Cat to launch new engine/drive combo
Caterpillar Marine has developed a new pod drive unit that has been designed to match with its latest C8.7 diesel engine.
Caterpillar is new to the engine/drive market but is now offering some of its engines with the Zeus Pod Drive. This drive unit was developed by ZF and features 360° rotation and fine control for manoeuvring is tight spaces.
The Cat Three60 Pod 650 is installed in a hull recess to provide vertical mounting on a deep vee hull. The below the water unit can rotate through 360°, allowing the thrust to be directed in any desired direction offering steering control. It is fitted with contra-rotating propellers that are located behind the drive leg, offering some protection from debris in the water.
The control for the drive offers two options, lever control and a joystick. The lever control offers a conventional control system whilst the joystick combines the throttle, the gearbox and the pod angle via a computer to give delicate boat control in any desired direction and speed. The unit can also be combined with a GPS to allow a sky hook function that maintains the boat’s position against wind and tide.
The engine incorporated into this package is the C8.5 diesel that was developed jointly with Fiat Powertrain Technologies (FPT). This engine, which has undergone prototype testing by patrol boat builder FB Design, incorporates a supercharger in addition to the normal turbocharger. The supercharger cuts in as soon as the throttles are opened and gives full torque at low speeds. In a conventional diesel there is torque lag before the engine reaches the speed where the turbocharger becomes operational but, with the powerful torque at low speed of the new system, the engine is well suited for use with surface drives where high torque is needed at low speeds.
The supercharger is coupled to the engine via an electromagnetic clutch. This allows it to be disconnected once the turbocharger is fully operational, thus reducing its load on the engine. On trials with a surface drive patrol boat the new engine cut the time to plane by about one third.
The new diesel engine, which produces 650 hp at 2,300 rpm, has been specifically designed for high performance boats. When coupled to the new pod drive it will be equally suitable for a wide range of work and patrol boats that require easy and delicate manoeuvring as well as good performance. The new diesel is available now but the new pod drive will not be on the market until early 2015.
By Dag Pike
