The KiwiProp is often 1/2 the mass of the competition. It’s easy to see why with all of the elabourate bronze or Stainless pieces that make up most feathering propellers. Our simple Stainless Steel Hub with composite Zytel blades comes in at less than 3.4kg.
Intuitively it must be easier for your engine to get 3.4 kg spinning than say double that for most of our competitors, but that advantage is shortlived. When you start talking balance and vibration throughout a drive train, many boat owners have dealt with vibration issues at certain rpms, no real explanation other than you’ve got a slender mostly unsupported shaft trying to spin a large diameter propeller.
The potential for vibration is directly proportional to the amount of mass you are spinning AND it’s distance from the centerline of the shaft. Whether or not there are any wear issues over time or impact related variations, the potential is there simply because the mass is there (or maybe not there in the case of a broken blade). A quick look at the KiwiProp and you will notice that likely 90% or more of the mass is concentrated in the Stainless Steel hub close to the shaft. This hub is so strong that we have never seen one damaged or bent, even in cases where the blades have been totally destroyed (that’s a story for a boat show if you ever cross paths with us!). In sharp contrast every bronze and full stainless steel propeller on the market relies on a significant amount of mass in the blades in order to initiate their feathering or reverse engagement.
Visualize the momentum of a heavy tip weighted bronze blade slamming into position repeatedly versus our lightweight Zytel blade simply flipping over onto its pitch stop thousands of times throughout the life of your propeller and its easy to accept that there is likely a benefit to spinning 3.4kg around rather than 7-9kg of elabourate finely machined bronze. There will never be any data to demonstrate how this might make your drive train happier in the long run, but anecdotally we can tell you that we almost never have any vibration issues, and the other guys almost always do- eventually.
I can’t count how many times a customer has hauled their boat and found a piece of a blade missing, remembered hitting something earlier in the season but thought everything was fine because there was no vibration or performance change. Everything was fine, small chip, fix it with epoxy and filler, big structural chunk missing you might want to order a new blade for $110 that you can replace yourself in under 5 minutes.