7 min read

We all love our B&G MFD. It’s probably one of those assets that simply cannot be absent from a boat—like the rudder, the anchor, or the sails themselves. Together with GPS, multifunction displays have genuinely improved navigation to a level of comfort that is unprecedented. But what is their ultimate purpose? And more importantly, are we actually using them to their full potential?

More Than Just a Chart Plotter

Let’s be honest: having charts and GPS can be done on any tablet or phone these days. Wind data are ultimately displayed more effectively on dedicated instruments like the B&G Triton. So what exactly makes the MFD so essential?

The real value of a multifunction display comes from another subsystem lurking beneath—called NMEA 2000. This network is effectively gathering all your boat’s information in one place. And importantly, it also allows you to set and control many other subsystems from a single interface.

What makes an MFD genuinely valuable is the ability to collect ALL this data in one user interface—allowing you to shift focus from AIS to radar, from depth to current calculation, from engine parameters to battery status, all without leaving the helm.

The “Display” in Multifunction Display

Here’s an interesting observation: most MFDs do very little in terms of control actions on other subsystems. The notable exception is radar, where the MFD serves as the primary interface. But for most other systems, the MFD’s role is exactly what the name suggests—it displays data to the crew.

And this is precisely where the weak point emerges.

RTFM: The Eternal Struggle

MFD manuals run to hundreds of pages. Hundreds. And let’s be brutally honest—they’re usually unread. RTFM (Read The F***ing Manual) is an acronym we’re often reminded of by service companies when we call with a problem.

But here’s the reality:

• The manual for a modern B&G Zeus or Vulcan runs 200+ pages
• Features are nested in menus within menus within menus
• Settings change with firmware updates
• Integration with other devices adds layers of complexity
• Different crew members have different levels of technical comfort

The weak element of the chain is, once again, our human capacity to set up, read, and interpret the enormous amount of data that flows through these devices.

The Fatigue Factor

And then there’s fatigue—the silent killer of competence at sea.

What we understand in winter, sitting on the sofa at home, is absolutely not what we understand in the middle of an emergency at 3 AM.

That complex waypoint sequence you programmed so carefully? Good luck modifying it with cold, wet hands while the boat is heeling 25 degrees and the spray is hitting the display. That radar overlay feature you practiced in the marina? Try interpreting it when you haven’t slept in 18 hours and there are three targets that all look threatening.

Our cognitive capacity degrades dramatically under stress and fatigue. The MFD doesn’t care—it presents the same complex interface whether you’re fresh and alert or running on fumes and adrenaline.

When It Really Matters: A Personal Story

That experience taught us something important: MFDs are indeed incredibly useful—if you know how to use them. Not just the basic features, but the creative workarounds that can save your boat when conventional solutions fail.

The Hidden Danger: Scale Deception

But MFDs can also be dangerous. Perhaps the most insidious danger is chart scale.

A chart at the wrong scale can hide the reef you definitely want to avoid. That little symbol that looks like a minor depth contour at 1:50,000 scale? At 1:5,000, it’s a rock that will end your voyage.

We’ve seen experienced sailors nearly come to grief because:

• The MFD auto-zoomed to a scale that hid critical detail
• Raster charts didn’t load properly at certain zoom levels
• Vector chart data was incomplete for the area
• The display was set to “declutter” mode that hid important symbols
• Sun glare made the screen unreadable at the critical moment

The Integration Illusion

Modern MFDs promise seamless integration. Everything in one place. One screen to rule them all.

The reality is more nuanced:

The MFD shows you the data. You have to correlate it, interpret it, and act on it. At 3 AM. In 30 knots. After 12 hours of sailing.

The “Head-Down” Problem

Here’s another fundamental flaw in the MFD paradigm: they’re only useful when actively watched.

MFDs completely lack the basic functionality of alerting somebody who isn’t sitting directly in front of them. And here’s the reality of recreational sailing: unlike an IFR pilot who must fly “head-down” monitoring instruments, we don’t spend our time at sea staring at displays.

We’re enjoying sailing. Looking at the horizon. Trimming sails. Having a conversation. Making lunch. Or—quite often—sitting in the toilet of the forward cabin.

And that remote “beep-beep” you hear faintly from the cockpit? The one that sounds exactly like every other beep-beep the system makes? It could be telling you:

• The autopilot has disconnected
• The depth is below your minimum threshold
• An AIS target is on collision course
• The anchor alarm has triggered
• The waypoint arrival circle has been reached
• …or that the fish finder has spotted something interesting

If you hear the beep at all from the forward cabin. Over the sound of the engine. While the door is closed. And the hull is creaking.

MFDs are fundamentally designed for active monitoring—they expect a human crew member to be watching them at all times, ready to notice changes, interpret data, and respond to alerts. But that’s not how we actually sail.

We sail heads-up, enjoying the experience, occasionally glancing at the instruments. The MFD sits there, full of critical information, waiting for someone to look at it. And when it really needs our attention, it makes the same sound it makes for everything else—and hopes we’re listening.

The Way Forward

• They’re only as good as our knowledge of them—invest time in actually learning your system
• They don’t think for us—they display data, we make decisions
• They’re designed for good conditions—practice using them when you’re tired and stressed
• They can deceive as easily as inform—always verify critical navigation with multiple sources
• The crew needs training too—not just the captain

The multifunction display has earned its place at the heart of modern navigation. But perhaps it’s time we asked: what would it look like if these systems were designed not just to display data, but to actively help tired, stressed sailors make better decisions?