alant
Active member
Anyone had any issues/problems with these?
Kiwi prop?
- Thread starter alant
- Start date
theoldsalt
Active member
Reason for asking? Do you have problems or are you thinking of buying - maybe.
alant
Active member
SIL is buying a boat, with a Kiwi fitted & the surveyor thought it handled oddly astern (as did the vendor when questioned), but nothing obvious found on liftout.
wizard
Well-known member
They are very powerful in astern even on low revs, brilliant for slowing you down quickly. Had one for5 years very happy.
Tranona
Well-known member
With a lowish hp engine they can be slow to swing into reverse. It may well need greasing. Worth talking to the importer Vecta Marine.
Norman_E
Well-known member
The Kiwiprop has its pitch adjustable as regards forward propulsion but is fixed at maximum pitch astern. Excessive pitch in astern may cause too much prop walk. I did once see that the astern pitch could be reduced by fitting different reversing rollers, but cannot now find the link. I believe that the non standard rollers were not an official Kiwiprop part.
FullCircle
Well-known member
Reverse will be a problem if the unit has not been fully greased in the body (particularly) as well as the blades. Will result in the thing walking sideways, and not achieving much more than about 1500rom in reverse even at full throttle.
You need toy work the mechanism back and forth on the hard whilst pumping in the Mobil grease until it oozes out of every joint, which stops the barnacles taking residence.
Had mine for 8 seasons now, and wouldn't swap it.
You need toy work the mechanism back and forth on the hard whilst pumping in the Mobil grease until it oozes out of every joint, which stops the barnacles taking residence.
Had mine for 8 seasons now, and wouldn't swap it.
rotrax
Well-known member
Only had ours for five, but echo your sentiments.
nimbusgb
Active member
Ditto and agree very powerful in reverse.
Plevier
Active member
I was looking at making oversize rollers but never got a round tuit. The designer says you can't, they will obstruct the blades from flipping, but I thought there was enough clearance for a modest increase in diameter.
My problem was a VP 2020D engine with the latest fitment of a ZF gearbox (VP badged). Unlike the gearbox on earlier variants of the 2020, this has a small reduction ratio astern, lower than forward, i.e. a relatively high shaft rpm. The 24 degree preset reverse pitch is just too much for it, it would only do about 1200rpm (with smoke) at WOT and obviously not give any sustained thrust after the initial bite of the blades. This is a definite problem with this engine/gearbox combination. It was an engine in prime condition, only 400hrs from new, not worn out.
The Kiwiprop solution that they keep in their back pockets is to put a self tapping screw with a 2-3mm thick domed head into each blade where it will bear on the standard roller when in reverse to reduce the pitch. It works but does beat up the roller a bit. With this done, reducing my reverse pitch to very close to the 19 degree forward pitch I used, astern performance became acceptable.
It is also vital to keep it well greased and make sure the blades flip freely, and make sure the reversing roller stops turn easily.
So it can be a bit finnicky but overall yes a decent product.
BelleSerene
Active member
They're not as robust as metal feathering props. I put one on Belle Serene and echo the comments above: powerful astern; great for stopping; manageable prop walk. But one of its three blades fell off to the bottom of the sea - presumably on impact with a floating plank or something - and the two halves of the spherical bulb developed significant play. I eventually replaced mine with a Featherstream.
tri39
New member
I'm very pleased with mine, but you do need 20HP plus to operate them with a slightly higher tick over to prevent stalling.
My 2GM20 was only just up to it and struggled in reverse. But the 3YM20 is 17% more powerful and copes well with the greased prop.
As other have said you won't get the best out of the very powerful and useful reverse unless the hub and blades are well lubricated,
which is easy if stored ashore, but not if permanently afloat!!
I think they must have among the lowest drag when trailing those fins, which compensate for the diff angle between water flow under the hull and the shaft angle.
They def seem to improve light airs sailing speed.
My 2GM20 was only just up to it and struggled in reverse. But the 3YM20 is 17% more powerful and copes well with the greased prop.
As other have said you won't get the best out of the very powerful and useful reverse unless the hub and blades are well lubricated,
which is easy if stored ashore, but not if permanently afloat!!
I think they must have among the lowest drag when trailing those fins, which compensate for the diff angle between water flow under the hull and the shaft angle.
They def seem to improve light airs sailing speed.
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FullCircle
Well-known member
I thumped something hard in the North Sea. It took a chunk out of one of the blades, but it kept working just a vibration up through the shaft. I replaced the blade.
I also had 60ft of fishing net wrapped up which got chopped up by the Ambassador Stripper, but the blades must have been under stress too.
Each year, I even up the 3 blades so they all have the damage faired out, and match each other. That keeps the vibration down.
I have never lost a blade in over 1000 hours of motoring. In fact, every time I check the retaining pins, they have never moved, and seem to have the same insertion/retention as when I fitted the prop in 2006.
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ianj99
Active member
I do get much prop walk so crash stops are 'interesting'. Otherwise minimal revs or short bursts of power then coasting are the antidote.
Not had any problems but do exercise it regularly out of season. After a month gap, when I tried it astern, the engine wouldn't rev at all, so gave it some revs ahead and tried again. All okay this time.
Not had any problems but do exercise it regularly out of season. After a month gap, when I tried it astern, the engine wouldn't rev at all, so gave it some revs ahead and tried again. All okay this time.
knuterikt
Active member
If it was a "floating plank or something" that hit your propeller do you think a fixed prop or a Featherstream would have survived without transferring the forces somewhere else?
savageseadog
Well-known member
My solution to the reverse issue was to going be to screw a stainless plate/shim to the blade face where the reverse rollers bore on them. The pitch would have been reduced and there would have been less wear on the blades. In the end I changed to a conventional folder before I got the chance to do it as I was fairly sure the Kiwi had more drag.
ianj99
Active member
One feature I like about the Kiwi is the ability to adjust the ahead pitch by simply turning a 4mm socket screw near the root of each blade - i.e. no dismantling needed. You can fine tune it to get the results you want. In my case a quiet cruising rpm of about 2000 and max rpm of 2500-2600 (Perkins 4108).
BelleSerene
Active member
Survived without the blade shearing and falling into the deep? Yes.
Without transferring the forces elsewhere? Obviously not, but the shaft and engine would take the shock.
ianj99
Active member
I'd be more concerned about the gearbox or drive plate. Kiwi blades can be fitted in situ if you can hold your breath and even 2 blades should get you home if you aren't carrying a spare.
I sometimes think that the low price works against them - some owners are too snooty to spend so little and on something with plastic blades!
tri39
New member
I'm carrying a spare blade. I think that's the way to guarantee you won't need it!
I also find despite the handbooks advice to leave gearbox in neutral, I have to engage gear when sailing to prevent prop spin,
altho the blades are trailing correctly and you'd think impart no rotational force?! IIRC I think I use reverse to stop rotation when sailing,
but then can find that I'm unable to shift lever into neutral without starting engine, so some pressure on gearbox cogs.
Still very pleased with performance and price!
I also find despite the handbooks advice to leave gearbox in neutral, I have to engage gear when sailing to prevent prop spin,
altho the blades are trailing correctly and you'd think impart no rotational force?! IIRC I think I use reverse to stop rotation when sailing,
but then can find that I'm unable to shift lever into neutral without starting engine, so some pressure on gearbox cogs.
Still very pleased with performance and price!
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