatic two-speed hydraulic transmission, according to ZF officials. The transmission is capable of handling 534-lb.-ft. of torque at a weight of just 121 lbs.
Two-speed technology for marine applications is well-known by ZF but has never been applied to outboard applications, ZF said.
Optimal selection of the reduction ratio for each gear allows the engine to achieve improved acceleration, higher efficiency, and more thrust while reducing noise. The new two-speed outboard transmission delivers maximum torque and acceleration in the first gear to help vessels get up on plane, then silently shifts to the second gear for cruising efficiency and top speed. Shifting is almost undetectable, ZF officials said.
The transmission includes a vertical wet clutch layout with precise shifting driven by proportional valves. The arrangement provides unmatched trolling capabilities at low speed and allows the transmission to shift seamlessly between the two gears. Furthermore, the proportional valves optimize vessel performance during docking and low-speed maneuvering, producing smooth and precise vessel movements, especially in combination with the joystick control system.