Kiwiprop feathering propellers – Propeller
Photo: Peter Southwood, CC BY-SA 3.0, via Wikimedia Commons

Kiwiprop · Propeller

Kiwiprop feathering propellers

The Kiwiprop is a gearless feathering propeller from Kiwi Feather Props in Auckland, New Zealand: a stainless steel 316 hub carries composite blades of glass-filled Zytel, and under sail each blade swings freely on its own titanium pin into the water flow. The 3-blade K3 (since 1995) suits engines of about 15–60 hp, the 4-blade K4 (since 2011) about 50–80 hp on larger boats and catamarans, both on shafts or saildrives; K3 and K4 blades are not interchangeable. A damaged blade is replaced rather than repaired, which costs little and can even be done afloat. Kiwiprop sells factory-direct from New Zealand and through its own distributors and publishes no part numbers: spares are ordered by their price-list description plus the serial number stamped on the face of the propeller.

Manuals & documents

The links go straight to Kiwiprop. We host no manuals or drawings — the manufacturer’s copy is the current one.

Wear parts & part numbers

PartOEM numberAlso fitsNote
Propeller blade—1,2,3,4—Replacement blade, sold singly: 3 per K3, 4 per K4, each with V seal, pitch screw, threaded titanium pin and cap, Pozidriv grease screw and impact screw. Give K3 or K4 (the roots are milled for a 3″ or 4″ boss and do not swap), nominal diameter, pitch in degrees, left or right hand and “OGV” for the current ogival foil. Every blade since 2000 fits an older boss of the same type. Order by description and serial number.
Pitch screws—1,5—Pitch screws M8 × 30, SS 316, set of 3, for K3 and K4: self-locking in the blade root, 4 mm (5/32″) Allen key. Order by description and serial number.
Seal set—1,6,7—Blade-root V seals, set of 3, for every K3 and K4 since about 2008. Older units (serials about 6350–8500) have O-rings instead, sold as their own set of 3; the recesses differ, so the two do not swap. Order by description and serial number.
Blade pin—1,6,5—Titanium blade pins 1/4″, threaded with an M5 slotted cap, set of 3: standard on K3 and K4 since early 2014 and supplied with every new blade; fit with the cap end aft and blue Loctite. The pressed pins of earlier builds are still listed, but each removal loosens their fit, so Kiwiprop recommends the threaded ones. Order by description and serial number.
Reverse rollers—1,8,9,10—Reverse roller set of 3 (a K4 has 4): M8 reverse screw, Tri Roller or conical V10 roller and grease cap; also sold as roller and cap only, screw only, or caps only. Tri Rollers (standard since March 2015) fit the old 1/4″ UNC and the M8 screws alike; the screws are Loctited and peened in and come out only with heat. Order by description and serial number.
Grease nipple & plug—1,5,11,10—Grease plug screws, Pozidriv 1/2″ × #4 SS self-tapping, set of 3 (one halfway along each blade, PH0 driver, only 0.8 Nm), and the grease nipple with 1/8″ NPT thread. A needle-nose grease point for the casting holes comes with every new unit. Order by description and serial number.
Propeller hardware kit—1,12,13—Impact screws, 10g SS 316 square drive, set of 3: metal wear inserts in the blade root where the reverse roller strikes, standard since 2015/16 and set in Loctite 272. Order by description and serial number.
Propeller nut—1,7,14—K3 attachment nut, stainless, 1/2″ square drive, in three versions: saildrive (with M8 lock), shaft (all other sizes) and SAE 1 1/4″ shaft, which stands about 13 mm proud to clear the shaft end. Thread as under Specs. Order by description and serial number.
Propeller nut—1,15,13—K4 vernier nut: one M10 screw with a 5 mm spigot locks it through one of 9 holes against 8 tapped holes in the boss, giving a lock position every 5°. Nut length must match the boss. Order by description and serial number.
Nut locking screws & pins—1,16,17—K3: two M8 × 10 SS grub screws that lock the nut in the boss, and on saildrive units (from serial about 8650, 2008) the M8 × 45 fail-safe cap screw through the middle of the nut. Fit all with Loctite. Order by description and serial number.
Nut locking screws & pins—1,18,15—K4: the M10 spigot lock screw (one per boss), 7 M10 blanking set screws that only keep the threads clean and balance the hub (6 mm Allen key), and the M8 × 75 cap screw inside the saildrive nut. Order by description and serial number.
Washer kit—1,19—Nord-Lock nut locking washer pair (K3, selected builds): fitted progressively from January 2013 between nut and boss on some ISO 25 and ISO 30 units, with a shorter nut. The coarse ramp faces go towards each other. Order by description and serial number.
Nose cone—1,20,21,18,13—K3: glass-filled polypropylene, shaft or saildrive type with cap screws; saildrive cones are trimmed per drive (Volvo, Yanmar SD20–SD50, SD60, Lombardini, SP60, SD10). K4: SS 316 for all shafts or glass-filled PP for saildrives, screwed onto the boss and clamped with M8 × 40 cap screws, plus a separate SS spring-tail collar. Bed with a thin film of 3M 5200 Fast Cure or Sika and line up the punched marks again so the spring keeps its pre-tension. Order by description and serial number.
Torsion spring—1,5,21—Torsion spring, stainless, K3 or K4: it returns the blades from reverse to feathering and is wound opposite to the propeller’s hand (left-wound for a right-hand prop and vice versa). Order by description and serial number.
Plain bearing (bushing)—1,21,13—Vesconite bearing parts between boss and blade carrier. K3: internal sleeve (about 2006 on) and rear washer (about 2007 on), changed together; replace earlier white PETP parts. K4: rear washer, internal sleeve and fore (collar) washer. Order by description and serial number.
Plain bearing (bushing)—1,22,7—K3 rear washer in AB2 nickel-aluminium bronze: same size as the Vesconite washer it replaces and tougher against rope wraps and knocks; standard on current builds and can be fitted at a refurbishment. Order by description and serial number.
Propeller shaft key—1,23,7—K3 shaft keys: 1/4″ square for SAE 1″ and 1 1/8″, and 5/16″ ground down to 0.285″ for SAE 1 1/4″ (ground face outward). Replace any old or corroded key: a sheared key means a lost propeller. Order by description and serial number.
Hub castings—1,5,13—Hub castings, SS 316, sold singly: boss (saildrive spline or tapered shaft), blade carrier and, on the K3, the tripod pitch-stop casting. K3 bosses are handed; K4 bosses are not, but K4 blade carriers are. Tripods are machined to their own unit and do not always swap. Order by description and serial number.
Propeller grease—10,7,24,25—Any good lithium-based marine grease of NLGI 2; Kiwiprop names Caltex Delo ESI. Never black graphite grease. The French distributor sells a grease kit with a 150 ml push gun and a 250 ml tube; Vecta Marine (UK) supplies kits on request.
Propeller puller—26,7—Needed only on tapered shafts: a 3-leg puller for the K3, 2-leg for the K4, with the legs on the metal boss face, never on the nose cone; never hammer the prop off. Saildrive units slide off the spline by hand.
Saildrive guard collar85198416,7,27—Volvo Penta saildrives: the guard plate, a collar of about 10 mm that shields the seal and must be on the spline before the prop goes on. It belongs to the saildrive, not to the prop, and may be missing if a rope cutter was fitted before.
Saildrive guard collar196420-0925016,28,18—Yanmar SD saildrives: thrust collar (about 52 mm OD, 28.4 mm bore, 10 mm long) that stays on the drive; the Yanmar nut and lock screw are replaced by the Kiwiprop nut and M8 cap screw. One source: Kiwiprop (manual and “Yanmar SD Collar” page); not confirmed in a Yanmar catalogue.

Numbers checked against the sources below on 13 October 2026. Always confirm against your serial number and exact type before ordering.

Service intervals

TaskInterval
GreaseAt every haul-out (the factory fill lasts until the first one); more often in warm tropical or coral water and in muddy or sandy berths, which can also be done underwater between haul-outs10
PropellerMain nut and lock screws: check at every haul-out; on saildrives retighten them and renew the Loctite if anything has moved, because splines fret7,18
Season checkAt every haul-out: blade pins in place and not corroded; blades swing freely (after greasing each should drop slowly under its own weight); the spring returns the blades from reverse; reverse rollers turn freely and their screws are tight; blades sanded clean and nicks faired; no pressure washer near the blade roots18,7
AntifoulingEvery season, ablative antifouling or Prop-Speed on blades, nose cone and the first 25 mm of the casting; keep the reverse rollers and the spherical boss clear; copper-free paint on saildrives29
Shaft keyReplace when fitting the prop and whenever it is old or corroded23

From Kiwiprop’s K3 and K4 operating manuals and its maintenance pages. Kiwiprop ties these jobs to haul-outs, not to engine hours.

Specifications

ModelsK3: 3 composite blades on a 3″ boss, about 15–60 hp. K4: 4 blades on a larger 4″ boss, about 50–80 hp, for heavier boats and catamarans. Both for shaft or saildrive, left- or right-hand; the two overlap at higher power. K3 and K4 blades are not interchangeable30,31,4
Years builtK3 since 1995, K4 since October 201132
VersionsLater parts fit earlier units of the same type. Blade seals: O-rings on serials about 6350–8500, V seals since about 2008. Reverse screws 1/4″ UNC until mid-2008, then M8. Nose cones white acetal or PETP until 2008, then glass-filled polypropylene. Blades 35 % glass until mid-2009, then 50 %. Threaded titanium blade pins with caps since early 2014, Tri Rollers since March 2015, impact screws in the blade root since 2015/16, AB2 bronze rear washer on current builds22,7,9,8,12
Propeller sizesK3 nominal diameters: 14.00 (a trimmed 14.50) · 14.50 · 15.00 · 15.50 · 16.00 · 16.50 · 17.00 · 18.50 · 19.50″; the range page says 14.50–19.50″. K4: 16.50 · 17.00 · 17.50 · 18.00 · 19.50 · 20.50″ in the spec sheet, but 15.50–20.50″ on the range page. The tips measure about 1/2″ more than nominal; the same blade gives 1″ more diameter on the K4 boss. K3 blade marks near the trailing edge: one dot 16.50″, two dots 16″, three dots 15.50″, a short line 18.50″, no mark on 14.50″, 17″ or 19.50″ blades33,34,30,31,7
Max. engine powerK3: about 15–60 hp (spec sheet: under 55 hp at more than 1340 shaft rpm, above about 15 hp at less than 1400 shaft rpm). K4: about 50–80 hp depending on shaft speed; the French distributor gives about 65–100 hp for the K430,33,34,31,35
Hub sizesK3 shaft bosses: SAE 1:16 taper 1, 1 1/8 and 1 1/4″ (3/4 and 7/8″ with a shortened 1″ boss and a Tacoma sleeve kit), ISO 1:10 taper 25 and 30 mm. Nut threads 5/8 or 3/4″ UNC (1 and 1 1/8″), 7/8″ UNC (1 1/4″), M16 x 1.5 (ISO 25), M20 x 1.5 (ISO 30); keys 1/4 or 5/16″, 6 x 6 or 8 x 7 mm. 1 1/8″ and 1 1/4″ units sit 1/4″ and 5/8″ down the taper33,36
Hub sizesK4 shaft bosses: SAE 1:16 taper 1 1/4, 1 3/8 and 1 1/2″, ISO 1:10 taper 30, 35 and 40 mm, blank-bored bosses for other tapers. Nut threads 7/8, 1 and 1 1/8″ UNC (SAE), M20 x 1.5 (ISO 30; M20 x 2.0 on Beneteaus built before about 1992), M24 x 2.0 (ISO 35 and 40); keys 5/16, 5/16 and 3/8″ or 8 x 7, 10 x 8 and 12 x 8 mm34
SaildriveFits the SAE 16/32 17-tooth spline on a 28 mm shaft; nut M16 x 2, on Yanmar SD40, SD50 and SD60 M20 x 2 (the first batch of SD60 drives was cut M20 x 2.5 in error). Spline end to thrust face must measure 3.000″ (76.2 mm). Nose cones are trimmed per drive: Volvo, Yanmar SD20–SD50, Yanmar SD60, Lombardini, Beta/Nanni/Twin Disc SP60, ZF/Craftsman SD10, Sillette Sonic II. Kiwiprop advises against a K4 on an older Volvo 120S, whose cone clutch can become hard to take out of reverse, and on the small Yanmar SD20 and SD2516,20,18
Pitch adjustmentAhead 18–24°, set by an M8 pitch screw in each blade root (4 mm or 5/32″ Allen key): 1 turn = 3°, 1/3 turn = 1°, roughly 200 rpm at full throttle. Reverse is not adjustable and always goes to the maximum of about 24°. 21° on a 17″ prop is about 11–12″ of conventional pitch. Spare blades come without pitch set unless marked7,37,18
Direction of rotationLeft- or right-hand. Changing the hand takes a new boss, blades and spring on a K3 (in practice a new prop), and a new blade set, spring and blade carrier on a K4. Springs are wound opposite to the propeller’s hand38
Propeller nut torqueSquare-drive main nut (1/2″ socket), per torque table and manuals: shaft 27 Nm (20 ft-lb), saildrive 54–55 Nm (40 ft-lb) with Loctite on the threads. Fail-safe M8 cap screw inside the saildrive nut: K3 7 Nm, K4 10 Nm. Kiwiprop’s “Mounting on Saildrive” page gives about 70 Nm (50 ft-lb) for the saildrive nut instead11,7,18,16
Tightening torquesTorque table: K3 nose-cone cap screws (4 × 1/4″ UNC × 1 1/2″) 7 Nm on saildrive cones, 9 Nm on shaft cones; M8 reverse-roller screws 20 Nm (15 ft-lb); all M8 and M10 set and cap screws 7 Nm; Pozidriv grease plug screws 0.8 Nm. Other Kiwiprop documents differ: the assembly manuals and the K3 washer page give 2 and 2.5 Nm for the nose-cone screws and the assembly manuals 18 Nm (printed as 24 ft-lb) for the roller screws, the K4 manual 20 ft-lb for them, and the “Mounting on Shaft” page about 1.4 Nm for the two M8 nut lock screws11,5,13,21,18,23
LubricationGrease-filled. Marine grease NLGI 2 (Kiwiprop names Caltex Delo ESI; older manuals Shell Nautilus, lithium-based), pumped into each blade through its Pozidriv plug screw and into two small holes in the casting (front near the nose cone, rear in a lock-screw recess) with the needle-nose grease point supplied with every unit; with Tri Rollers also into the roller caps. Never black graphite grease10,7
MaterialBoss, blade carrier and pitch-stop casting SS 316 (the first units nickel-aluminium bronze). Blades DuPont Zytel HTN, black, about 50 % glass. Nose cones glass-filled polypropylene, on K4 shafts SS 316. Titanium 1/4″ blade pins; pitch screws, springs and cap screws SS 316; Vesconite sleeve, and an AB2 bronze rear washer on current builds22,18
WeightK3 under 3.4 kg; K4 about 7.5–10 kg depending on blades and bore33,34
DimensionsSpace aft, from the big end of the taper: K3 about 190 mm (14″ blades) to 210 mm, plus 16 mm on SAE 1 1/4″ shafts; K4 at least 220 mm, plus 20 mm on 40 mm and 30 mm on SAE 1 1/2″ shafts. Tip clearance to the hull at least 12 mm (1/2″), more is better36,39,40
Warranty12 months on workmanship and materials, plus a 30-day money-back trial from first launch. Wear, corrosion, impact, rope damage, seals and zincs are excluded; from serial 12000 (2012) losing the whole prop is not covered41

Good to know

  • Kiwiprop publishes no part numbers. Order spares by their description in the price list plus the serial number stamped on the face of your propeller; for blades also give K3 or K4, diameter, pitch in degrees, left or right hand and “OGV”. The order form has a field for each.1,2
  • Grease through the small Pozidriv screw in each blade and the two holes in the casting; there is no need to pull the blades off. Stop as soon as the recess is full: too much pressure from the grease gun pushes the V seals out of the blade roots.42,6
  • To swap a blade, unscrew the slotted cap, drive the titanium pin out from that side with a thin punch and slide the blade off. Check the V seal, put a little grease into the new blade with its grease screw open, tap the pin home with the cap end aft and lock the cap with blue Loctite. With the stick grade of Loctite this works underwater too.43,44
  • Change the pitch by the same amount on every blade: 1/3 turn of the pitch screw is 1° and roughly 200 rpm at full throttle. After raising the pitch, hold the shaft, turn the blades into reverse by hand and check they do not jam on the reverse rollers.37
  • To feather, throttle back to idle, go to neutral and stop the engine; once the shaft has stopped, leave it in neutral or engage forward. Do not let the shaft turn all the time, and never lock it in reverse.7,18
  • The prop has no anode of its own and needs none. Keep the saildrive maker’s zinc in place (third-party zincs may rub on the nose cone and need filing), and on a shaft fit a split collar zinc on the exposed shaft ahead of the prop.45

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Sources

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