The essentials in 30 seconds
- Most pilot failures we take in at the workshop come from the drive, not the electronics. Salt on the rod, joint play, tired oil, worn brushes: four avoidable causes.
- Sizing: follow the manufacturer's chart on loaded displacement. Verified references: Raymarine Type 1 = ≤ 11 t (295 kg thrust), Type 2 = ≤ 15 t (480 kg); Garmin Type 1/2/3 = 13/21/35 t (400/730/1,080 kg).
- 5 signs of a struggling drive: overheating, motor noise, delayed response, abnormal draw, course weaving.
- A drive gives no warning before it fails — unless you know how to listen. Full checklist below; workshop test bench if in doubt.
Contents
Your autopilot is your best crew member — but its "brain" (the course computer) is useless without its "muscle" (the drive). Whether hydraulic (Lecomble & Schmitt, Hy-Pro) or electromechanical (Raymarine or Garmin Type 1/2, Jefa), the steering drive is a wear part under colossal loads — and the most neglected item at winterising time. Here is our technicians' checklist to avoid ending up on the emergency tiller in the middle of Biscay.
The 5-point workshop checklist
1. The nemesis: salt on the rod
The number-one cause of hydraulic leaks. The drive lives in a damp, salty lazarette. Salt crystallising on the chromed rod acts like sandpaper on the lip seals at every stroke. The expert move: rinse the rod with fresh water regularly, wipe with a clean cloth. Do not use thick grease, which traps dust and salt — a dry PTFE spray or a lightly oiled cloth, nothing more.
2. Hunting mechanical play (ball joints and mounts)
A pilot that "knits" or over-draws is often a badly mounted pilot. The test: pilot disengaged, grab the drive body firmly and shake it sideways and vertically. A "clack-clack" = dead ball joint or loose bolt. Danger: 1 mm of play becomes violent shocks in a seaway, up to tearing the mount off — we have seen it too often. Retighten or replace immediately.
3. Hydraulics: the oil's colour does not lie
Level between min and max — a drop always means a leak (absorbent paper under the fittings to locate it). Black oil: seals are breaking down. "Mayonnaise" oil: water has entered. Either way: full bleed and seal replacement.
4. The blind spot: motor brushes
The "silly" failure that comes after 3,000-4,000 hours: the DC motor's brushes wear, the motor misfires then stops. If your power unit is over 10 years old or has a circumnavigation behind it, inspect brush length — lots of black dust inside means it is time to change them.
5. Clutch and belt (mechanical drives)
On Raymarine-style electromechanical linear drives, transmission goes through an internal belt. Motor running but helm not moving (or slipping under load): do not blame the course computer — it is the belt gone slack or the clutch getting tired.
The last word. A drive gives no warning before failing — unless you listen: a new noise, a squeal, a trace of oil. In doubt before the season, remove it and send it to the workshop: full bench test (pressure, tightness, current draw) to validate its reliability.
Sizing, by the manufacturer's chart
Size on full-load displacement (crew, water, fuel, gear — often 20-25 % above the builder's figure), following the manufacturer's chart. In steep seas or racing, take the category above.
| Drive | Computer | Max displacement | Thrust | Stroke |
|---|---|---|---|---|
| Raymarine Type 1 | ACU-200 | 11 t | 295 kg | 300 mm |
| Raymarine Type 2 | ACU-400 | 15 t | 480 kg | 300 mm |
| Garmin Type 1 | Reactor 40 | 13 t | 400 kg | — |
| Garmin Type 2 | Reactor 40 | 21 t | 730 kg | — |
| Garmin Type 3 | Reactor 40 | 35 t | 1,080 kg | — |
Beyond that, or for heavy helms: hydraulic rams (Lecomble & Schmitt, Hy-Pro) and direct drives (Jefa, Simrad DD15 for 30-45 footers). Technology choice is detailed in our hydraulic vs electromechanical comparison — and since September 1st, the brushless Garmin SmartDrive (≤ 15 t, 476 kg) joins the family. Sources: current Raymarine and Garmin documentation, Sept. 2026.
5 signs of an undersized drive
Several of these symptoms together mean your drive works beyond its comfort zone — check the sizing before blaming the course computer.
1. Overheating: the drive is burning hot after 30 minutes of piloting in an established 15 knots. Normal with a heavy helm in a seaway; abnormal in standard cruising.
2. Unusual motor noise: continuous humming, high-pitched whine under load — the motor draws beyond its specification.
3. Delayed response: a perceptible lag between order and rudder movement, felt at the helm. Check gain settings before concluding.
4. Abnormal draw: the pilot pulls well above its datasheet as a 24 h average — a shunt measurement confirms it.
5. Course weaving: the boat oscillates either side of the route instead of holding the line, especially downwind: the pilot corrects too late.
Field maintenance
The workshop quick list: visual inspection at every haul-out (tightness, corrosion, joint play); grease pins and clevis with marine grease once or twice a season; torque checks to the manufacturer's values; full rudder-angle test on the hard, quadrant freed — it must reach ±30-35° without binding or knocking; bush checks every 500 h of piloting.
FAQ — Sailboat steering drives
How do I know if my drive is undersized?
Five field signs: overheating after 30 minutes in moderate conditions, unusual motor noise, a perceptible lag at the helm, current draw well above the datasheet (shunt measurement), and course weaving — the boat oscillates instead of holding the line. One sign alone: check mounting and pilot settings first. Several combined: check the sizing against loaded displacement.
Is there an equivalence between Raymarine Type 1/2/3 and Lecomble & Schmitt?
There is no direct equivalence: Raymarine Types are electromechanical linear drives rated by displacement (Type 1 ≤ 11 t, Type 2 ≤ 15 t), while Lecomble & Schmitt builds hydraulic rams with integrated electric bypass (LS40ST/Newave range), sized by pump-cylinder pairing. You compare complete systems on the boat's loaded displacement, not references one-to-one.
How much thrust does my sailboat need?
Follow the manufacturer's chart on full-load displacement (water, fuel, crew, gear — often 20-25 % above the builder's figure). Verified references: Raymarine Type 1 = 295 kg of thrust for ≤ 11 t; Type 2 = 480 kg for ≤ 15 t; Garmin Type 1/2/3 = 400/730/1,080 kg for 13/21/35 t. In steep seas or racing, take the category above.
Hydraulic or electromechanical?
Electromechanical linear: simpler to install, sufficient for most cruising sailboats — charts cover up to 15-35 t depending on model. Hydraulic: the choice for heavy helms, big displacements and crews that hand-steer a lot (perfectly free helm when disengaged thanks to the bypass). Full detail in our hydraulic vs electromechanical comparison.
How often should a steering drive be serviced?
Visual inspection at every haul-out (tightness, mounts, corrosion). Grease pins and ball joint with marine grease once or twice a season. Check joint play and bushes every 500 h of active piloting (3-5 years in typical cruising use). Full rudder-angle test on the hard at least every 2 years.
