New fixed podded drive
Reintjes’ Fortjes drive is intended to fill the gap between the smaller commercial pod drives and leisure craft-derived units
Gearbox manufacturer Reintjes is the latest company to enter the developing market for pod drives for smaller vessels, writes Dag Pike.
The company’s new drive system, known as Fortjes, uses technology developed for use on larger ships with a drive system that uses counter-rotating propellers at each end of the pod shaft. Unlike many competitors, the Fortjes unit does not rotate around its vertical shaft to offer steering but is a fixed unit that still requires a separate rudder for directional control.
An innovative feature of the Fortjes drive is that the gearbox is incorporated into the housing at the top of the drive unit. In addition to changing the drive direction, the vertical shaft driving bevel gears in the lower housing, sending the drive to each propeller, the gearbox offers the usual ahead, neutral and astern gears. Incorporating the gears and the propulsion unit into a single unit offers scope for considerable space saving in the engine compartment.
The leg of the Fortjes drive is asymmetrical in cross section so that is can help direct the flow of the water from the forward to the aft propeller is the most efficient way. The drive unit is claimed to be suitable for most vee shaped hulls as well as those that incorporate semi-tunnels. Reintjes claims that its new drive system is around 12% more efficient that a conventional shaft and propeller propulsion system, and allows for a more simple installation in the building yard.
The Fortjes drive is suitable for vessels with speeds up to around 30 knots and so could meet the propulsion requirements of a variety of small fast craft. It is offered in five sizes that can accommodate power outputs from 300kW to 2,100kW, It is intended to fill the gap below the current ranges of pod drives that are offered for commercial vessels, entering a market where the existing pod drives have been developed from smaller units that have been mainly used in the recreational marine market.
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