Rotation Change

We are often asked is it possible to change the rotation of a Kiwiprop unit so they rotate in the opposite direction in Ahead.

With two internal dogs and three reverse rollers - the position of the reverse rollers is not symmetric on the boss so that on the K3 unit, a Left Hand Boss can not be used for a Right Handed unit or vica versa.

You would need a new boss, new blades and a new spring - apart from the blade carrier and tripod casting effectively a new propeller. In these cases we advise it is better to sell one unit and buy another.

For the K4 unit  with two dogs and four reverse rollers - the boss is common but you would need a new blade set, new spring and in this design a new blade carrier. Again selling the prop and buying a new one probably makes more sense.

For the larger engines associated with the K4 units - they often have gearboxes that can run in either direction eg  PRM,  Twin Disc and in these cases - simply swapping the control cables to the opposite sector is all that is required to run the unit in the opposite direction.

Another approach to be considered is to run the gearbox in reverse.

All Volvo gearboxes are bi-directional -  but not all have the same ratios in Ahead and Astern.

The popular PRM gearboxes are also bi-directional and can be run in either direction. Being activated by an engine-driven hydraulic pump means they cannot be locked in gear to prevent shaft rotation when the engine is stopped.