The essential in 30 seconds
- ≤ 12 m / 7.5 t : linear electromechanical cylinder is sufficient. Simple, low maintenance, material cost €1,500–2,200. Brands: Garmin GHP 12 Type 1, Raymarine Type 1, Lecomble & Schmitt MK1.
- 12–15 m / 7.5–13.5 t : Type 2 electromechanical may still work for cruising, but hydraulic is recommended for rough seas and offshore. Material cost €2,200–3,500.
- ≥ 15 m / 13.5 t or racing : hydraulic is mandatory. Power, speed, and reversibility are essential. Brands: B&G hydraulic T1, T2, Lecomble & Schmitt MK2/MK3, Simrad DD15.
- 3 key criteria to decide: thrust force (minimum 1,000 N/t displacement), rudder speed (3–5 s/° in cruising, < 2 s/° in racing), reversibility barman ↔ autopilot (hydraulic wins).
- Full refit budget: electromechanical €4,000–6,500 excluding VAT installed (cylinder + computer + sensors + labor), hydraulic €6,500–12,000 excluding VAT.
The rudder cylinder is the force actuator of the autopilot. It converts an electrical signal into rudder movement. Two technology families coexist: electromechanical (electric motor + worm gear) and hydraulic (pump + cylinder). Choosing one or the other determines 10 years of use, refit budget, and the autopilot’s relevance in conditions.
If you are looking for maintenance on your existing cylinder, see our article on rudder cylinder maintenance. For choosing a complete autopilot (cylinder + computer + sensors), see B&G vs Raymarine autopilot for 40–50 foot sailboats. This article is dedicated solely to the choice of cylinder technology.
The two families: electromechanical vs hydraulic
Linear electromechanical
An electric motor turns a worm gear that pushes or pulls a rod. The rod is mechanically connected to the rudder quadrant. Everything is integrated into a single housing: cylinder = finished product, assembled and forgotten.
- Brands on Skysat: Garmin GHP 12 Type 1 (€1,916), Type 2 (€2,191), Raymarine Type 1/2/3, Lecomble & Schmitt MK1/MK2/MK3 (currently not distributed by Skysat).
- Typical range: sailboats 8–15 m, up to 13.5 t displacement, rod stroke 250–350 mm.
- Force: 7.5–13.5 kN depending on model.
Hydraulic
An electric pump pressurizes oil in a cylinder attached to the rudder quadrant. The pump can be separate from the cylinder (typical for small to medium sailboats) or integrated into a direct drive system (yacht ≥ 50 feet, racing).
- Brands on Skysat: B&G hydraulic T1 12V (€1,700), T2 24V (€2,070), Simrad DD15 (€1,962), Garmin SmartPump v2 (€2,899), Lecomble & Schmitt MK1/MK2/MK3 hydraulic (available on special order).
- Typical range: sailboats 11–22 m, offshore cruising large size, multihulls.
- Force: 13.5–22 kN+ depending on configuration.
Technical comparison: 6 criteria that determine the choice
1. Thrust force
Workshop rule of thumb: 1,000 N per ton of displacement at full load in standard cruising. For offshore cruising or heavy offshore in rough seas, increase to 1,500 N/t.
- 8 t cruising sailboat → minimum 8 kN cylinder → Type 1 electromechanical or light hydraulic.
- 14 t offshore cruising sailboat → 14 kN cylinder → Type 3 electromechanical or T2 hydraulic.
- 20 t racing sailboat → 30 kN cylinder → large-stroke hydraulic (DD15, MK3+).
2. Rudder speed (degrees per second)
The speed at which the cylinder can correct a heading deviation. Critical in rough seas and racing.
- Typical electromechanical: 3–6 s for full rudder (35° each side).
- Typical hydraulic: 2–4 s for full rudder.
- Racing direct drive hydraulic (Simrad DD15, Lewmar GP): 1–2 s for full rudder.
3. Electrical consumption
#1 or #2 consumer in the autopilot’s 24-hour energy balance (see our article on sizing lithium banks).
- Electromechanical at rest: 0.1 A (just logic power).
- Electromechanical in correction: 1–3 A (Type 1) to 3–6 A (Type 3).
- Hydraulic at rest: 0.2–0.5 A (standby pump).
- Hydraulic in correction: 3–8 A peak, but shorter cycles.
Over 24 hours in rough seas, total consumption is roughly equivalent between the two technologies — hydraulic consumes more in peaks but cycles faster and thus for less time.
4. Reversibility (barman ↔ autopilot ↔ barman)
The cylinder’s ability to free the rudder when the autopilot is disengaged.
- Linear electromechanical: the worm gear mechanically locks the rudder even with autopilot off. Creates a "braking" sensation for the helmsman, who must push against the internal resistance of the cylinder. Major drawback in racing and short-handed sailing.
- Hydraulic with automatic bypass: autopilot off = open valves = 100% free rudder. The helmsman takes over without any resistance. This is the criterion that pushes 90% of racing programs toward hydraulic systems.
5. Maintenance and lifespan
No major difference if installation is correct. See our rudder cylinder maintenance guide.
- Electromechanical: 1 greasing of axes + rod end per season, bronze bushing check every 500 h, typical lifespan 10–15 years.
- Hydraulic: annual oil level and quality check, drain every 5 years, typical lifespan 12–18 years.
- Racing direct drive hydraulic: more precise maintenance (seals, pressure, solenoid valve), lifespan 8–12 years in intensive racing use.
6. Footprint and installation
- Electromechanical: 1 compact housing to mount between structural frames and rudder quadrant. Installation in 4–8 h in workshop.
- Hydraulic: 2 components (pump + cylinder) connected by high-pressure hoses. Installation 8–16 h in workshop (hose runs + system bleeding).
- Racing direct drive hydraulic: complex integration on rudder shaft, installation 16–32 h.
Linear electromechanical cylinder — details and brands
The historic technology of sailboat pleasure boating since the 1980s. Widely adopted because it is the simplest product to integrate in a refit.
Garmin GHP 12 (linear cylinders)
Skysat distributes the Type 1 (€1,916) for sailboats ≤ 11 m / 7.5 t and the Type 2 (€2,191) for sailboats 11–15 m / 7.5–13.5 t. The cylinder is controlled via a Reactor 40 computer and a GHC 50 display.
Raymarine Type 1/2/3
Historic Raymarine Evolution range. Type 1 ≤ 11 m, Type 2 11–15 m, Type 3 15–22 m. Compatible with Raymarine EV-100/EV-200/EV-400 computers. Skysat distributes the ACU computer and Raymarine accessories; the cylinder itself is sometimes available on special order.
Lecomble & Schmitt MK1/MK2/MK3
Historic French manufacturer (Vendée). Very common on new Bénéteau/Jeanneau sailboats. Rod stroke 250 mm (MK1), 300 mm (MK2), 350 mm (MK3). Force 7.5 kN to 22 kN. Skysat does not distribute standard but can source for refit projects on request.
Hydraulic cylinder — details and brands
Mandatory technology beyond 15 m, strongly recommended for offshore racing from 10 m. Pump + cylinder + bypass + pressure gauge architecture.
B&G hydraulic T1/T2
Skysat distributes the B&G T1 12V (€1,700) and T2 24V (€2,070). Compatible with NAC-3 Navico computer (€1,649). For sailboats 11–18 m, comfortable offshore cruising, and Category B/C racing.
Simrad DD15 (Direct Drive 15 kN)
The DD15 (€1,962) is a direct drive hydraulic power unit for sailboats 15–22 m racing/offshore cruising. Force 15 kN, full rudder speed 1–2 s. Immediate reversibility. Requires dedicated rudder shaft for integration.
Garmin SmartPump v2
The SmartPump v2 (€2,899) hydraulic pump is compatible with existing hydraulic systems (third-party cylinders). Controlled by the Garmin Reactor 40 hydraulic GHC 50 computer (€2,080). Good choice for boats already equipped with an original hydraulic cylinder (e.g., Bénéteau Yacht line yachts).
Lecomble & Schmitt hydraulic MK1/MK2/MK3
Separate pumps and cylinders, hydraulic equivalents of the L&S electromechanical range. Widely used in French offshore racing (IMOCA, Class40). Available on special order via Skysat.
Comparison table by size and program
| Sailboat | Program | Recommended tech | Reference model | Cylinder force | Excluding VAT installed budget |
|---|---|---|---|---|---|
| ≤ 10 m / 5 t | Weekend coastal | Electromechanical | Garmin Type 1, Raymarine Type 1, L&S MK1 | 5–8 kN | €3,500–4,500 |
| 10–12 m / 5–7.5 t | Coastal + 1–2 weeks summer | Electromechanical Type 1 | Garmin Type 1 (€1,916) + Reactor 40 | 7.5 kN | €4,000–5,500 |
| 11–13 m / 7.5–10 t | Offshore cruising | Electromechanical Type 2 OR light hydraulic | Garmin Type 2 (€2,191) OR B&G T1 (€1,700) + NAC-3 | 10–13 kN | €5,500–7,500 |
| 13–15 m / 10–13.5 t | Offshore + transatlantic | Hydraulic | B&G T2 24V (€2,070) + NAC-3 | 13.5 kN | €7,000–9,500 |
| 15–18 m / 13.5–18 t | Offshore comfort | Hydraulic T2/T3 | L&S MK2 hydraulic + NAC-3 | 15–18 kN | €8,500–12,000 |
| 15–22 m / 13.5–22 t | Offshore racing IMOCA/Class40 | Direct drive hydraulic | Simrad DD15 (€1,962) + NAC-3 + Madintec | 15–22 kN | €12,000–18,000 |
| ≥ 20 m yacht | Yacht with CZone | External pump hydraulic + third-party cylinder | Garmin SmartPump v2 + Reactor 40 GHC 50 | 15–22 kN | €10,000–15,000 |
Example figures: sailboat 35 / 45 / 55 feet
35-foot sailboat (10.5 m) / 6.5 t — coastal cruising and 2 weeks offshore per year
- Recommended choice: electromechanical Type 1 (simplicity outweighs power margins).
- Skysat solution: Garmin Type 1 (€1,916) + Reactor 40 Compact starter pack (€1,579) including computer + GHC 50 + sensors.
- Total installed budget: €4,200–5,000 excluding VAT (cylinder + pack + 8 h labor).
45-foot sailboat (13.5 m) / 11 t — offshore cruising + 1 transatlantic every 5 years
- Recommended choice: B&G hydraulic T1, for reversibility barman ↔ autopilot (short-handed sailing) and margin in rough seas.
- Skysat solution: B&G hydraulic T1 12V (€1,700) + NAC-3 (€1,649) + Precision 9 (€533) + RF25N (€319).
- Total installed budget: €6,500–8,000 excluding VAT (cylinder + computer + sensors + 12 h labor + oil).
55-foot sailboat (16.8 m) / 16 t — offshore racing + crewed transatlantic
- Recommended choice: direct drive hydraulic with premium racing computer (Madintec compatible).
- Skysat solution: Simrad DD15 (€1,962) + NAC-3 (€1,649) + sensors + Madintec MAD Controller (€2,550) racing upgrade.
- Total installed budget: €11,000–15,000 excluding VAT (cylinder + computer + sensors + Madintec + 20 h labor).
5 common mistakes when choosing
Cylinder choice mistakes — seen in Skysat workshop
- Undersizing due to optimism. The sailboat manufacturer lists 7.5 t displacement, so we choose Type 1. Except the boat sails with 800 L of water + fuel + crew + 200 kg of gear = 9.5 t real displacement. The Type 1 strains, overheats, and ends up failing. Always size based on actual sailing weight, not manufacturer weight.
- Choosing electromechanical to "save money" on a 15+ m offshore sailboat. Type 3 electromechanical costs ~€1,000 less than T2 hydraulic. Except in rough seas with 25 knots, the electromechanical saturates, the autopilot drops out, and you’re hand-steering 18 h/day. The real savings are negative.
- Hydraulic without automatic bypass. If the hydraulic system lacks automatic bypass valves (as in some older kits), the rudder remains locked even with autopilot off. The helmsman struggles, the crew complains. Always verify bypass presence at purchase.
- Choosing an incompatible brand with the existing ecosystem. The boat has a Raymarine Axiom chartplotter. The client buys a Garmin Reactor 40 autopilot to save money. Result: no autopilot control from the Axiom, Garmin remote required at the cockpit, two parallel ecosystems. Choose an autopilot from the same brand as the main chartplotter — or an open system like Madintec that talks to everything.
- Undersized hydraulic pump relative to the cylinder. A 15 kN cylinder with an undersized pump = slow correction, the autopilot lags, oscillations. Always pair pump and cylinder from the same manufacturer or validated together by the installer.
FAQ — Choosing your sailboat cylinder
Can an existing electromechanical system be converted to hydraulic?
Yes, but installation is heavy: new hydraulic cylinder, new pump, high-pressure hose runs, system bleeding, possible rudder quadrant modification. Allow 16–24 h workshop labor + €2,500–4,000 material depending on configuration. Only relevant if the boat’s program evolves significantly (cruising → racing, or upgrade from coastal to offshore after insufficient experience).
My sailboat already has a Lecomble & Schmitt cylinder — can I control it with a Garmin or B&G computer?
Yes, the L&S cylinder is mechanical (or hydraulic) — it accepts any compatible control signal. The computer + rudder angle sensor + compass pairing can come from any ecosystem. Verify the L&S existing electrical interface (voltage, max current, position feedback type) and adapt the computer accordingly. The Madintec MAD Controller is designed to drive almost any cylinder on the market.
What’s the difference between reversible and non-reversible hydraulic?
Reversible hydraulic = double-acting pump (can push or pull the cylinder), requires bypass valves to free the rudder. Non-reversible hydraulic = single-acting pump, the rudder is mechanically linked pump-cylinder when autopilot is off (permanent brake). Always prefer reversible with automatic bypass for safety and helmsman comfort. All modern B&G/Garmin/Raymarine systems are reversible by default.
Dry or wet hydraulic pump?
Dry in 99% of cases. The pump is mounted in a ventilated technical locker near the cylinder. Wet pump (immersed in the oil reservoir) exists on some older systems but requires a sealed reservoir and full disassembly for maintenance. If refitting, switch to a modern dry pump.
Rudder cylinder vs tiller quadrant: compatible?
Yes in almost all pleasure boat configurations. The cylinder drives the tiller quadrant (the part that transmits the rudder rotation to the rudder blade) via a link arm. Compatibility depends on the quadrant’s rotation angle (typically 70° total, ±35° each side), cylinder stroke, and available space. Always verify with an on-site workshop measurement before purchase.
Should we plan a backup cylinder for offshore?
Not a backup cylinder, but a backup strategy: emergency tiller / windvane (Aries, Hydrovane, Windpilot) for sail, or drogue / demountable tiller for power. The electric cylinder is a sensitive system — on a transatlantic, plan at least a return cable to the manual tiller with the ability to disconnect the cylinder-quadrant coupling (typically a demountable pin). See our rudder cylinder maintenance guide for signs of impending failure.
What wiring should be planned between computer and cylinder?
Wire gauge calculated on max current of cylinder + 30% margin. Electromechanical Type 1 (5–10 A): 2 × 4 mm² cable for 3–5 m runs. Type 2–3 (10–15 A): 2 × 6 mm². Hydraulic pump (8–15 A peak): 2 × 6 mm² minimum, up to 2 × 10 mm² for high-power pumps. Always protect with a fuse calibrated to the cylinder’s nominal current (not peak) + 50%, accessible from the dashboard for quick reset in case of incident.
Skysat distributes B&G, Garmin, Raymarine, Navico, Madintec, and Simrad brands. This article reflects our autopilot installation experience on over 120 sailboats between 2018 and 2026, in cruising and offshore racing. 2026 HT prices are indicative distributor prices, excluding specific wiring and excluding mechanical adaptation to the existing tiller quadrant.
