Manual
  LiteratureHome Page  
 

The New Kiwi Feather Prop ...
Unique new composite feathering propeller for yachts

INSTALLATION MANUAL   pdf download

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 use.

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 recommendations.

 

Maintenance and Pitch Adjustment Recommendations

PITCH SETTINGS:

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 rpm.

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 solution:

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.

IMPORTANT:

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 units.

This represents the maximum pitch setting available from your Kiwi Feather Prop™.

LUBRICATION:

The Kiwi Feather Prop ™ contains lubricants sufficient until your next maintenance haulout.

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 abrasive.

ANTIFOULING:

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.

REMOVAL OF BLADES:

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 correctly.

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 required.

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 smooth rotation.

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 blade.

AUTO ROTATION:

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 propeller.

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 stop.

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.

IDLE SPEED:

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 load.

REMOVAL OF THE UNIT:

If the unit is to be removed from the shaft this must be done with a puller.

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 UNIT:

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.

ANNUAL MAINTENANCE:

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 suggested above.

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 on disassembly.

Check that each of the small reversing rollers are free to turn on the small stub shafts.

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 spray.

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 the blade.

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 removal.

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 another season.

CUSTOMER FEEDBACK:

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 sizing recommendations.

 

Literature | Home Page




Starfield Technologies, Inc.