The New Kiwi Feather
Unique new composite feathering propeller for yachts
You are now the proud
owner of an original Kiwi Feather Prop™, which has been carefully
designed and engineered to deliver many years of service on your
vessel. There are some very simple recommendations you should be
aware of to ensure your Kiwi Feather Prop™ will continue to deliver
trouble free performance in the years ahead.
Before fitting your new
Kiwi Feather Prop™ first check that the shaft is free to rotate and
can be spun easily by hand to ensure correct feathering. Wipe all
mating surfaces clean and lightly smear with marine grease including
both keyways. Ensure that the taper length will allow the nut to
pull the propeller tight on to the shaft. To ensure the key is
fitted correctly, mount the unit without the key, to ensure the
taper is tight, and then again with the key to ensure it is not
binding on the keyway which can then be ground down if required.
Larger, 1.125" and 1.250" units mount 0.250" and 0.625",
respectively, below the start of the taper. Check the fitting of the
nut prior to mounting the propeller and remove any burrs or
impediments to the smooth operation of the nut. Smear the thread
with marine grease.
A new key will be
supplied for all 1 ¼" shafts with one face ground down by 0.025"
which allows for a common boss size. Ensure the ground face is
mounted outwards. Always replace any key that is old or shows any
signs of corrosion. Keys are usually only made of brass and will
corrode rapidly. The shearing of a corroded key will result in the
automatic loss of your new propeller.
Saildrives require a
similar approach. Ensure that both internal and external splines are
scrupulously clean to avoid binding. Check that the 10 mm thick
washer which acts as a slinger is present on the shaft. Check the
Delrin nose cone is not binding on the zinc. Some units such as
Lombardini come with washers, which must be mounted. All Saildrives
require that the distance from the end of the spline to the face
taking the thrust is exactly 3.000". All Saildrive propellers then
have bosses which are ~ 3.125" long to ensure they pull up tight on
the thrust face before the M16 / M18 nut starts to bind at the end
of the thread.
Do not over tighten the
nut, which attaches
to any standard ½ inch socket driver. This is particularly important
on tapered shafts when you need to remove the propeller and when
using the Delrin nut option. Just nip it up using no more than 10
foot lbs of torque. This is equivalent to the weight of a one gallon
or five litre can of water suspended on your socket driver one foot
or 300 mm from the nut. Apply a drop of Loctite ™ to the 8mm set
screw, which is used to lock the nut onto the shaft using the
appropriate Allen key.
Again, do not over
tighten, particularly when using the Delrin nut.
NB: Saildrive nuts and
their locking screw should be checked and re-tightened at each
haulout as splines, by their nature, may fret slightly in
To ensure the propeller
feathers correctly, first throttle down to an idle, and then place
the gearbox in neutral before stopping the engine. The shaft will
then slow down as the blades align themselves with the water flow
and quickly come to a stop. The shaft will then remain stationary
without further attention.
Keep the gearbox in
neutral whenever you are sailing.
You are now ready to
enjoy the ongoing benefits from your Kiwi Feather Prop™
Please continue reading
for future maintenance and pitch adjustment
Maintenance and Pitch
Your Kiwi Feather Prop™
has been set at the recommended pitch for your installation based on
the engine model number, the reduction gear fitted, and the
particular characteristics you supplied for your vessel. You may,
however, wish to take advantage of the simple pitch adjustment
feature to accommodate the many variations between individual
vessels and operating preferences and obtain the optimal motoring
performance for your particular requirements.
[The required Allen key
is 5/32" or 4 mm]
One turn of the 8 mm
pitch screw in a clockwise direction to each blade will equate to 3
degrees of pitch [not inches of pitch] and substantially increase
the power required from the engine and drive train. This will
translate to lower engine revs. We would recommend adjustments be
made in no more than exact half turn increments to each blade, which
has the effect of varying engine revs by some 300 ~ 400
Each installation is unique and only experience can
deliver the appropriate settings and optimal cruising revs for your
vessel. A pitch setting of 20 degrees equates to a normal pitch of
~11 to 12 inches.
To maintain an equal
pitch on each blade were this to be lost, or re-acquired if a blade
was replaced, then the following procedure will provide a
When the root of the
blade is aligned with the joint line between the mushroom end
holding the reversing rollers, and the boss which carries the
blades, then the pitch is set at 20 degrees.
Simply adding or
subtracting one degree of pitch can then be executed by the above
procedure using 1/3 rd of a turn = 1 degree of pitch. For example 22
degrees of pitch would be 2/3 rd of a turn in or clockwise from the
20 degree reference.
To avoid damaging
the blade roots in reverse by exceeding the designed pitch settings
when increasing the pitch, first lock the propeller by engaging
ahead with the engine stopped. Rotate the propeller by hand into the
reverse position against the spring, and then only increase the
pitch until the blade comes up against the reversing rollers. You
will not be able to exceed 23 degrees of pitch on most
This represents the maximum pitch setting available
from your Kiwi Feather Prop™.
The Kiwi Feather Prop ™
contains lubricants sufficient until your next maintenance
Each blade must be
greased via a lubrication point, accessed by removing the small,
Phillips head, stainless screw on the blade face. In addition there
are two small grease holes. One is in the bronze casting that takes
the thrust of the pitch screws very close to the Delrin™ nose cone,
and one near the outer perimeter of the bronze sphere at the rear of
the unit. These have been chamfered to accept a standard needle
nosed grease point. You will need to remove the outer guard off the
needle. Each of these five grease points should then be filled with
high quality marine grease. We recommend Shell™ NLG12 Nautilus
Marine Grease or equivalent.
Check the reversing
rollers are free to turn.
Additional greasing of
the blades will be required if operating in very sandy environments,
and/or very shallow sandy waters, such that the propeller is
continually operating in a sandy or dirt laden environment. This
will ensure that they maintain a clean environment to minimize wear
over time. Any dirt bound in grease will be highly
To maintain the
performance of any propeller it is essential to keep both faces, and
in particular the tips clean. Barnacles and weed growth will have a
serious impact on motoring performance. We recommend painting the
whole propeller with a modern ablative antifouling, which can be
applied directly to the unit. The Zytel™ and Delrin™ require no
special undercoats. While the paint will slowly erode from the tips
of the blades over time this approach will still provide the best
overall solution to fouling of the propeller.
If not using a soft
ablative paint that will wear away quickly with any contact from a
moving blade, then care must be taken to ensure that the bottom root
surface of the blade does not start to bind on the boss from a
build-up of antifouling.
Begin by marking each
blade 1,2,3 with corresponding marks or reference positions on the
boss, which will not be removed in any subsequent cleaning
operations. This is to ensure your pitch settings are retained
Remove the small Phillips
head screws, which are used to grease the unit, halfway out of the
face of each blade. Gently tap out each retaining pin that holds the
blades with a pin punch of less than ¼" diameter. The blades can now
be removed simply by sliding off the pin on the boss. Check for wear
and corrosion on these pins which can be replaced if
Clean the pins and the
interior of each blade carefully with petroleum based cleaner, such
as turpentine, to ensure any old lubricant, which will contain dirt
and abrasives, is removed. Any areas where the blades may be binding
should now become obvious from any wear patterns. These should be
filed or sanded down. This is most likely to occur on the boss where
the root of the blades can get caught with antifouling and or
barnacles over time.
When both the mounting
pin and the blade interiors are clean and dry you are now in a
position to remount the blades on their correct pin and check for
Grease each blade bore.
Smear a tablespoon of a good marine grease, usually lithium based,
into the bore of each blade and also around the groove on the pin to
ensure the assembly is full of grease when complete. Push the blade
down fully. Surplus grease will squirt from the grease hole, which
must be open, otherwise the blade will act like a hydraulic ram and
become impossible to push back on.
Check the blade has been
remounted on its old pin. Now mount the retaining pin back into the
reverse face of the blade with a new wear face on the pin facing
outwards. Tapping gently, reinsert the pin so that it is equidistant
from each outer face of the blade.
Be careful to use a
gentle striking motion with a small hammer slightly biased towards
the leading edge of the blade which will force the leading edge of
the pin towards the trailing edge to ensure it enters the hole on
the opposite face cleanly. The pin, in effect, pivots around the
leading edge of the hole. Do not force with heavy striking. If
aligned correctly it will require no more force to go in than
required to take out. This should not be a problem, just a little
care and common sense.
Replace the small
Phillips head screws after repeating the above process on each
If high speed
autorotation occurs when sailing, check for freedom of movement of
each blade and the presence of foreign objects – typically fishing
lines or pieces of rope, flotsam etc that has been picked up by the
Each unit is biased by
modifying the last few millimeters of the trailing edge on one side
to provide a slight camber to each blade so that any tendency to
auto rotate will always be against the normal ahead direction.
Normal operation will be for the prop to slowly slow down and then
If it continues to turn
slowly, there is no problem putting it into gear to prevent this.
The blades are still feathered. The water flows around the propeller
of any yacht are very complex and turbulent. Leeway and disturbances
from the shaft and strut make specific predictions very difficult.
Eliminating rotation will minimize any potential blade movement and
thus wear over time.
The unit has been
designed and tested to engage the blades into reverse position at
shaft rpm > 300 rpm, which accommodates all popular engine and
reduction gear combinations. Engines with high reductions, i.e. >
2.5:1, must ensure they have the idle set correctly to ensure
reverse is engaged correctly. Reverse pitch is not adjustable but is
always at a maximum and thus provides an immediate engine
REMOVAL OF THE
the unit is to be removed from the shaft this must be done with a
Under no circumstances should the unit be removed with a
hammer as this will damage the face of the unit and is likely
to crack the Acetyl nose cone.
DISASSEMBLY OF THE
If disassembling the
unit, which should not be necessary, ensure when pre-loading the
internal torsion spring that the blades are held in the reverse
position to avoid damaging the spring from over-winding when reverse
is subsequently engaged. The nose cone must be sealed with white 3M
5200 Fast Cure on the joint lines and under the friction surface
which assists in preventing the nose cone turning on the shaft under
the torque from the spring. This includes the area under the thrust
groove in the boss. Clean all the matching surfaces with turpentine
before applying the 3M 5200 including the area under the thrust
groove to maximize the area of 5200. Clean up with turpentine and
allow to dry.
Whenever the boat is
hauled is an opportunity to ensure the propeller receives the
following checks to ensure it will continue to operate correctly
into the future.
Check that the attachment
nut and associated locking screws have not moved.
Ensure the blades are
free of barnacles and any marine growth. If the blades have been
antifouled as recommended this will minimize growth, but with the
expected wear near the tips these will, over time, accumulate growth
as the paint is ablated away. Any roughness on the blades will
interfere with motoring performance. Sanding with wet and dry paper
will restore the blades to their original condition. Antifoul as
Sand fair, any nicks and
dings on the leading edge from collision with flotsam.
Check that the spring
within the nose of the propeller will return the blades to the
feathered position when the blades are forced into the reverse
position while holding the shaft. Refer carefully to the above notes
Check that each of the
small reversing rollers are free to turn on the small stub
Do not attempt to
remove these machine screws as they have
been inserted with threadlock and are not intended to be removed.
They can only be taken out with heat. If tight, they can be freed up
with pliers and a thin lubricant such as a penetrating
Check that each of the
blades is free to turn on its shaft. Any stiffness here will impact
on the overall ability of the unit to feather properly in all
conditions. If it feels as if this situation will not be rectified
with subsequent lubrication, it will be necessary to remove the
blade from it’s mounting, following the instructions detailed above.
If the blade becomes free following the removal of the attachment
pin, but not the blade, then the binding will be under the root of
Careful observation of
the blade and matching surfaces will indicate where the binding is
occurring. It could be on the root of the blade from a build-up of
marine growth and/or deposits, which would need to be cleaned off.
It could be foreign material in the surface between the blade and
the pin. This would require that both surfaces be cleaned with
petroleum based cleaner such as turpentine to remove all of the
grease and any contaminants. With only 0.003" clearance between the
surfaces, it takes very little to interfere with a smooth action
about the pin.
While the blades are
pre-soaked to pre-stress and stabilize them under water, Zytel is an
aramid and may react further over time. If still binding on the
shaft after cleaning, the internal recess will need to be sanded
with a piece of sandpaper on a round mandrel such as a piece of
dowel or something similar to remove any high spots which are
causing the interference. Ensure the blade is cleaned thoroughly to
remove all traces of abrasive prior to lubrication as detailed in
the section on lubrication, above.
As a general guide each
blade should fall slowly and smoothly under it’s own weight when
placed in a horizontal position after it has been lubricated and
reassembled following the instructions above for blade
Lubricate each blade in
turn, plus the nose and aft section of the unit, as described in the
section on lubrication, above. The unit should now be ready for
We would appreciate receiving feedback from each
customer after using his or her Kiwiprop for a period. In
particular; data on maximum and cruising rpm, with corresponding
boat speeds, and the relative performance of the unit compared to
the previous propeller installation allows us to continuously refine