Nothing lasts forever right?
KiwiProps have proven to be extremely durable, and more importantly reliable. We can honestly say that if you keep a new Kiwiprop properly lubricated there are no components that regularly wear out or require replacement.
We have learned a few things over the years, however, that have led to design and material improvements often because something has ‘worn’. There are two items that led to material changes about 5 -7 years ago.
The White plastic nose cones on the aft end of the KiwiProp for some reason started developing cracks after 5-7 years in the water. To date likely less than 5% have been susceptible, but we’re no closer to understanding why. Likely some combination of fatique, impact and loads due to lack of lubrication, but no matter, the fix was to go to a slightly softer black material and we have had no issues since.
We supply the replacements n/c if your white one has a crack appear, but worth noting that even if it cracks it does not indicate imminent failure. As a matter of fact we have only had one case where the nose cone actually became partially detached and it was related to an impact situation. We often tell customers that we’re happy to send a new nose cone, but if it’s just a small crack just keep an eye on it, it may very well never get any worse or impact the performance of the prop.
The other item seems to be blade mounting pins. Again not a big issue but in the real world of marinas and boat clubs, it became apparent that when there was stray current, the pins, mostly hidden within the blade, were the most susceptible part of the prop to corrosion, resulting in the loss of a handful of $100 blades over the years.
They also seemed to show some wear when a KiwiProp was run without proper lubrication for a long period of time, again hidden for the most part.
The solution, about 5-6 years ago was to go to titanium pins and again we have provided them n/c as replacements for lost or worn pins. I still have a hard time visualizing how the SS pins were wearing, but its hard to understand all the forces acting on a propeller when powering ahead and in reverse, and also when feathering.
Many customers (and competitors) have questioned whether or not the Zytel blades wear out. The short answer is no. The real world answer is that they are a low cost sacrificial replaceable part though so in the event of collision, lobster pot wraps, dinghy painters, etc. they can be easily repaired with epoxy and filler in the case of minor dings, or replaced entirely for $110/blade.
A number of blades have been scored at the base due to a lack of lubrication or over pitching of the pitch screws but it might be unfair to call this wearing out as both conditions are self inflicted by the owner. The blades are normally OK if there is minor scoring, the eventual symptom will be to overpitch in reverse which since we are already at maximum pitch you might not even notice.
It has initiated a redesign of the reverse rollers to increase the surface contact area and spread any load that might want to ‘score’ the blade, we ship out replacement rollers n/c for anyone that is concerned about the scoring and will advise on whether the amount of scoring looks like it might warrant further repair (epoxy and filler or worst case new blade).
Well there you have it, a long winded overview based on selling and using the props for 13 years! Fair Winds.
BTW- my 13 year old KiwiProps still have their original nose cones and pins so go figure!