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

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

On a 40-50 foot sailboat, choosing an autopilot is rarely a brand choice. It is 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 are 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 have learned from regularly equipping both families over five years, on about sixty sailboats in this range. The goal is not to crown a winner: it is to give you the decision grid we use in our engineering department. We distribute both brands. We state this honestly. This does not prevent us from having clear preferences depending on the case.

Understanding autopilot architecture (the 3 minimum components)

Before comparing two ecosystems, you need to understand that autopilot is a catch-all term. An autopilot is not a single box. It consists of at least three distinct components that communicate.

1. The computer (CPU)

This is the brain. It receives input from the helmsman (heading, wind angle, course), sensor data (compass, accelerometer, speed, wind transducer) and outputs commands to the ram. It is the component that contains the brand-specific algorithm. At B&G, it is the NAC-3 or NAC-2, depending on displacement and rudder class. At Raymarine, it is the Evolution unit (ACU, Autopilot Control Unit), available in several versions depending on ram power: EV-100, EV-200, EV-300, EV-400.

It is also this component that contains — or connects to — the inertial measurement unit (IMU). 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 is 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 reading.

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

3. The ram (drive unit / linear ram)

This is the muscle. It receives orders from the computer and moves the rudder stock (via the quadrant or directly) or the tiller. On 40-50 foot sailboats, you are almost exclusively using a hydraulic ram or electromechanical linear ram 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 an autopilot "zigzagging" in beam seas. And it is a recurring trap: we address this further down.

For more on rams, see our dedicated guide: Bar ram for autopilot: how to choose, install, and maintain. (additional article)

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 a line of ACP units that began at B&G in the 1990s and was refined with each Olympic cycle and Vendée Globe.

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

Raymarine: the pragmatic approach

Raymarine has a different philosophy: an ecosystem aimed at a wider public, easier to implement, better supported internationally, and natively integrated into Axiom MFDs with a renowned touchscreen interface. The Evolution Pro range (with ACU EV-400 typically on 40-50 foot sailboats with a hydraulic ram) is based on a 9-axis sensor (3-axis compass + 3-axis accelerometer + 3-axis gyroscope) integrated into the EV-1 unit, which radically simplifies installation.

This is the ecosystem found on most recent Beneteau, Jeanneau, and Hanse sailboats straight from the yard. This matters: if your 40-50 foot sailboat is a Sun Odyssey 410, an Oceanis 461, or a Hanse 458, you probably already have Raymarine wired. Reconfiguring everything to B&G is not absurd, but it is 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 recommend you validate with the distributor's price list on the day you request a quote — they fluctuate with each price revision.

*Indicative 2026 figures excluding labor, excluding specific wiring, excluding redundant rudder sensor. Price ranges vary according to final configuration and distributor list price in effect.

See also: our autopilots in stock. And for product pages, the B&G / Navico NAC-3 computer and the Raymarine Evolution autopilot (p70Rs + ACU-200, Type 1), sized for a 40-50 foot sailboat.

Quick reading of the table

Three lines deserve comment:

• Compass / IMU: the major difference in approach. B&G separates the autopilot from the compass, allowing the use of a high-end system (Hercules on H5000) while sharing data with the instruments. Raymarine integrates everything into the EV-1, which simplifies installation but ties the compass dedicated to the autopilot.
• Sailing routing: if you use Expedition, the H5000 is the natural partner. If you are using Adrena for amateur racing, both ecosystems work honestly, with a slight advantage for B&G via the 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 is how we guide clients in the pre-study phase.

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

Raymarine Evolution Pro (EV-400) will, in the majority of cases, be the right choice. Not because it is absolutely better, but because:

• Installation is simpler (EV-1 condenses compass + IMU into a single unit),
• Native integration with Axiom MFDs is excellent, and most candidate boats are already equipped with Raymarine straight from the yard,
• Auto / Track / Wind modes are perfectly suited to offshore cruising that does not require extreme fine-tuning,
• 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 oversizing must be taken very seriously regardless of the ecosystem.

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

B&G NAC-3 takes the lead if you plan to seriously exploit wind/heading/VMG functions. The granularity of adjustment is better, the dialogue with a potential H5000 is native, and integration with Expedition is standard. For this type of program, the autopilot is not 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 is also the case if you plan to keep the boat beyond a racing cycle and want an upgradeable platform.

Semi-pro long-range cruising (world tour, charter program, rental)

It depends. Honestly.

• If operational reliability is paramount and the boat will pass through areas where Raymarine dealers are more numerous than B&G dealers (Pacific, Caribbean), Raymarine is more defensible. Spare parts matter as much as performance.
• If the program includes sporty passages such as Cape Verde / Brazil / direct route, and a skipper who knows how to tune an autopilot, B&G retains a technical advantage in difficult conditions.
• If the boat is intended for large-scale charter (e.g., catamaran charter), Raymarine dominates for operational reasons: changing 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 seen on +60 Skysat installations

Here are the real traps we regularly correct, either in refits or in warranty repairs after the first installation.

1. Undersized ram

First trap, by far the most frequent. A 45-foot cruising sailboat with a Type 1 ram when it should have a Type 2: it works fine in flat calm, but cuts out in beam seas. The algorithm in the computer cannot compensate; the motor does not have the power to respond quickly to the command.

Real-world case (anonymized): Sun Odyssey 45.2, coastal program then decision to do a transatlantic. The autopilot had been sized for calm coastal use. First rough seas in the Bay of Biscay: autopilot went into safety mode after a few minutes, helmsman back at the wheel for 36 hours. Refitted with a higher-class ram and redundant rudder sensor. Autopilot worked perfectly on the next transatlantic, with no safety triggers.

Skysat rule: we always size for the most demanding program expected, not the average use. The price difference for the ram alone is around €400-700 (VAT excluded). The safety difference is immeasurable.

2. Confusion between electromechanical and hydraulic rams

On a 40-50 foot sailboat, the choice between a linear electric ram and a hydraulic ram is primarily based on:

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

Real-world case: Hanse 458 equipped with a linear electric ram because that is what the yard delivered. Program shifted to long-range cruising with three rotating crew. After 18 months, clunking and mechanical play appeared. Converted to hydraulic: noise and durability restored. The linear electric ram would have been perfect for weekend use.

3. Incorrect gain settings

The autopilot does not work, so the installer is called, and the issue is not hardware: it is the gains that are set to default. On B&G NAC-3 in particular, the wealth of exposed parameters can lead to an autopilot that "overreacts" in rough seas if profiles have never been fine-tuned beyond the initial setup.

Real-world case: Bavaria 46, crew complaining that "the autopilot makes me sick" in 25 knots of breeze. Diagnosis: default "racing" gain profile applied while the program is comfortable cruising. Reset to a cruising profile, adjusted amplitude/counter-helm. 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

An autopilot on a 40-50 foot sailboat, under load, draws several peak amps to the ram. An undersized power supply (cable cross-section too small, service battery degraded, 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 with appropriate cross-section, properly sized 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).

Upcoming additional article: How to size your lithium battery bank for long-range cruising (article 10 of our series)

How to choose: the Skysat checklist

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

1. What is the dominant program? Coastal, offshore, charter, racing?
2. Length and displacement of the boat (not just the LOA: a Pogo 12.50 and a Garcia 12 do not require the same ram)?
3. Type of rudder: wheel (almost always on 40-50 foot sailboats), tiller (exceptional)?
4. What existing electronics ecosystem is 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, the NAC-3 becomes logical.
6. What routing software is envisaged (Adrena, Expedition, Squid, none)?
7. What is the total installed budget, distinguishing between hardware / ram / labor / sea trial commissioning?
8. Refit or new installation? On refits, the hidden cost is pulling new cables through existing runs. Hardware is not everything.

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

FAQ

Can you integrate a B&G autopilot into a Raymarine network, and vice versa?

Yes for basic data, via NMEA 2000 — the shared standard bus. GPS position, speed, wind, heading: this data flows between ecosystems without difficulty. However, the native user interface remains that of the manufacturer: an Axiom MFD does not engage a NAC-3 with the same ergonomics as a Zeus, and a p70s control head does not natively pilot a NAC-3. For 90% of cases, it is better to stay consistent within one ecosystem for the autopilot chain.

Which ram to choose for a 45-foot aluminum sailboat?

On a 45-foot aluminum sailboat such as Allures, Garcia, Boréal, or some Ovni, displacement and rudder stock require at least a Type 2 ram, preferably hydraulic for durability. The exact calculation is based on maximum torque at the rudder stock, not just length. This is a systematic engineering point.

Is the H5000 system compatible with the NAC-3?

Yes, it is even the reference combination on the B&G side. The H5000 (CPU and Hercules) communicates with the NAC-3 over the FastNet/N2K bus and provides the autopilot computer with wind and speed data of higher quality than an entry-level system. This is the structural argument for a performance-oriented program.

Is the NAC-3 compatible with existing Raymarine rams?

Yes, via an adapter interface and a re-check of sizing. We do this on some refits where the client wants to switch back to B&G but preserve the recent hydraulic system. This is not a "plug and play" case: we always document compatibility on a case-by-case basis.

What is the difference between EV-200, EV-300, and EV-400 at Raymarine?

These references correspond to ram power classes: EV-200 for mid-sized boats (up to ~13 meters in practice), EV-300 and EV-400 for larger segments with Type 2 and Type 3 hydraulic rams. On 40-50 foot sailboats, the EV-400 is the dominant reference with a hydraulic ram. The computer changes with the class (ACU-200 / ACU-300 / ACU-400).

Can you engage the autopilot as soon as the engine is running, or do you need to be at steady speed?

Technically yes, but at very low speed the autopilot struggles to correct because there is little rudder effect. Above ~2 knots forward, engagement is reliable. In harbor maneuvers, we always disengage.

What is the cost of a complete installation on a 45-foot sailboat in a refit?

Ballpark figure, excluding specific complications: between €8,000 and €14,000 (VAT included) for a complete kit (computer + control head + new ram + rudder sensor + wiring + labor + sea trial commissioning). The range widens depending on ram configuration, cable runs, and integration with the rest of the electronics. A personalized quote is essential. See our installations for priced examples.

How long does an autopilot installation take in a refit?

Three to five days in the workshop on average for an autopilot installation alone, including half a day to a full day of sea trial commissioning. A refit that also includes switching to N2K, changing instruments, or a new MFD can take up to two weeks.

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

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

If you are preparing a specific project — refit or new build — we offer a customized pre-study that covers exactly this scope. You describe the boat and the program, and we return a reasoned recommendation (hardware, ram, integration, total installed budget). No copy-pasted quotes: a real, signed file.

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

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

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: to transition from a traditional engineering department to a global technology platform. See his author page for the full list of articles signed by him.

Wikidata: Q139565078