Windpilot · Wind-vane self-steering

Windpilot Pacific

The Windpilot Pacific is a servo-pendulum wind-vane gear from Peter Foerthmann’s Windpilot in Hamburg: a plywood vane turns a pendulum blade in the water through a bronze bevel-gear linkage, and the swinging pendulum pulls two lines that steer the boat’s own tiller or wheel. The current die-cast aluminium version dates from 1998 and suits boats up to about 60 ft; its siblings are the smaller Pacific Light for tiller boats, the Pacific Plus, where the same pendulum drives a separate auxiliary rudder, and the SOS Rudder, an emergency rudder that mounts on the Pacific bracket. MF0 to MF5 are mounting brackets (Windpilot’s flange system), not separate models, and the older Atlantik and Caribic auxiliary-rudder gears are history, with no parts data from Windpilot. The part numbers here apply from 1998: units built 1985–98 carry a different two-digit numbering and are not covered, and Windpilot sells gears and spares direct from Hamburg, not through dealers.

Manuals & documents

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

Wear parts & part numbers

PartOEM numberAlso fitsNote
Airvane1001,2,3,4,5—Windvane of 6 mm marine plywood (AW100), 900 × 190 mm; the same number for Pacific, Pacific Light and Pacific Plus. A replacement or home-made vane must match the original’s weight: no heavier than the lead counterweight 120 and at most 50 g lighter (paint counts).
Water paddle (servo blade)440 · 445 · 4501,2,6,3,7—Pendulum rudder blade. Windpilot’s current parts lists give a three-part AlMg5 blade: head 440, section 445 (20 × 120 × 800 mm) and end cap 450. Older blades are wooden: Windpilot’s standards page describes an epoxied Western Hemlock blade and the Pacific Light manual lists 440 as plywood, so check which one you have before ordering. Never antifoul it; varnish only.
Blade pin435 · 4381,2,6,4,5—Blade pivot bolt 435 (M10 × 55 stainless, with washers 436 and nut 437) and Delrin blade pin 438 (6 × 45 mm). Bolt 435 is the overload protection: only snug it, so that friction holds the blade and it can swing up when it hits something. Same numbers on Pacific Light and Pacific Plus.
Plain bearing (bushing)3281,2,6,4,5—Main bearing bush of the bevel-gear linkage, Delrin, 30 × 64 × 42 mm. The bearing Windpilot singles out: clean salt and oil out of it twice a year and never grease it. Same number on Pacific Light and Pacific Plus.
Plain bearing (bushing)147 · 1482,6,5,1,4—Bearing collars of the windvane shaft, Delrin, 1 × 20 mm. Numbered 147/148 in the manual’s parts list, the exploded drawing and the Pacific Plus list, but 145/146 in Windpilot’s online Pacific list; the Pacific Light uses 145/146. Say which gear you have when ordering.
Plain bearing (bushing)1141,2,6—Flange sleeves of the windvane axle, two, Delrin, 10 × 15 × 15 mm: the pivot bearings of the vane hanger on axle 113.
Plain bearing (bushing)304 · 3061,2,6,4,5—Sleeve 304 and flange sleeve 306 of the small bevel gear, Delrin, 10 × 15 × 15 mm each. Same numbers on Pacific Light and Pacific Plus.
Plain bearing (bushing)332 · 333 · 3411,2,6,5,4—Pendulum arm bearing collars 332 (1 × 55 mm) and 333 (1 × 40 mm), Delrin, also on the Pacific Plus; bearing washer 341 (1 × 44 × 75 mm) sits on the Pacific’s pendulum axle and is easily lost when the arm comes off. Pacific Light: bearing washers 311 on its axle 310.
Plain bearing (bushing)4101,2,6,4,5—Flange sleeve of the pendulum rudder shaft, Delrin, 5 × 50 × 40 mm. Same number on Pacific Light and Pacific Plus.
Gear set305 · 3251,2,6,4,5—Bronze bevel gears of the 2:1 linkage: small gear 305 on the pendulum arm and large gear 325 (70 × 40 mm, held by countersunk screw 326, M6 × 35). With vane and pendulum upright the arm of 305 points to quarter past twelve; note the position before you take them apart. Pacific, Pacific Light (where 305 is called the pinion gear) and Pacific Plus.
Axle (pivot pin)3271,2,6,5—Bevel gear axle, POM, 30 × 160 mm. Pacific and Pacific Plus.
Top cap3201,2,6,4,5—Red PVC cover over the bevel gears, 75 × 100 mm, with two M4 × 16 slotted screws 321. Same on Pacific Light and Pacific Plus.
Gear set260 · 2611,2,6—Course-setting worm gear 260 (Delrin, 65 × 24 mm) with countersunk screws 261 (M4 × 12, stainless): these small screws are all that hold the windvane shaft, so never lift the gear by the shaft. The manual lists two screws, the online list one. Also on the Pacific Plus.
Adjusting knob2701,2,6—Worm: the red knurled course-setting knob (Delrin, 32 × 88 mm) on bolt 273 (M6 × 75) with Delrin washer 274. The thin remote-control line runs round it in a continuous loop to the cockpit. Also on the Pacific Plus.
Push rod (vane linkage)151 · 1521,2,6,4—Stainless M6 push rod between vane and bevel gears: 151 is 580 mm and 152 is 680 mm long, to suit the windvane shaft; the Pacific Plus takes the 680 mm rod, the Pacific Light its own 150 (M6 × 580). A bent rod can be straightened, but it usually means the pendulum blade is out of balance.
Ball socket158 · 1601,2,6,4,5—Delrin universal joints at the ends of the push rod: upper 158 (30 × 20 mm) and lower 160 (30 × 13 mm, with locknut 161, washers 162 and screw 163, M6 × 20). They must turn freely on the rod. Same numbers on Pacific Light and Pacific Plus.
Axle (pivot pin)1131,2,6—Windvane axle: the M10 × 65 stainless bolt the vane hanger 110 pivots on, with washer 115 and nut 116. If the vane sticks, check this joint first.
Axle (pivot pin)3401,2,6,4,5—Pendulum axle (pendulum arm bolt), aluminium, 44 × 212 mm. Some play here comes with use and does not affect steering, according to Windpilot. Pacific only: the Pacific Light uses 310, the Pacific Plus 370.
Axle (pivot pin)3341,2,6—Set screw of the pendulum arm, M10 × 75 stainless, acting as its axle. The manual allows WD-40 or Teflon spray here, unlike on the Delrin bearings. Also on the Pacific Plus.
Rudder shaft & tube420 · 421 · 4221,2,6,4—Pendulum rudder shaft, 40 mm aluminium tube: 420 is 350 mm, 421 is 450 mm and 422 is 550 mm long, pinned with spring pin 425 (6 × 40). Windpilot supplies the length that suits the boat; the Pacific Light uses 420 and 421 only.
Fastening kit8051,2,6—System retaining bolts, two, M10 × 45 stainless, with washers 806. Undo these two to take the whole gear off for harbour or winter; the bracket stays on the transom.
Mounting bracket800 · 8601,2,6,4—Mounting base (bracket crown) 800, AlMg5, 80 × 90 × 160 mm, with four M12 × 45 side bolts 801, and the four mounting clamps 860 (60 × 40 mm), which turn to follow the transom’s curve and slide along the bracket cheeks for alignment. Pacific; the Pacific Light has base 700.
Mounting bracket8101,2,6—MF0, the standard bracket: a pair of AlMg5 cheeks (45 × 220 × 150 mm) with M12 × 55 bolts 811 and washers 812, for transoms raked between about −20° and +10° and for canoe sterns.
Mounting bracket820 · 825 · 830 · 835 · 840 · 845 · 8501,2,6—Bracket extensions for other sterns: MF1 left/right 820/825 (15 × 220 × 280 mm), MF2 left/right 830/835 (15 × 220 × 360 mm), MF3 840 (pair, 15 × 220 × 430 mm), MF4 845 (pair, 15 × 220 × 500 mm) and the four MF5 arms 850 (50 × 90 × 360 mm, with M8 hardware 851–853) for transom-hung rudders. MF is Windpilot’s mounting flange system, not a model.
Tiller bracket010 · 0158,2,7—Bronze tiller fitting 010 (20 × 24 × 60 mm, two oval-head screws 011) and stainless chain 015 (200 mm). Fit it about 65 % of the tiller length from the aft end; hooking in a different link trims the course, unhooking the chain frees the tiller. Pacific and Pacific Light.
Wheel adapter020 · 030 · 040 · 0508,2,9,10—Wheel adaptor rings, AlMg5: outer rings 020 and 050, inner rings 030 and 040, held to the spokes by three M5 U-bolts 031. It works like a disc brake, so the drum slips when overloaded; fits 5- to 8-spoke wheels with a 10 cm centre opening. Windpilot says owners of Aries, Monitor and Sailomat gears use it too.
Plain bearing (bushing)021 · 0228,2—Delrin bearing washers and liners of the wheel adaptor, two of each (1 × 10 × 148 mm): the surfaces the drum slips on when overloaded.
Clutch lever0518,2—Clamp levers of the wheel adaptor, two, M8 × 35 stainless, with Delrin washers 052: they lock the drum to the disc. Don’t overtighten; on boats up to about 36 ft one lever is usually enough.
Control line0258,2,1,4—Line wound on the wheel adaptor drum, 2.5 m. The steering lines themselves tie to ring nut 345 on the pendulum arm (Pacific Light: 315); moving the ring up or down the arm’s slot trades line travel for force.
Turning block0828,2,7—Two stainless turning blocks at the ends of crossbar 080 (aluminium, 25 × 600 mm, with clamp parts 070/075 and eye bolts 081). The crossbar is needed when the lines leave the gear at more than 30°; standard with MF3 and MF4, optional with the other brackets. The Pacific Light’s crossbar is 060.
Rudder blade670 · 6715,11,12—Pacific Plus only: buoyant foam-filled auxiliary rudder, 330 × 900 mm (670) or 330 × 1200 mm (671), for versions since 2004; until 2004 the same sizes were numbered 660/661. Rotomoulded PE since March 2000, GRP over foam before. Unlike the pendulum blade it stays in the water, so antifoul it.
Plain bearing (bushing)620 · 621 · 6405—Pacific Plus only: auxiliary rudder shaft bearings, that is bearing bush 620 (POM, 10 × 80 × 35 mm) with two rubber O-rings 621 (5 × 80) and bearing flange sleeve 640 (POM, 60 × 97 × 45 mm).
Adjusting knob523 · 5135,12—Pacific Plus only: star grip 523 (M12, DIN 6336) that locks the coupling to the auxiliary rudder, on eye bolt 520 with spacer 522 and washer 521, and the three guide pins 513 (12 × 40, DIN 1472). Keep the threads lubricated and check now and then that the pins are seated, as engine vibration can work them loose.
Emergency rudder1100 · 110113,14—SOS Rudder blade, foam-filled, 330 × 900 mm (1100) or 330 × 1200 mm (1101). The SOS Rudder Pacific hangs on the existing Pacific bracket with adapter 1070; blind segment 1090 closes the lower bracket in normal use. The SOS Solo is the version for boats without a Windpilot.

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

Service intervals

TaskInterval
Clean gear linkage & bearingsTwice a year: clean salt and oil out of the bevel-gear linkage and its main bearing bush 328; never grease it2
Fresh-water washRinse with fresh water regularly. After every long trip give it a thorough soak and rinse: Windpilot’s tip is to soak it with salt water for about 15 minutes on a damp evening, then rinse with fresh water2
LubricationNever grease or oil the Teflon, POM and Delrin bearings. Every so often a drop of washing-up liquid or silicone, Teflon or WD-40 spray on the worm gear 260/270; WD-40 or Teflon spray on axle 334 and on the push-rod universal joints if they stick2
LubricationPacific Plus: keep the coupling threads (star grip 523, spacer 522, washer 521) lubricated with WD-40 or lanolin, spray the guide pins 513 regularly and check that they are seated12
Season checkRegularly: check the transom bolts, and never sail with bolts you know are loose, as the whole gear can be lost. Every time you use it: check that the universal joints 158/160 turn freely on the push rod2
Corrosion protectionWax the tubes now and then. Castings and tubes are assembled with lanolin, so they should still come apart after years2
Storage / winterisingWhen not in use: take the vane off and lift the pendulum or remove the gear (two bolts 805). If it will stand idle, cover or remove it: in the lift-up position, rain washes dirt down into the bearings2

From Windpilot’s Pacific manual (current edition) and the Pacific Plus manual. Windpilot gives no hour or mile figures: apart from the twice-yearly clean of the bevel gears and bearing 328, its advice says “regularly” or “every so often”.

Specifications

TypeServo-pendulum wind-vane gear with a horizontally pivoted vane: through a 2:1 bronze bevel-gear linkage, which also damps yaw, the vane turns the pendulum blade, and the swinging arm pulls two lines at deck level to the boat’s own tiller or wheel. Not an emergency rudder by itself (the SOS Rudder add-on is)15,2
VersionsPacific: tiller or mechanical wheel, aft cockpit. Pacific Light: smaller servo-pendulum for tiller boats up to 8.5 m (27 ft) and 2500 kg. Pacific Plus I (up to 12 m / 40 ft, 13000 kg) and II (up to 18 m / 60 ft, 30000 kg): the pendulum drives its own buoyant auxiliary rudder through a gear coupling while the main rudder is locked; for mechanical or hydraulic wheels, aft or centre cockpit, and usable as an emergency rudder. SOS Rudder: emergency rudder, as SOS Pacific on the existing Pacific bracket or as SOS Solo for boats without a Windpilot; size I under 40 ft, size II under 60 ft16,17,14
Years builtCurrent die-cast design since 1998, still in production. Sand-cast aluminium Pacific and Pacific Plus 1985–1998, with a different two-digit part numbering; hand-built stainless Windpilot gears from 196818,19
SizesUp to 18 m (60 ft) and 25000 kg (55000 lb) according to Windpilot’s product page; Windpilot’s own SOS Rudder article says under 70 ft15,20
WeightPacific 20 kg (44 lb); Pacific Light 13 kg; Pacific Plus I/II 45/50 kg on the product page, but 40/44 kg in Windpilot’s 1999 brochure and 75 kg in an advice article on its blog; SOS Rudder 23–30 kg15,16,17,21,22,14
ControlTiller: bronze fitting and chain. Mechanical wheel: slipping drum adaptor for 5- to 8-spoke wheels, designed for wheels of about 60 cm with about 2.5 turns lock to lock. Hydraulic and other wheel systems only through the emergency tiller with the wheel gear disconnected from the quadrant, otherwise the Pacific Plus. Course set by hand or from the cockpit with a thin line looped round the worm. A pin on the vane hanger takes a push-rod tiller pilot (Autohelm, Navico/Simrad), which then steers through the pendulum2,9
MountingBracket chosen for the stern (MF is Windpilot’s flange system, not a model): MF0 standard, for about −20° to +10° of transom rake and canoe sterns; MF1 extreme transoms and short platforms (about −40° to +25°); MF2 very extreme sterns and larger platforms; MF3 sugar-scoop sterns with the platform about 50 cm above the waterline, fixed to its horizontal face; MF4 platform less than 50 cm above the waterline; MF5 transom-hung rudders such as Colin Archer types2
MountingIn the centre of the transom (at most 10 cm off centre), about 10 cm below deck level, pendulum shaft 10° aft of vertical. Blade bolt 435 about 5–10 cm above the static waterline in the manual’s detailed section, 10–20 cm in its quick guide. Steering-line ring 345 at deck level. Holes drilled 9 mm, then 10.5 mm; bolts bedded in Sikaflex over 60 mm plastic discs. No transom reinforcement needed except on sandwich hulls, where the core is replaced with wood locally2
DimensionsFrom Windpilot’s dimension drawing: windvane 900 mm high (900 × 190 mm), vane mast to bracket 800 mm, bracket to blade bolt 700 or 900 mm, blade bolt 100 mm above the waterline, blade 700 mm below it. Bolt pattern 180 × 164 mm on MF0, 215 × 164 mm on MF1 to MF423,2
Max pull / working load20–25 cm (8–10 in) of line travel and up to 200 kg (440 lb) of pull on the steering. The lines should leave for the first blocks at no more than 30°, otherwise fit the crossbar. The pendulum swings about 25° each side and lifts 170° clear of the water on a line, which only works below about 2 kn2
MaterialHard-anodised, seawater-resistant AlMg5 aluminium, low-pressure die-cast and CNC-machined; linkage parts in silicon aluminium bronze; stainless push rod; POM and PTFE bearings; 6 mm AW100 marine-ply windvane3
LubricationBearings of Teflon (PTFE), POM and Delrin throughout: never oil or grease them, because grease and seawater set solid. WD-40 or Teflon spray only where the manual allows it: axle 334, the push-rod universal joints and the worm gear2
PredecessorHand-built stainless gears from 1968: Nordsee vane gears, the Atlantik III and IV auxiliary-rudder gears (until 1984) and early Pacific servo-pendulums. Then sand-cast aluminium: the Caribic auxiliary rudder (1985–87, successor to the Atlantik) and the Pacific and Pacific Plus of 1985–9818

Good to know

  • Never lift or carry the gear by the windvane shaft: only the two small screws 261 hold it on the worm gear. Lift it by the casting at the foot of the shaft (250) and the pendulum arm, and tie on a safety line before fitting or removing it.2,1
  • If the gear feels stiff, look at bearing 328 in the bevel-gear linkage first. Before you take the gears apart, note their position: with vane and pendulum upright, the arm of the small gear points to quarter past twelve.2
  • Lost the pendulum blade? A plain plank of about 120 × 900 × 20 mm gets you home, as long as roughly a fifth of its area sits ahead of the shaft. If the blade starts steering the vane instead of the other way round, too much of it is forward.2
  • Tie the steering lines with knots, not splices, so you can turn them end for end to spread the wear. Fix two of the turning blocks to the boat with thin cord (about 3 mm) as a deliberate breaking point in case the system is overloaded.2
  • Buying second-hand: every Windpilot is configured for its first boat (bracket, rudder-shaft and vane-shaft length, tiller or wheel), and used gears rarely come with the lines, blocks and shackles. Windpilot offers to check from a photo and your boat type whether a unit fits, and warns that neglected gears can have years of salt and dirt in the bearings.24
  • Part numbers changed with the 1998 redesign: the sand-cast Pacific of 1985–98 has its own two-digit numbers, shown only on Windpilot’s pre-1998 drawings. Tell Windpilot which version you have when you order.19

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Sources

  1. windpilot.com/n/wind/en/serv/manu/stupacen
  2. windpilot.com/n/pdf/2020/Pacific_EN.pdf
  3. windpilot.com/n/wind/en/prod/stan/
  4. windpilot.com/n/wind/en/serv/manu/stuligen
  5. windpilot.com/n/wind/en/serv/manu/stupluen
  6. windpilot.com/n/wind/en/serv/manu/zeipacific
  7. windpilot.com/n/pdf/2020/Pacific_Light_EN.pdf
  8. windpilot.com/n/wind/en/serv/manu/stuzuben
  9. windpilot.com/n/wind/en/prod/zube/
  10. windpilot.com/blog/en/tec-news/production-2/production/
  11. windpilot.com/n/wind/en/comp/prod/
  12. windpilot.com/n/wind/en/serv/manu/manpluen
  13. windpilot.com/n/wind/en/serv/manu/stusosen
  14. windpilot.com/n/wind/en/prod/sosr/
  15. windpilot.com/n/wind/en/prod/paci/
  16. windpilot.com/n/wind/en/prod/lite/
  17. windpilot.com/n/wind/en/prod/plus/
  18. windpilot.com/blog/en/tec-news/typology-and-history/
  19. windpilot.com/n/wind/en/serv/manu/zeipacific98
  20. windpilot.com/blog/en/tec-news/sos-rudderless/
  21. windpilot.com/n/pdf/WP.PDF
  22. windpilot.com/blog/en/tec-news/advice/pacific-pacific-plus/
  23. windpilot.com/n/wind/en/serv/manu/flapaccm
  24. windpilot.com/blog/en/tec-news/pre-loved/

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