Kiwi prop - Composite Variable pitch

[Uncle Bob]

Originally Posted by GILow

Word of advice, stick to the NZ web site. The US one is weird. I’m not sure why it is there, except perhaps to deal with the fact that some people don’t realise there are other country codes in the DNS hierarchy.

And frankly, if you are having that much trouble working on such a simple mechanism you should hire a professional. A two year old can assemble these things.

While drunk.

Oh dear Matt, how many 2 year-olds do you know that drink to such extremes?
Asks he while enjoying a glass or two of a reasonably priced red.

[DiStefano]

Indeed, once I am done with complete disassembly - the product is simple, albeit highly customized. But the NZ website is choke full of errors, and the instructions are written in a very complicated way. In fact, the Operating Manual may be the single worst instruction manual I have ever seen. I am aware of the difference between NZ and US websites (another point of potential confusion). All in all, who has time for all such issues?

[DiStefano]

Originally Posted by GILow

Word of advice, stick to the NZ web site. The US one is weird. I’m not sure why it is there, except perhaps to deal with the fact that some people don’t realise there are other country codes in the DNS hierarchy.

And frankly, if you are having that much trouble working on such a simple mechanism you should hire a professional. A two year old can assemble these things.

While drunk.

You touched a painful spot, so let me elaborate. I respectfully disagree. The ones who should be hiring professionals are the makers of Kiwi props, not their clients. Specifically:
1) they should hire a professional to rewrite their user manual (remove contradictory advice, simplify instructions etc), fix the fuzzy photos, etc. The explanation I received (“ photos get distorted during Word to PDF conversion”) is not even funny.
2) they should hire a professional to optimize their supply chain, so that parts are available - at least in the major markets - w/o having to pay $75 per damaged seal or missing screw to ship from NZ.
3) they should hire a professional customer service advisor to ensure their dealers respond promptly and fully to each help request.
I also stand by on my view about product fragility. It may be good in certain situations (eg your case of not damaging the shaft, etc) but the prop has several parts (the spring, the Visconite sleeve and seal) which can and do break. Lines entangled in a prop is not a black swan event.

[GILow]

It took me 15 minutes to dismantle my damaged prop and swap in the new hub.

On the galley table.

I know yachties who’ve been running two of these props for a decade now without difficulty.

I really don’t understand how anyone can have so much trouble with them. They are incredibly simple and logical.

[GILow]

Originally Posted by Uncle Bob

Oh dear Matt, how many 2 year-olds do you know that drink to such extremes?

Asks he while enjoying a glass or two of a reasonably priced red.

I grew up in a strange part of town.

[DiStefano]

Originally Posted by GILow

It took me 15 minutes to dismantle my damaged prop and swap in the new hub.

On the galley table.

I know yachties who’ve been running two of these props for a decade now without difficulty.

I really don’t understand how anyone can have so much trouble with them. They are incredibly simple and logical.

Good for you. My experience has been different. To each their own. The issues I pointed out do exist.

[mikereed100]

I have been running Kiwiprops on my cat for around 45k miles now. I feel they have some advantages and disadvantages.
Pros:
-Price
-Ease of removal. They can be lubed in the water but I find it easier just to pop them off and do it in my shop.
-Light weight
-Great customer service. I once got my time zones mixed up and called John after midnight, thinking it was noon. After pointing out my mistake he nevertheless helped me with my issue.
-Easily repaired. I carry spare blades and washers.
-Adjustable pitch. This is very helpful and allows me to optimize thrust for my boat.
-Astounding thrust in reverse. Important in a cat where maneuvering in close quarters is done entirely with the engines. Also came in quite useful when a humpback surfaced between our hulls off the coast of Washington.

Cons:
-Require frequent (every 3-6 months) lubing. Still looking for a grease that will stay put.
-Blades can get dinged when striking logs, etc. On the plus side they can usually be filed smooth or repaired with JB Weld or similar.
-The fact that they are feathering rather than folding means that they pick up kelp and trash more easily.


If I had a do-over I might opt for Flex-o-folds as we spend a lot of time in latitudes where kelp is an issue and I get tired of leaning over the side with a line cutter to pick the kelp off, but that is a feathering vs folding thing, not specific to Kiwiprops. Also, if I don't keep the hubs well packed with grease I have to tease the props into reverse sometimes. All in all I have been happy with them. Over the years they have made some good tweaks to improve wear and performance.

[geoleo]

Originally Posted by Wckoek

https://www.kiwiprops.co.nz/cms/
Looks interesting and not expensive either.
Has anyone tried their propeller?
Any drawbacks to composite blades vs bronze?

I bought one for my 36ft Garden wood ketch. It became jammed internally . sent it back to NZ -- they said its fault never happened previously and refunded my money.

[Jon Hacking]

Originally Posted by Wckoek

https://www.kiwiprops.co.nz/cms/
Looks interesting and not expensive either.
Has anyone tried their propeller?
Any drawbacks to composite blades vs bronze?

We used Kiwi Props for several years on our 45' cat, seduced by the price. John (Mr.Kiwi) was very responsive to our emails when we had problems, but we had several problems:

1. The blades are relatively fragile. We had to keep a large stock of replacement blades. John said it was because we hit things with our props. I had no proof that we hadn't, but we certainly didn't feel anything, & our aluminum props certainly didn't take this sort of damage.
   
2. Reverse. The Kiwi Props go to max-pitch in reverse. John says this is in case you have to do a crash-stop. But what happened to us is that my 50HP 4JH Yanmar diesels couldn't turn the props faster than ~1400rpm in reverse. So I wasn't able to get my engine's power into the water! I'm pretty fast moving my throttle to full reverse if I need to, & THAT's the best way to get the power into the water quickly, assuming that the prop lets my engines rev up to their full-power speed.

In the end, after several discussions with John, we've decided to go with other (SS) feathering props from Oz.

FWIW, we tried Gori 2-bladed folding props all the way across the Pacific. We liked them a lot, & the engineer in me prefers folding props to feathering for several reasons, but our Gori's tended to wear, especially the pivot-pins for the blades, causing the blades to wobble alarmingly. While we didn't have any real problems with this, & couldn't feel any vibration, I worried about what this was doing to the lower bearings on my SDs.

[DiStefano]

Originally Posted by Jon Hacking

We used Kiwi Props for several years on our 45' cat, seduced by the price. John (Mr.Kiwi) was very responsive to our emails when we had problems, but we had several problems:

1. The blades are relatively fragile. We had to keep a large stock of replacement blades. John said it was because we hit things with our props. I had no proof that we hadn't, but we certainly didn't feel anything, & our aluminum props certainly didn't take this sort of damage.
   
2. Reverse. The Kiwi Props go to max-pitch in reverse. John says this is in case you have to do a crash-stop. But what happened to us is that my 50HP 4JH Yanmar diesels couldn't turn the props faster than ~1400rpm in reverse. So I wasn't able to get my engine's power into the water! I'm pretty fast moving my throttle to full reverse if I need to, & THAT's the best way to get the power into the water quickly, assuming that the prop lets my engines rev up to their full-power speed.

In the end, after several discussions with John, we've decided to go with other (SS) feathering props from Oz.

FWIW, we tried Gori 2-bladed folding props all the way across the Pacific. We liked them a lot, & the engineer in me prefers folding props to feathering for several reasons, but our Gori's tended to wear, especially the pivot-pins for the blades, causing the blades to wobble alarmingly. While we didn't have any real problems with this, & couldn't feel any vibration, I worried about what this was doing to the lower bearings on my SDs.

Jon: if your 50HP Yanmar can't turn the props faster than 1,400 RPM, what does it tell you about lesser powered engines (my Yanmars are 29HP each)? Do you feel this issue will also happen for them?

(background: after buying my yacht the way I discovered I have problems with the props in the first place was because the reverse wouldn't engage at all. All the debugging w/John's help led me to believe that the issue will be entirely solved, once the props are repaired, and well greased. But your post seems to suggest that the issue won't go away completely... do I understand what you wrote above correctly?)

[Jon Hacking]

Originally Posted by DiStefano

Jon: if your 50HP Yanmar can't turn the props faster than 1,400 RPM, what does it tell you about lesser powered engines (my Yanmars are 29HP each)? Do you feel this issue will also happen for them?

(background: after buying my yacht the way I discovered I have problems with the props in the first place was because the reverse wouldn't engage at all. All the debugging w/John's help led me to believe that the issue will be entirely solved, once the props are repaired, and well greased. But your post seems to suggest that the issue won't go away completely... do I understand what you wrote above correctly?)

Probably, yes. I've heard of a few other boats with issues in reverse with Kiwi Props. Part of that could be that we have the larger blades, at John's suggestion. It's possible, even probable, that my engines could turn faster with the smaller blades, but I'm just fed up with the things.

I HAVE had to do crash-stops sometimes, & I like the extra control of being able to use my full rev-range in reverse, & not have suddenly increased reverse thrust even at idle. These Kiwi-Props give pathetic performance in reverse. IMO, this is a safety issue, but I can't convince John of this - possibly because any other solution for reverse would require a fairly large re-engineering of the props &/or the reversing mechanism (which is probably his brain-child).

In reverse, the blades rest against some rollers. Even though those rollers roll, the blades tend to develop a groove there, which actually makes the problem worse, as the wear increases the pitch. Since I like to wake up where I went to sleep, I like to set my anchor with both engines at about 2,000rpm for 30 seconds (if I can get there, which I haven't been able to). This may account for a bit more groove on my blades. Don't other boats set their anchors?

I've thought about epoxying some fiberglass strips there, to reduce wear & to reduce the pitch in reverse, but eventually I decided this was trying to make a silk purse from a sow's ear.

Anyone want a pair of Kiwi-Props with LOTS of spares? Going cheap in Borneo...

[GILow]

Originally Posted by Jon Hacking

Anyone want a pair of Kiwi-Props with LOTS of spares? Going cheap in Borneo...

Yes, what size/type of shaft? What direction of rotation?

[DiStefano]

Hi Jon! Wow... you do raise some add'l, very good, points. Not to split hair (and to ensure my understanding is correct), but I think that with the increased wear on the blade (at the point of contact with the rotating rollers) the pitch (measured as the angle between the rotation plane - orthogonal to the prop axis, and the blade chord line) would actually decrease (not increase) over time, wouldn't it? The blade would simply "dig deeper around" the roller, thus getting flatter... FYI in my case (because of all the problems caused by the broken spring, damaged Visconite sleeve, and possibly lack of lubrication) the blades actually tended to feather, when switched into reverse. Obviously, this resulted in ZERO backward motion.
Once I receive all the spare parts, I plan to create a YouTube video about how I assemble the prop back together - this may help some folks out there, who are considering them as an option.

[Jon Hacking]

Originally Posted by GILow

Yes, what size/type of shaft? What direction of rotation?

They're for sail-drives. They all have the same splined (not tapered) shaft, & the same rotation.

Unfortunately, Ocelot's on the hard in Kudat, northern Borneo, & we're in Chile. It's going to be a few more months before we can return to her...

[mikereed100]

Originally Posted by Jon Hacking

In reverse, the blades rest against some rollers. Even though those rollers roll, the blades tend to develop a groove there, which actually makes the problem worse, as the wear increases the pitch. Since I like to wake up where I went to sleep, I like to set my anchor with both engines at about 2,000rpm for 30 seconds (if I can get there, which I haven't been able to). This may account for a bit more groove on my blades. Don't other boats set their anchors?

The original rollers were round and would quickly carve a groove in the blades as you mention. I think this is particularly true for cats as we use reverse to maneuver when docking etc. Years ago Kiwiprops switched to a triangular roller, which helped but did not prevent the grooving of the blades. More recently they have been placing a large, flat head bolt on the blades where they contact the rollers. This seems to have cured the grooving problem. Time will tell.

We too cannot bring our engines to full rpms in reverse due to the over-pitching of the props in reverse, but find that we still get plenty of thrust. We set our anchor using a 2 step process. Step one is to back down gradually, allowing the anchor to dig in. We then put the engines in neutral which allows the boat to spring forward. Step 2 is to reverse again, gaining some speed, 2-3 knots usually. When we fetch up on the rode the jerking action puts a lot more force on the anchor than simply backing down and we know we are well set.