Reintjes developments

Designed specifically for fast vessels this new drive is claimed to be effective on hulls operating at up to 35 knots. The higher efficiency comes from the use of contra-rotating propellers and by the fact that the propulsion thrust is fully horizontal and thus all of the power transmitted operates to generate forward thrust.

The Fortjes Drive is offered in five sizes that range from power inputs from 300 to 3000 kW with larger sizes being available on request. This makes the units suitable for a wide range of workboats although at this stage the units do not have classification society approvals which may be a requirement for many applications.

With Reintjes gearbox experience, the ahead, neutral and astern gearbox is incorporated as an integral part of the upper section of the unit. A power take-off can be incorporated into this gearbox and unlike many other drive systems these units are offered with complete freedom about the engine that they are connected to. Reintjes claims that the system offers a much more compact installation that conventional shaft and propeller drive systems and the high efficiency that can be translated into higher speeds or reduced fuel consumption.

The Fortjes Drive has been design to be fitted to a variety of hull shapes. For a vee hull to can be mounted directly into the hull where it may protrude at an angle to the horizontal or it can be mounted vertically in a semi-tunnel. The drive does require the vessel to be fitted with a conventional rudder for directional control.

Reintjes has also developed an electric hybrid system that can operate from its range of gearboxes. This system can offer both silent electric propulsion or electricity generation from the main engine power. The system is primarily designed for fitting to ships that spend some time operating at low speeds where the electric propulsion can offer an effective solution but it can also be a viable solution for general shipping where the main function would be to act as a shaft generator.

Reintjes offers these motor/generator units in a variety of sizes to suit vessels with main engines from 400 to 1200 kW. The motor/generators are offered in sizes from 60 to 100 kW which is adequate power for low speed propulsion where the electric power drives the main propeller shaft.

The motor/generators connect to the main gearbox by what is effectively a power take-off link in the gearbox. The motor/generators connect via a flange so that the whole unit is integral with the gearbox but supporting mountings can be fitted where required. The electric units are water-cooled using connections from the gearbox oil cooler.

The full range of control functions of the gearbox is available for the electric motor when it is being used for propulsion so that the same control levers can be used. The motor unit is vertically offset from the main shaft. Part of the supply from Reintjes is a frequency converter so that the motor speed is controlled by varying the frequency of the AC current.

When in motor mode, the unit can be powered from the ship’s generators or from a battery pack and the motor can be used separately from the main engine or in conjunction with it as a booster. In generator mode the unit can supply power to the main switchboard or to charge onboard batteries.

This hybrid system has already been fitted to a variety of vessels including fishing vessels, offshore support craft, coastal ships and super yachts. Reintjes has designed the unit to be a flexible as possible and it can be fitted to a new installation or as a refit.

By Dag Pike