Building custom marine HMI systems for modern boats

A boat’s helm used to be a massive steering wheel, and not much more. But today, it resembles a software product a lot – and there are reasons behind this. 

In the United States alone, recreational marine spending hit $54 billion in 2025, according to the National Marine Manufacturers Association. The market recorded 220,397 new recreational boat sales, while aftermarket accessories brought in another $12.1 billion. 

Those numbers show us a bigger picture – a market where the onboard experience has become part of the product. Buyers expect the helm to feel as considered as the rest of the boat. OEMs, meanwhile, need the software underneath it to hold up against real marine challenges.

Regulation is moving towards more software-defined vessels, too. In May 2026, the International Maritime Organization adopted its first global code for Maritime Autonomous Surface Ships. It covers navigation, connectivity, remote operations, and cybersecurity – and it keeps human oversight as a central principle.

So, if you are building a custom marine HMI, it takes much more than putting a modern UI on an embedded display. Your engineering team has to wire the interface to real vessel data, keep interaction responsive under load, test behaviour against hardware, then maintain the software after launch.

We take a closer look at what goes into this process – from marine protocols and HMI architecture to hardware-in-the-loop testing, latency control, and OTA updates.

What is a marine HMI?

A marine HMI, short for human-machine interface, is the onboard software layer used to monitor and control a vessel’s systems. It talks to hardware over marine communication protocols to pull in system data. Then it presents that data to operators in a way that supports fast, reliable decisions at the helm.

Key shifts in the marine software industry today

Currently, the marine industry is undergoing one of the biggest changes in decades – and a lot of it is happening on screens, not in hulls. Software no longer plays a supporting role but now sits at the centre of how modern boats are designed and operated. There are two major forces behind this.

From analogue gauges and isolated MFDs to software-defined vessels

For most of recreational boating’s history, the helm was a patchwork, where analogue gauges reported engine data, and a standalone chartplotter handled navigation. Meanwhile, the radio, autopilot, and sonar each had their own screens and controls. Even when multifunction displays showed up, they usually sat beside the boat’s other systems rather than at the centre of them. In the end, the skipper had to piece the picture together from a dozen sources.

That model is giving way to the software-defined vessel. Propulsion, navigation, power management, lighting, climate, and entertainment now run over common networks and show up on unified displays. Functions that used to be fixed in hardware now get delivered and refined through software, which means a boat can pick up new features and bug fixes long after it leaves the factory.

A good example of this is Volvo Penta’s Glass Cockpit. The system pulls navigation, engine data, warnings, and other boat functions into one touchscreen interface, with configurable displays from 7 to 24 inches. It also connects to Volvo Penta’s Electronic Vessel Control system, which makes the HMI part of the vessel’s control architecture instead of a separate information screen.

There is also Mercury Marine’s VesselView, a family of multifunction displays that swaps traditional analogue engine gauges for a single digital interface for boats with SmartCraft-compatible Mercury engines. It shows more than 30 engine parameters – from fuel level and range to oil pressure and battery voltage – and gives users plain-language fault messages. VesselView can also pull navigation and sonar, as well as digital switching, onto the same screen. 

Rising user expectations driven by EVs

Next come electric boats that are advancing the industry further. Boaters already know what a modern EV cockpit feels like. Based on this, they expect important information to sit in one place and vehicle status to be easy to read. Thus, the interface should keep up with what the vehicle is doing.

Another important aspect that influences these growing expectations is electric propulsion. On an electric boat, range anxiety is real and energy data matters the whole time, and the marine HMI should reflect that with an easy-to-understand design. 

We can see this trend in Frauscher x Porsche 850 Fantom Air. This electric dayboat comes from Austrian boatbuilder Frauscher, built in collaboration with Porsche, and the automotive influence shows. The electric drivetrain is borrowed from Porsche’s EV programme. In addition, the helm carries Porsche’s design language, with a digital cockpit that will look familiar to anyone who’s driven one of the brand’s electric cars.

There is the X Shore Eelex 8000 electric boat. Forbes describes it as the ‘Tesla of the seas’, and it is aimed at buyers who expect their boat to feel as connected as their car. The Swedish builder’s boats have a big central touchscreen, a minimal helm with barely any physical controls, and a companion app for checking battery status and boat data remotely. 

Custom marine HMI vs. off-the-shelf control panels at a glance

Off-the-shelf control panels usually make sense when a boat needs an industry-proven interface with a standard feature set. They cut down initial development work and give the engineering team a known hardware baseline.

However, the trade-off appears when the HMI becomes part of the product experience, like the one we mentioned above. That is when custom marine HMI development starts to pay off.

A custom HMI gives the product team more room to decide how the vessel looks and works long-term, as well as communicates with its systems. It also offers engineering more control over protocol integration and future software releases. 

	Custom marine HMI	Off-the-shelf control panel
Brand differentiation	Can carry the boat’s visual language and interaction model. The HMI becomes part of the vessel’s identity.	Usually follows the manufacturer’s design system. Different boats feel similar from the helm.
Protocol flexibility	Can adapt to the vessel’s architecture – CAN, NMEA 2000, Ethernet-based protocols, proprietary interfaces, and legacy equipment.	Strong on NMEA 2000 and the vendor’s own ecosystem. Other protocols often require gateways or third-party integration.
UX customisation	Teams can design navigation, alarms, dashboards, touch interactions, and screen layouts around the vessel and its users.	UX follows the capabilities and interaction patterns provided by the panel vendor.
Long-term upgradability	Over the product lifecycle, the software architecture can support new functions and connected services, as well as OTA updates and hardware changes.	Future changes depend partly on the vendor’s roadmap and the panel’s hardware. A new feature may mean a new panel or extra equipment.

Essential UI/UX ergonomic constraints at sea

Marine interfaces deal with things most commercial screens never will. To give you an idea: a captain might be reading a display in the blinding sun. In other cases, they can be working the controls while the boat is rolling – or handling an alarm while keeping an eye on the water and three other instruments at once.

Sunlight readability and auto-switching high-contrast modes

In a workshop, a display may look excellent, but it can turn unreadable on an open bridge. Direct sunlight, reflections off the water, shifting ambient light – all these factors wash out UI elements that seem perfectly legible during marine HMI development.

Consequently, marine HMIs need displays with high luminance, often 1,000+ nits, paired with optical anti-glare treatment. The UI has to account for the environment too. A daylight interface can lean on stronger contrast and brighter elements, while the night mode should cut glare and preserve the operator’s dark adaptation.

Automatic mode switching takes another manual task off the bridge crew. The system can pick the right visual mode using ambient-light sensors, time of day, or operating conditions.

Typography matters just as much. Small labels and low-contrast secondary text become liabilities when an operator has a split second to read a screen.

For more on the principles behind readable marine instrumentation, see our guide to digital marine gauge design.

Touch targets and tactile feedback

A tablet touchscreen assumes steady hands and predictable contact – but a boat gives you neither. Throughout a journey, a skipper’s hands move with the hull, and a steep chop can easily cause a missed tap. 

To avoid this, Google’s Material Design 3 guidelines put the minimum touch target at 48×48 dp. Additionally, Google’s Android accessibility guidance translates that rule into roughly 9 mm on any screen and at least 8 dp between neighbours. For a marine HMI, one might recommend treating those numbers as the absolute floor and sizing primary controls well above them. 

There is another point for consideration that is wet fingers or gloves. They add their own margin of error, and the touch controller needs a firmware profile that rejects water droplets – but still registers a gloved fingertip.

Gestures carry their own risk. On a rolling deck, a wave can throw the captain’s hand across the glass and trigger a swipe nobody meant to make. A motion-aware HMI handles this. The sequence works in the following way: when onboard sensors register strong motion, it blocks swipes and pinch-zooms – and only keeps taps on large buttons live. 

Even so, a touchscreen cannot do everything. In rough seas, captains hold on with one hand and work with the other. For these cases, a physical rotary dial often becomes the most dependable control on the console. Every major MFD brand sells one for exactly that reason. To make sure the dial works well, each screen needs a logical focus order and a visible highlight on the selected control.

Safety-critical alarm hierarchy and cognitive load management

Software-defined vessels now route engine data and cabin comfort controls through the same display stack. Occasionally, this may result in alarm floods. And if several of the alarms carry the same visual weight at once, the captain may have a hard time prioritising the right one.

The answer here lies in a strict hierarchy built into the architecture itself, well below the visual layer. 

1. Top-tier alarms cover the events that can sink the boat or destroy the engine. This may be rising bilge water, coolant temperature past its limit, a depth reading below the safety threshold, and others.
2. Mid-tier warnings – low fuel, for example – sit in a persistent status bar without a takeover. 
3. Everything else – e.g., system events or non-urgent tank or power notices – goes to a log the crew can review later.

Two more rules help prevent alarm floods. First, suppress the knock-on alarms. When a generator trips, the captain needs one root-cause message, not a dozen low-voltage alerts from downstream systems. Second, escalate anything ignored, so an unacknowledged warning climbs to alarm status after a set timeout.

The IMO’s Bridge Alert Management framework adds the ranking. It sorts alerts into four categories, from emergency alarms down to cautions. This way, comfort systems and safety systems share a platform, but they never compete for the operator’s attention.

Commercial shipping already has a solid reference point. NACOS Platinum, an integrated bridge system by NACOS Marine, combines navigation and automation in one marine HMI. Its scope runs from propulsion control all the way to HVAC. But alert-wise, the platform applies the same logic across every subsystem. 

Core system technologies

Interfacing with marine hardware protocols

Equipment on a boat is rarely built to speak a common language. Usually, navigation devices rely on NMEA 2000, while engines use J1939. Then, generators or batteries add Modbus to this mix, and a newer standard – NMEA OneNet – carries heavier data such as radar video over ordinary network cables.

What would be the best practice here is to build a separate connector for each protocol to translate incoming messages into one common format. This way, the display reads a consistent stream of data no matter where it came from. 

Yet, translation solves half the problem, since raw data also tends to be messy. Two GPS units may disagree, or maybe a depth sensor can jump wildly in rough water. Your software should check every reading before it reaches the screen. It should be able to smooth out sudden spikes and switch to a backup GPS if the main one fails. 

Framework selection

Once the data flows reliably, it is time to choose the software foundation. The choice depends on what the product must do. For displays that need to start within seconds and never fail, we might recommend using Qt with embedded Linux. If the roadmap includes apps or online services, you can go with Android instead and plan its long-term updates from the get-go. When a product needs both, you run them side by side. In that setup, Linux handles the critical gauges and Android takes care of everything else.

3D vessel models get the same separation. For docking views, use game engines such as Unity or Unreal but run them as a distinct module – so a glitch in the 3D view never touches the engine gauges.

At Bamboo Apps, we followed this approach in our digital marine gauges project with IQAN, Parker Hannifin’s control platform. 

Multi-display synchronisation and low-latency rendering

While a single screen may be enough for a smaller dayboat, larger vessels rarely have just one. Besides the main helm, there is often a second station on the flybridge, while the crew carries tablets around the deck. Every one of them has to show the same picture at the same moment.

To keep the displays in sync, you can split the data into two streams. Live readings – such as engine speed or depth – travel over MQTT. It is a lightweight protocol designed specifically for unstable connections. A central hub on board sends updates to all screens at once. In case a tablet loses the Wi-Fi connection, it will get the latest readings when it reconnects.

Meanwhile, commands go through gRPC because it confirms that an action has gone through. For example, when the captain silences an alarm on the flybridge, the system knows the command worked and updates every other screen right away. Only one screen holds control at a time, which prevents conflicting commands.

On wired screens, the whole cycle takes less than a tenth of a second, which keeps the gauges smooth and responsive.

The custom marine HMI development process step-by-step

Discovery phase

A marine HMI development project starts with the vessel and its hardware. At this point, your team should define three points:

• what the HMI needs to display
• which vessel systems it will talk to
• what the target hardware can actually handle. 

Engineers also map the relevant CAN and NMEA protocols and agree on display resolution and performance requirements.

Long vessel lifecycles matter here too. If the equipment may stay in service for 25 years, the HMI architecture needs enough flexibility to take on new hardware and software later.

HMI design and interactive prototyping

Next, the work moves towards the conditions people will use the interface in. Here, your team needs to account for many factors, including the ones we already mentioned above. The general rules are as follows:

• The screen has to stay readable in direct sunlight and not turn blinding at night.
• All controls need to work with gloves, wet hands, vibration, and the boat moving underfoot.
• Designers also decide where physical controls – like buttons or rotary knobs – make more sense than touch.

Before the development process starts, designers can test these decisions on interactive prototypes. At this stage, a few rounds of testing can reveal confusing navigation or difficult controls.

Embedded software development and middleware

Once the interface is agreed, engineers connect it to the vessel’s systems. To link the HMI and the data that comes from sensors and other equipment, they install middleware. It handles communication over protocols like CAN and NMEA, as well as decides how the interface behaves when data arrives late or looks wrong.

Engineers also test the HMI on the actual target hardware. Performance can differ a lot from what a prototype shows on a development computer.

Hardware-in-the-loop (HIL) testing and edge-case validation

HIL testing allows engineers to connect the real HMI hardware to a setup that simulates what happens on the vessel. They can cut a CAN signal on purpose or create a voltage drop and watch how the system responds.

The idea is simple – reproduce the hard situations in the lab before they happen at sea. Once engineers find a problem, they turn it into a repeatable test. Future releases then run through the same scenarios without another sea trial.

Deployment and OTA updates

A marine HMI may need updates long after the boat leaves the factory. So, the deployment strategy has to account for different hardware versions, interrupted updates, and recovery when something goes wrong.

OTA updates cut down on the need to bring vessels back for every software change. They also give OEMs a practical way to maintain the HMI across its long service life.

For a product expected to run for decades, the goal is to build an HMI that keeps working, and keeps evolving, alongside the vessel.

Essential features of next-gen marine HMIs

A modern marine HMI connects vessel systems with several user touchpoints. The best, well-thought-out systems adapt to who is using them: a captain at the helm, an owner relaxing below deck, or a technician with a laptop on the dock.

Role-based dynamic profiles

A captain and an owner need different things. Captain profiles can prioritise the following:

• navigation
• propulsion data
• alarms.

Owner profiles can focus on:

• battery status
• comfort systems
• vessel condition.

Role-based access can also control which functions each user can reach. Keep profile logic separate from the core vessel data, so new roles can be added without the need to rebuild the app.

3D digital twins

You can create a 3D vessel model to make complex system information easier to comprehend. For this feature, your team can employ Unreal Engine or Unity, as they can render the hull, decks, propulsion systems, or other equipment – with alerts shown right on the affected part of the vessel.

The same model can support configuration, onboard status views, and service diagnostics. On embedded systems, though, teams need to define rendering targets and hardware limits early. A visually impressive interface still has to hit frame-rate and response-time targets on the hardware it runs on.

Companion app integration

The helm should not be the only place an owner can interact with the boat. A companion app can offer several selected functions, like remote battery status or geofencing alerts.

A useful benchmark for this comes from Mercury Marine’s VesselView Mobile. Boat owners can pull SmartCraft engine data, battery voltage, fault alerts, and maintenance information from a phone. CZone is another reference for remote vessel monitoring and control.

Predictive maintenance

Last, but definitely not least, comes predictive maintenance. Engine hours, temperatures, battery behaviour, pressure readings, and fault history – all these give a marine HMI something to work with.

Good predictive maintenance also depends on how the system reports what it finds. A minor anomaly may belong in the service history, but a developing problem might warrant a mobile notification. Safety-critical conditions need immediate, prominent treatment.

How to choose a marine HMI development company to partner with

Marine HMI development is way more than UI design. Your partner should not only understand the embedded systems underneath the interface, but also know how people use them at sea.

When you evaluate a supplier, ask the following questions:

1. Can they work with marine protocols? Look for experience with CAN, NMEA 2000, proprietary protocols, and hardware APIs.
2. How do they test? Ask about emulators, hardware-in-the-loop testing, and validation on representative hardware before sea trials.
3. How do they measure performance? Response time, communication latency, startup behaviour, frame rates, and resource limits should all have defined targets.
4. How do they handle OTA updates? Version control, security, recovery mechanisms, and failed-update scenarios need thought from the start.
5. Can they connect UX decisions with embedded limitations? A marine HMI partner should understand both what feels intuitive and what the hardware can support.

Bamboo Apps brings HMI experience from the automotive industry, including digital cockpits, instrument clusters, and infotainment systems. Our engineers work across Qt, Kanzi, C/C++, C#, Linux, QNX, and Android Automotive OS, with emulator-based testing.

Marine and automotive systems have different protocols and operating environments, but the engineering challenge overlaps – turning complex hardware and software into an interface people can operate confidently.

Key takeaways

1. The helm has evolved into a software product. Today’s buyers expect the onboard experience to feel as considered as the rest of the boat – and OEMs need software that performs reliably under marine conditions. 
2. Custom HMIs pay off when the interface is part of the product. Off-the-shelf panels are a solid solution for standard feature sets. Meanwhile, custom development gives you more control over brand identity and UX, as well as protocol integration and long-term upgradability.
3. Design for the sea conditions. What this means: 1,000+ nit displays with anti-glare treatment, automatic day/night modes, large touch targets, glove and wet-finger handling, motion-aware gesture blocking, and physical rotary dials for rough water.
4. Build a solid alarm hierarchy into the architecture. You should separate critical alarms, persistent warnings, and logged events. 
5. Normalise and validate data before it reaches the screen. Use a separate connector for each protocol that translates into one common format. 
6. Keep multi-display setups in sync with the right transport. Live readings travel over MQTT, commands go over gRPC for confirmed delivery – and one screen holds control at a time. 
7. Test rigorously and plan for a 25-year lifecycle. Hardware-in-the-loop testing reproduces failures in the lab. OTA updates need to handle hardware variants and recovery. Features like role-based profiles, 3D digital twins, companion apps, and predictive maintenance should sit on an architecture that can evolve.