Nakashima Propeller develops NAP propulsion system

Nakashima Propeller in Japan has revealed details of an electric propulsion system it has developed known as the NAP or Nakashima Advanced Pop-Propeller.

The NAP comprises of a vertically positioned fixed speed electric motor that employs a non-azimuthing, low-cost, high efficiency mechanical drive, two rudders, and two shafts connected to controllable pitch propellers.

Although the vertical motor arrangement is reminiscent of modern pod design, it doesn’t contain an azimuthing unit and therefore still requires a rudder for directional control. Power is generated by a separate externally located electric motor and transmitted to the pod unit and variable pitch propellers by a conventional gear mechanism.

In comparison to the azimuthing units traditionally installed on tug boats, it is possible to employ a large diameter low-revolution propeller.

By installing the system outside the vessel?s hull, it increases potential cargo space, but its greatest advantages is derived from the fact that the initial capital investment and running costs are much lower than a fully-fledged azimuthing pod system.

The system will initially be available for power inputs of 750kW, 1150kW, 1550kW, 1950kW and 2350kW, which suggests Nakashima is aiming to capture the domestic coastal shipping market.