Among superyachts, the demand for pod propulsion has risen sharply in recent years. No wonder, easy manoeuvrability as well as space and efficiency gains speak in favour of diesel-powered propeller pods. However, they are being used in ever larger models and are reaching their limits. For example, Wally had to install an IPS quartet on the 27 metre long Why200 to achieve a balance between comfort and speed; the Italians chose Volvo Penta's largest possible version with 735 kilowatts per unit. The largest IPS yacht to date, the 36.50 metre long Amer 120, also relies on the same drive system, but ZF engineers have now developed the Pod 4600 for formats up to 40 metres long and a maximum engine output of 1250 kilowatts. The Friedrichshafen-based company is thus promising a reduction in the number of pods, which would make the systems of large yachts less complex and reduce overall weight and wetted surfaces. ZF claims around 15 per cent lower fuel consumption compared to conventional shaft systems. The system is designed for maximum speeds between 20 and 32 knots and is compatible with all OEM engines. Yachts with planing and semi-planing hulls of 24 to 30 metres in length are to be configured with two units and 40-metre formats with three units.
The ZF pods work in non-swirling water and act as rudders. In this way, the counter-rotating propellers are optimally supported in their power development and the horizontal thrust of the drive is also improved. Steering is electro-hydraulic at an angle of plus 30 degrees or minus 30 degrees. The automatic coordination of motors and pods allows joystick control and automatic position holding without dropping anchor.
More space in the fuselage thanks to pod configurations
As engine compartments are significantly flatter in pod configurations and are located further aft, more space can be utilised in the hull. This is a good reason why shipyards are increasingly opting for azimuthing drive units. Think of the open-air lower deck layouts of Bluegame and Sanlorenzo's SX models with their guest areas starting far aft. Azimut opted for a new utilisation of the space gained. On the Grande 26M - the 26-metre semi-glider made its debut at the Cannes Yachting Festival - the installation of the ZF pod in the stern enables a central tender garage in the direction of travel. This in turn simplifies hauling in and launching the tender. On the Grande 26M, two MAN twelve-cylinder engines supply the pods with an output of 1210 kilowatts each, enabling the smallest Grande model to accelerate to a top speed of 28 knots.
As of 2020, Volvo Penta had sold around 30,000 IPS units. With the more powerful ZF drive, significantly larger yachts are now benefiting from the system advantages of diesel-mechanical pods. Whether these will also power 40-metre formats in the next few years is probably only a matter of time.
