On any saltwater boat, once the engine is sorted, the most important systems on board are your navigation and sonar. A quality MFD does far more than simply tell you where you are. It allows you to understand bottom contour, locate subtle structure, track water temperature changes and, ultimately, use sonar to find fish. When those systems are slow, cluttered or unreliable, they cost you time and confidence. When they work properly, they quietly become one of the most trusted tools on the boat.
The Simrad NSS4 is the latest evolution of a platform that has proven itself offshore for many years. After moving across from the Evo3S, it’s immediately clear this is not a minor update. It’s faster, more refined and significantly more customisable, while still retaining the Simrad DNA that saltwater anglers have relied on for a long time.
Simrad experience
I’ve been running Simrad units since 2016, starting with a GO7 before progressing to the Evo3 and then the Evo3S across multiple boats. Over that time those units have been responsible for me catching a lot of fish, but more importantly they have been completely reliable. In all those years I never had a single return, glitch or unexplained issue. That kind of long-term dependability builds trust, and it’s why I’ve been comfortable recommending Simrad to other anglers for years.
It’s also important to explain how I use these units. I’ve never run an NSS series unit with a 3-in-1 or any form of transom-mounted transducer. My experience has always been with high-end through-hull transducers, specifically the B175HW and SS175HW, and used exclusively for bay and offshore saltwater fishing. Downscan and Sidescan simply haven’t been a priority for the way I fish offshore.
On my estuary boat, a Stacer 589 Crossfire, I run Lowrance units, which is Simrad’s sister brand. That boat is set up for inshore and estuary work where different tools make sense. While both brands share technology and DNA, there is a clear distinction in how they’re positioned. Simrad is firmly focused on saltwater and offshore applications, while Lowrance is aimed more toward inshore, estuary and inland fishing. That distinction makes sense in an Australian context and allows each brand to excel in the environments they are best suited to.
Unit speed and operating power
The most noticeable change when stepping up to the NSS4 is speed. Simrad have moved to a completely redesigned operating system paired with a powerful processor, and the difference is immediate. The Evo3S was already a capable and responsive unit, but the NSS4 feels like a generational leap rather than an incremental improvement.
My current setup consists of twin NSS4 16-inch units, with a third 12-inch unit about to be added. The system is running Simrad Autopilot, Simrad Halo20 radar, Simrad VHF, NMEA data from the engine and stereo, and the Simrad S3100H sonar module. Despite the amount of data being processed, the system never feels loaded. Page changes are instant, sonar adjustments happen in real time and there is no lag when switching between functions or views.
This kind of responsiveness matters offshore, when conditions are rough or you’re trying to make quick decisions. Everything feels deliberate and confident, and that carries through into every part of the user experience.
Charting and navigation
Charting performance is one of the standout strengths of the NSS4. I run C-MAP X-Gen REVEAL charts, and the level of detail they provide is excellent. Shaded relief makes subtle bottom changes far easier to interpret, especially in large bays where structure can be minimal, while satellite imagery adds valuable context when navigating close to land or fishing unfamiliar areas.
What really stands out is how effortlessly the NSS4 handles these layers. I can zoom out from a full Australian overview straight down to a specific fishing mark without any redraw delay. Even with relief shading and satellite imagery active, everything remains smooth and fluid.
Radar overlay on the chart page works extremely well. I don’t run it all the time, but when I turn it on it comes on quickly and integrates cleanly with the chart. At night it’s invaluable for seeing where other boats are positioned, whether they’re moving or already set up on a spot you might be planning to fish. It adds situational awareness without cluttering the screen or slowing the system down.
Auto navigation is another genuinely useful feature. Rather than simply drawing a straight line to your destination, the NSS4 calculates a safe and efficient route that avoids shallow water, rocks, bommies and other hazards. Offshore and in large bays this takes a lot of mental load off the skipper, particularly when running in low light or unfamiliar areas. Paired with autopilot, which is precise and dependable, longer runs become easier and less fatiguing.
Sonar performance
The NSS4 arrived just in time for snapper season, which is the ultimate test for any sonar in Port Phillip Bay. Fishing this environment often feels like searching for fish in a huge empty bowl, with very little obvious structure to work from. This is where sonar either earns its place or exposes its limitations.
The Evo3S was always strong in these conditions, but the NSS4 builds on that through improved processing and significantly greater customisation. While the unit includes the usual preset colour palettes, you can now fully customise each palette and save it. I’ve created several palettes specifically for snapper fishing and will build others for different species depending on depth, bottom type and conditions.
One of Simrad’s most powerful sonar tools remains colour erase. This feature allows you to remove weaker returns caused by jellyfish, sediment or light weed while retaining strong returns from solid objects like fish and structure. By erasing the minor colours and increasing gain, you end up with ultra-clear, highly defined readings without clutter.
Paired with the 175HW high-wide transducer, which runs a wide beam angle, fish show up clearly even when they only clip the edge of the sonar cone. On a recent trip I marked three snapper, one clearly larger than the other two. I caught all three fish, weighing 7kg, 4kg and 3kg respectively. That kind of consistency builds confidence. If I see fish on the screen and I’m not catching them, I know the issue is my approach, not the sounder.
S3100 module and heave compensation
The addition of the S3100 sonar module has been a major upgrade, particularly this season. One of its standout features is heave compensation, which keeps fish and bottom readings stable and correctly formed even when conditions are rough.
This season’s weather has been challenging, and I’ve spent plenty of days fishing in genuinely unpleasant conditions. In those situations, traditional sonar can distort readings as the boat pitches and rolls, forcing you to second-guess what you’re seeing. Heave compensation largely removes that doubt. Fish arches and bottom structure remain flat and consistent, even when the sea state is far from ideal.
That reliability means I’m not questioning whether a distorted return is real or simply a result of boat movement, which makes a big difference when sounding in rough water.
Waypoints, customisation and usability
Waypoint management on the NSS4 is fast and intuitive. Adding marks is simple, with a full QWERTY keyboard, a wide range of species icons and colour options, and large, easy-to-read waypoint labels. When you have hundreds of marks in a small area, that clarity makes finding and navigating to the right spot far easier. The search function allows you to quickly locate a specific waypoint and navigate to it without scrolling endlessly through lists.
Customisation is one of the NSS4’s strongest features. The widget sidebar can be tailored on any page to display exactly the data you want to see, and the interface feels familiar to anyone who uses a modern smartphone. Despite the unit’s ability to manage very complex systems, it remains extremely user friendly.
Big-boat capability, small-boat simplicity
While I run the NSS4 on a 6m Edencraft, it’s important to understand that these units are designed to sit at the heart of much larger vessels. They’re capable of handling multiple transducers, complex sonar modules, radar, autopilot, cameras and extensive NMEA networks. That level of capability usually comes with a steep learning curve, but Simrad have done an excellent job of keeping the system approachable.
If you’re not an experienced skipper or captain, you’ll still find the NSS4 easy to use. The operating system is logical, clean and intuitive, and most functions can be accessed quickly without digging through menus. It’s powerful enough for serious offshore systems, yet simple enough that you don’t need to be highly technical to get the most out of it.
Integration and real-world detail
Integration across systems is another area where the NSS4 really stands out, particularly when paired with modern outboards and onboard electronics. I run a Mercury Verado 300, and engine integration is handled through the Mercury app, which many users will already be familiar with. What Simrad have done well is not just display basic engine data, but present it in a way that’s genuinely useful, highly customisable and easy to read at a glance.
Through the Mercury app, you can completely tailor how engine data is displayed on the NSS4. RPM, speed, fuel flow, fuel economy, temperatures, voltage and trim can all be arranged to suit how you operate your boat. You can change data sizes, colours and layouts, allowing you to prioritise the information that matters most to you. Whether you want large, simple readouts for cruising or a more detailed data-rich screen when travelling long distances offshore, it’s easy to set up.
That customisation isn’t limited to the engine alone. The NSS4’s instruments panel allows you to integrate and display data from other connected systems as well. Units such as Simrad Recon trolling motors, Mastervolt power management systems and other NMEA-connected devices can all feed data into the same interface. The result is a centralised, clean and logical dashboard that gives you a complete picture of what’s happening on the boat without needing multiple standalone gauges.
The practical benefits of this integration really show up on the water. A good example is the way the NSS4 integrates with the Mercury binnacle. If you’ve been fishing at night with the unit set to night mode and the brightness turned right down, you can raise the screen brightness directly via the Mercury controls. Being able to adjust screen brightness while driving at night, without leaning forward and touching the display, is a small detail but one that genuinely improves usability and safety.
Rather than feeling like a collection of separate systems bolted together, the NSS4 acts as the hub that ties everything into a single, coherent interface. It’s powerful enough to manage complex setups, yet intuitive enough that you don’t need to be highly technical to take advantage of it. That balance between capability and usability is a big part of what makes the NSS4 such a strong platform for both smaller trailer boats and larger, fully integrated offshore rigs.
Final thoughts
The Simrad NSS4 is not just a faster Evo3S. It’s a meaningful evolution of a proven offshore platform. The speed, sonar clarity, customisation and system integration all contribute to a unit that feels confident and refined on the water.
For anglers who fish bays and offshore and want a system they can trust, whether on a compact trailer boat or a much larger offshore vessel, the NSS4 delivers where it matters most. It’s powerful without being intimidating, highly capable without being complicated, and it continues Simrad’s long-standing reputation as a serious fishing and navigation tool.
Words & Images: Kosta Linardos
