B&G vs Raymarine autopilot for 40-50 foot sailboat: 2026 technical guide

By Pol Conin, Digital Manager. Article based on installations conducted by our engineering department between 2021 and 2026.

On a 40-50 ft sailboat, choosing an autopilot is rarely a brand choice. It’s a program choice: what you do with the boat dictates the algorithm, and the algorithm dictates the computer. The hardware follows. At this size, we’re in the segment where both ecosystems — B&G NAC-3 and Raymarine Evolution — are perfectly credible. Neither is ridiculous. Neither is universally better.

This article summarizes what we’ve learned by regularly equipping both families over the past five years, on about sixty sailboats in this range. The goal isn’t to crown a winner: it’s to give you the decision grid we use in our engineering department. We distribute both brands. We state this honestly. That doesn’t prevent us from having clear preferences depending on the case.

Understanding autopilot architecture (the 3 minimum components)

Before comparing two ecosystems, you must understand that autopilot is a catch-all term. An autopilot isn’t a single box. It’s at least three distinct components that communicate.

1. The computer (computer / CPU)

This is the brain. It receives as input the helmsman’s command (heading, wind angle, ground track), sensor data (compass, accelerometer, speed, wind transducer), and outputs the command to send to the ram. It’s the component that contains the brand-specific algorithm. At B&G, the NAC-3 or NAC-2 controls the drive based on the required electrical power. At Raymarine, the EV-1 contains the 9-axis AHRS and route computer; the ACU provides the power electronics that control the drive.

It’s also this component that contains — or connects to — the inertial measurement unit. The quality of the compass + IMU directly determines the quality of the control loop, especially in rough seas.

2. The control head (display)

This is the user interface. It’s through this that you engage the autopilot, switch from heading mode to wind mode, adjust gains, and read the rudder angle. At B&G: Triton 2 Pilot, Zeus Touch (integrated in the MFD), H5000 Graphic Display. At Raymarine: p70s or p70Rs, Axiom (integrated in the MFD), i70s for readout.

At this boat size, you almost always have at least two control heads: one near the helmsman, one at the nav station. This is a real ergonomics issue we address in the pre-project phase.

3. The ram (drive unit / linear ram)

This is the muscle. It receives the command from the computer and moves the rudder stock (via the quadrant or directly) or the tiller. On 40-50 ft boats, you’re almost exclusively dealing with hydraulic rams or electromechanical linear drives sized for the boat class (Type 1, Type 2, Type 3 at Raymarine; equivalent classes at Lecomble & Schmitt on the B&G side, which is a major OEM supplier in this segment).

An undersized ram is the leading cause of autopilots that "zigzag" in beam seas. And it’s a recurring trap: we address it further down.

For more on rams, see our dedicated guide: Sailboat autopilot ram: choosing, installing, maintaining. (additional article)

Size before comparing brands

The B&G vs Raymarine debate comes after a step too many projects skip: determining the system class your boat requires. Four inputs for the calculation — none of which boil down to length:

• Actual loaded displacement — a Pogo 12.50 and a Garcia 12 don’t demand the same ram, at equal length.
• Type of steering — wheel with cables, hydraulic steering, direct tiller: each case changes the attack point and torque required.
• Rudder torque under the most demanding predictable conditions — this dictates the ram class, and the ram then dictates the power electronics (ACU at Raymarine, NAC-2/NAC-3 based on power at B&G).
• Program — size for the intended offshore passage, not for Sunday outings (see the field case below).

What you can often keep in a refit: a recent, correctly sized hydraulic ram (integrable on a case-by-case basis via interface — never "plug and play"), the NMEA 2000 backbone and its sensors. What follows the chosen ecosystem: the computer, power electronics, and control heads. The exact breakdown of what can be kept is part of the pre-study.

The ecosystems: B&G NAC-3 and Raymarine Evolution

B&G: racing heritage

B&G has a clear history — offshore racing. The brand historically equips IMOCA, Class40, Ultim, and most high-end performance cruising sailboats for twenty years. The NAC-3 is the direct evolution of an ACP lineage started at B&G in the 1990s and refined with every Olympic cycle and Vendée Globe.

Its philosophy: fine control loop, deep integration with the H5000 system (which produces extremely precise wind/speed/race data), and strong compatibility with professional routing software like Expedition. If you already have an H5000, the NAC-3 is almost always the logical next step. If you’re starting from scratch, it’s an investment that makes sense for a performance-oriented program — including fast cruising.

Raymarine: the pragmatic path

Raymarine has a different philosophy: a broader public ecosystem, easier to implement, better supported internationally, natively integrated into Axiom MFDs with a renowned touchscreen interface. The Evolution line is based on an EV-1 that combines a 9-axis AHRS and route computer. The ACU is then chosen based on the steering type, ram capacity, and drive: boat length alone isn’t enough.

This is the ecosystem found on most recent Beneteau, Jeanneau, and Hanse sailboats straight from the yard. It matters: if your 40-50 ft sailboat is a Sun Odyssey 410, an Oceanis 461, or a Hanse 458, you probably already have Raymarine wired in. Reconfiguring everything to B&G isn’t absurd, but it’s not neutral in terms of budget.

Technical comparison: B&G NAC-3 vs Raymarine Evolution

The table below summarizes the main differences we use in our engineering department. Figures marked with an asterisk are those I prefer you validate with the distributor list price on the day you request a quote — they change with each price revision.

*Conditions subject to change: re-verify at quote time. Up-to-date material prices are in the pilot comparison tool and on product pages — we don’t lock prices in the article.

See also: our autopilots in distribution. And for product pages, the B&G / Navico NAC-3 computer and the Raymarine Evolution (p70Rs + ACU-200, Type 1) autopilot, an example Type 1 kit whose sizing must be verified for each boat.

Quick read of the table

Three lines deserve comment:

• Compass / IMU: B&G uses a compatible heading sensor, e.g. the Precision-9, and shares data over NMEA 2000. Raymarine integrates the AHRS and route computer in the EV-1.
• Sailing routing: if you run Expedition, the H5000 is the natural partner. If you’re on Adrena for amateur racing, both ecosystems work honestly, with a slight edge for B&G via H5000.
• Customization: the NAC-3 exposes more low-level parameters to advanced users. This is an asset in racing/regattas, but also a trap in cruising (see common errors below).

Verdict by sailing program

Here’s how we guide clients in pre-study.

Comfortable offshore cruising (family offshore passage, Mediterranean + Atlantic program)

Raymarine Evolution may be the right choice when the boat already has a Raymarine ecosystem. The choice between EV-200 and EV-400, however, depends on loaded displacement, steering type, and drive — not length alone:

• Installation is simpler (EV-1 condenses compass + IMU in a single housing),
• Native integration with Axiom MFDs is excellent, and most candidate boats are already Raymarine-equipped straight from the yard,
• Auto / Track / Wind modes are perfectly suited to offshore cruising that doesn’t demand extreme tuning finesse,
• Total installed cost is generally 10-15 % lower than the equivalent B&G configuration, because you capitalize on the existing Raymarine ecosystem.

Exception: if the boat has a heavy rudder stock (Garcia, Allures, Boréal, some Ovni), the ram over-sizing must be taken very seriously regardless of ecosystem.

Amateur / club regatta (IRC or ORC weekend racing, fast cruising)

B&G NAC-3 gains the edge if you plan to seriously exploit wind/heading/VMG functions. The tuning granularity is better, dialogue with a potential H5000 is native, and Expedition integration is standard. For this type of program, the autopilot isn’t just "holding course": it becomes a third crew member that steers better than you upwind, and you need to be able to give it the right parameters.

This also applies if you plan to keep the boat beyond a racing cycle and want a scalable platform.

Semi-pro long-range cruising (round-the-world, charter program, bareboat)

It depends. Honestly.

• If operational reliability is paramount and the boat will pass through areas where Raymarine dealers outnumber B&G dealers (Pacific, Caribbean), Raymarine is more defensible. Spare parts matter as much as performance.
• If the program includes sporty passages like Cape Verde / Brazil / direct route, and a skipper who knows how to tune an autopilot, B&G retains a technical edge in difficult conditions.
• If the boat is destined for large-scale charter (e.g. catamaran), Raymarine dominates for operational reasons: rotating crews, international support, ease of use.

In all cases, a long-range cruising program deserves a proper engineering pre-study: this is exactly the situation where one hour of pre-study avoids several thousand euros of post-installation fixes. See our technical studies and 3D design service.

Common field errors observed by Skysat

Here are the real traps we fix regularly, either in refits or in warranty claims from the first installation.

1. Undersized ram

Top trap, by far the most frequent. A 45 ft cruising sailboat with a Type 1 ram when it should be Type 2: it works in flat calm, but falls apart in beam seas. The computer’s algorithm can’t fix this; the motor doesn’t have the power to respond quickly to the command.

Real field case (client anonymized): Sun Odyssey 45.2, coastal program then decision to do an offshore passage. The autopilot had been sized for calm coastal use. First gale in the Bay of Biscay: autopilot in safety mode after a few minutes, helmsman at the wheel for 36 hours. Refitted with an upper-class ram and redundant rudder sensor. Autopilot perfectly operational on the next offshore passage, with no safety triggers.

Skysat rule: we always size for the most demanding predictable program, not for average use. The extra cost of the upper-class ram is marginal compared to the total installed cost. The safety delta is immeasurable.

2. Confusing electromechanical vs hydraulic ram

On a 40-50 ft sailboat, the choice between a linear electric drive and a hydraulic one is essentially based on:

• usage frequency (charter / liveaboard leans toward hydraulic for durability),
• space available (linear electric is more compact, hydraulic requires pump + circuit),
• acceptable noise in the aft cabin (hydraulic is quieter at steady state).

Real field case (client anonymized): Hanse 458 fitted with a linear electric drive because that’s what the yard delivered. Program shifted to long-range cruising with three rotating crew. After 18 months, clunks and significant mechanical play. Converted to hydraulic: quiet restored, nominal durability. The linear electric would have been fine for weekend use.

3. Incorrect gain settings

The autopilot doesn’t work, you call the installer, and the issue isn’t hardware: it’s the gains that are at fault. On B&G NAC-3 in particular, the richness of exposed parameters can lead to an autopilot that’s "over-reacting" in rough seas if profiles have never been fine-tuned beyond the initial setup.

Real field case (client anonymized): Bavaria 46, crew complaining that « the autopilot makes me sick » at 25 knots. Diagnosis: default « racing » gain profile applied even though the program is comfortable cruising. Reset to a cruising profile, adjusted amplitude / counter-rudder. No more complaints.

Skysat advice: commissioning must include a sea trial in representative conditions, not just a dockside setup. This is included in our standard services.

4. Insufficient power supply

A 40-50 ft sailboat autopilot, when loaded, draws several amps peak at the ram. An undersized power supply (cable cross-section too small, service battery aging, fuse at limit) causes voltage drops on load peaks, and the computer goes into degraded mode without a clear message. You suspect the autopilot; the culprit is the electrical distribution.

Advice: dedicated cable cross-section, matched fuse, and a healthy battery bank are non-negotiable prerequisites. This is also a natural opportunity to review the boat’s overall energy balance (alternator, MPPT, hydrogenerator).

Additional article: Sizing a lithium battery bank for a sailboat — the workshop method

How to choose: the Skysat checklist

Before ordering, these 8 questions clarify 90 % of the choice.

1. What program is dominant? Coastal, offshore, charter, racing?
2. Length and displacement of the boat (not just the foot: a Pogo 12.50 and a Garcia 12 don’t demand the same ram)?
3. Type of steering: wheel (almost always on 40-50 ft), tiller (rare)?
4. What existing electronics ecosystem on board? If Raymarine is already wired everywhere, switching to B&G is rarely justified.
5. Is there already an H5000 or equivalent system? If yes, NAC-3 becomes logical.
6. Which routing software planned (Adrena, Expedition, Squid, none)?
7. Total installed budget, distinguishing between hardware / ram / labor / sea trial commissioning?
8. Refit or new installation? On refit, the hidden cost is running new cables in the existing setup. Hardware isn’t everything.

From these answers, we produce a priced recommendation in 3-5 days in our engineering department. See our technical studies and our installations.

Conclusion: a good autopilot is first and foremost a good engineering file

On 40-50 ft sailboats, B&G and Raymarine are equivalent when correctly sized. What distinguishes an installation that lasts ten years from one that ends up in warranty claims is rarely the brand: it’s the quality of the engineering file, the correct sizing of the ram, coherence with the onboard ecosystem, and real sea trial commissioning.

If you’re preparing a specific project — refit or new build — we offer a custom pre-study that covers exactly this scope. You describe the boat and the program, we send back an argued recommendation (hardware, ram, integration, total installed budget). No copied-and-pasted quotes: a real file, signed.

Request an autopilot pre-study — Skysat engineering department, Carnac.

Skysat distributes B&G, Raymarine, Simrad, Lowrance, Garmin, Furuno, among others. This article reflects our viewpoint as an installer and engineering department: it is neither sponsored nor oriented to push one brand over another.

Further reading

• Sailboat autopilot comparison tool — 4 systems side by side, calculator and indicative HT prices.
• Hydraulic vs electromechanical ram: which choice for your sailboat
• Maintaining your autopilot ram: expert recommendations
• NKE Gyropilot vs B&G H5000 — high-performance racing autopilot
• NMEA 2000 on sailboats — architecture, backbone, terminators
• All autopilots in stock

About the author

Pol Conin, Digital Manager at Skysat. Software engineer and tech entrepreneur, Pol joined the adventure to bring Skysat into the digital age. Goal: transition from a classic engineering department to a global technology platform. See his author page for the full list of articles signed.

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