BLADE DAMAGE:

A fundamental design issue for the Kiwiprop unit was to utilise the known material properties of the Zytel composite blades to allow for the sacrifice of a blade(s) when the propeller comes into contact with a substantial object whilst in use.

We remain firmly of the view that it is far better to sacrifice a blade(s) costing US $ 100 each rather than damage a drive train which can cost thousands to repair or replace depending upon the level of damage. The reality is that when a propeller encounters a large solid object such as a floating log when in use something is going to break.

The photo below was taken in the Galapagos after an second encounter with a submerged log at cruise speed in transit from the Med to Australia. With spare blade sets on board they were replaced each time underwater in a few minutes and were able to continue on the voyage with no other damage and a firm convert to the concept of sacrificial blade design.

Motoring ability was substantially impaired in this situation.