Maretron N2KView on Dirona

Click image for a larger view

When we go to sea in Dirona there are usually only two people on the boat. That means automation and reliability are super important to us, and we want early warning of problems or unusual conditions. Maretron N2kView is a good-value display system that has worked very well for us and allowed us to incrementally expand what we monitor over time. This system monitors the NMEA 2000 communications bus to give us visibility into almost every instrument in the entire boat, including navigation equipment, weather instruments, main engine, wing engine, generator, depth sounders, inverters, chargers and pumps.

Maretron N2KView is an unusually flexible and well-engineered user interface. Our inclination is to write apps ourselves or use open-source software. But it’s amazing what you can do with N2KView, nothing comes close to it on price, and it would be hard to duplicate the clarity and information density using open-source software.

We’ve designed several displays in N2KView. At the top of this post is the display we normally use when underway (click any image for a larger view). The displays can be configured almost any way desired. Of the three things that we focus on, the first is that we want it to be easy to use even when tired or managing difficult weather. It looks complicated, but in fact the first-level read is just scanning for green lights at each gauge and checking there are no yellow, orange, or red indicator lights. As long as we’re seeing nothing but green lights we know the boat is in good shape and everything’s functioning properly. It’s an easy quick check that we can perform quickly and frequently even when tired.

If something goes wrong we want to know immediately and have more information at our fingertips because we don’t particularly want to wake the other person up but we do want to take quick action. If an indicator light goes to warning, it’ll get noticed quickly and the detailed data to more fully understand the problem is immediately available in a gauge, graph, or numeric display. That’s the second level of protection that we’ve got using this system. For example, the display below shows two potential issues that are obvious with a quick scan: 1) the engine temperature is out of normal range 2) the house battery amp draw is negative. The engine is running cold (top, 2nd from left) because we just started it. That small red light should go to first to yellow and then to green as the engine warms up.

Click image for a larger view

A second potential issue in the above display is that the house battery draw (middle of third row) is showing red, indicating we are drawing the batteries down. This would be a problem if it continues, so we can then dig deeper into that by looking at the historical display below to see if it’s been doing that for a while or if it’s just a spike.

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The screen below shows two more examples of automation and simplification. The red light near the bottom left of the display indicates that the generator is running. We started all three engines to produce the screen shots for this blog, but in normal circumstances the generator should never be running while the main engine is running. The combination of our main engine able to produce 9kw of power and the 240V inverterter being able to run and of the equipment on the boat means we never run the generator when under way. We do use the dryer, the air conditioning, and the oven when underway but don’t need to run the generator (see A More Flexible Power System for Dirona).  Consequently, we display a red indicator to notify us if the generator is on when underway (it’s quiet, so we might not notice it running).

Another potential issue is that the wing is running (yellow light near bottom right). This is not actually an unexpected condition. The wing is used to power our hydraulic thrusters and anchor winch so it’s usually on twice on every trip. But we don’t want to accidentally leave the wing running, so we display a yellow light to help us avoid leaving it running when not needed.

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One thing we’ve found it that consistency across the displays is important for ease of comprehension and locating data. So we designed an indicator “ribbon” where the bottom two rows are identical across all the displays, including the CHK indicator. The same group of indicator lights is displayed in the ribbon. The general rule for indicator lights is they are black if the devices is not currently in use, green if in use and operating correctly, and yellow, orange, or red if on and there is some problem. The indicator lights are the same on every display screen so we can get use to the layout and it never changes. From the other side of the room, I can see that the propane was left on or the hot water heater is below 115F.

We also have a variety of conditions we want to flag that either don’t have a specific gauge or indicator light or we want to make them more noticeable when they occur. For these cases, we have the large check light in the bottom left hand corner of all display screens. This indicator is black for “no issue,” yellow for warning, and red for a problem needing more immediate attention. In the display below, none of the gauge indicators are red, but the red CHK light indicates a serious issue that we need to address right away. We’ll look at a separate display to debug the problem.

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We have described the first two levels at which we use the display system: 1) warning indicator lights to flag anomalies, and 2) gauges or numeric displays to show more detail. The third level is a little bit unusual. We’ve written software that that pulls data off of the bus and stores it in a relational database. This allows us to check to see if the engine is running hotter than it did in the past in the same water temperatures or to see if the battery capacity has gone down significantly over the last year. We have all NMEA2000 telemetry stored every five seconds for multiple years now. Maretron has since introduced a device that supports this black box historical record so it’s now far easier to add this support to your NMEA2000 system. With the Maretron VDR100, it’s easy to have this support without going to the effort of a custom software implementation.

We’ve shown two of the Maretron displays that we rely on. In general we have the Maretron system showing one of two displays: the underway display shown above or the moored display shown below. The underway display focuses more on engine health and telemetry and anything else that matters when we’re underway. The moored display highlights data we care about more when at rest, such as weather conditions and inverter, shore and generator draw.

Click image for a larger view

The other three displays that we’ve designed are shown below. The first shows data specific to the power systems and the second shows wing and generator data. We use these displays when we want to dig a little deeper into something specific to those systems. We use the third display when doing something specific with our tanks, such as refueling.

Click image for a larger view

Click image for a larger view

Click image for a larger view

Maretron N2KView runs on our navigation computer in the pilot house. We also display the current Maretron screen on monitors in the salon and the master stateroom. These monitors simply mirror whatever is displaying on any of the four pilothouse screens but we usually show the Maretron display.

Click image for a larger view

Click image for a larger view

We also have several smaller Maretron-specific displays installed throughout the boat that hook directly onto the NMEA 2000 bus. At the aft helm and the flybridge we have a medium-sized DSM250 that displays navigation-specific information.

Click image for a larger view

Click image for a larger view

In the galley, a small DSM150 displays power-specific data. We use it to avoid overdrawing the 110V, 240V or generator. In a future article we’ll cover the load shedding system that automates power management and allows the user to just use appliances without having to worry about what other loads are currently in use. The auto-load shedding system just turns off the water heater or other less time critical power draw to keep everything else running. The yellow indicator light and the green one beside it in the image below indicate if the A/C or water heater loads have been shedded to prevent overdrawing the 240V system. These same indicators show on our ribbon. And the CHK box above the yellow box is the same big yellow/red check indicator as in the ribbon, so if the person on watch is in the galley they’ll see the problem right away.

Click image for a larger view

Click image for a larger view

We have a second DSM150 in the engine room mounted above the supply tank. This displays fuel tank levels of the four fuel tanks on Dirona. We use this data when transferring fuel and, during engine room checks, we can check this data against the sight gauges.

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Below is a list of all the physical devices on our NMEA 2000 bus. Much of the Maretron N2KView displays are based on input from these devices. We also have written custom software that reads and writes to the N2KView bus for functionality such as automatic electrical load-shedding.

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A final tool we use with the Maretron system is their N2kMeter. This does a physical check of the underlying NMEA2000 CANbus physical networking checking power levels, ground quality, and signal integrety. It also tracks and flags network errors. We’ve found it invaluable for tracking down and debugging NMEA 2000 bus issues. It’s rare that a networking problem emerges but, when they do, the meter allows the problems to be quickly isolated and corrected. For larger NMEA2000 networks, we strongly recommend this diagnostic tool.

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11 comments on “Maretron N2KView on Dirona
  1. Derek Doerr says:

    Hello James – I’m considering installing a N2KView systems very much like you’ve implemented, but am wondering about keeping the old analog gauges. Did the Dirona originally have analog gauges and, if so, what were your decision factors in either keeping them or eliminating them?

    Best regards – Derek

    • Yes, we still have the analog guages for the main engine and the wing engine in our upper helm area but those two analog displays are only there for backup. We normally wouldn’t use them. The AIS has it’s own head but it is mostly displayed on the Maxsea and Furuno MFDBB systems. The Pilot has it’s own head but there are backups as well. Generally, we aim to have all data available from multiple locations.

  2. Doug Bambauer says:

    Hi James, not sure if this is the appropriate place to ask a question, but here it goes. My wife and i are in the market for a N47 in the next 12 months or so. The European boats seemed to be priced so much lower than the domestic offerings even after converting currency. What is your opinion on buying a European vessel and how would you approach the in inherent electrical issues? Something tells me you will say “don’t do it”!

    Love to read about your adventures, keep up the good fun!

    • No, I wouldn’t be the slightest bit frightened of a 50 hz boat and, if it were $50k less, I would jump on it. We have a 60 hz boat but it’s spent the bulk of it’s life in a 50 hz environment and it works just as well in a 60 hz region as it does in a 50 hz country. With the right equipment and a thoughtful installation, you can be shore power frequency tolerant and mostly just not care about it.

      There are two big issues we all face when traveling in countries where the power frequency is not the native frequency of the boat: 1) appliances and electrical accessories have to be sourced from the host region, and 2) when plugging in to the non-host region, you need some way to manage the frequency difference.

      The first problem doesn’t feel that difficult. Just buy appliances from Europe if you have a 50 hz boat. We had to purchase some 60 hz electrical equipment when we were in New Zealand and this really isn’t much of a restriction. We just purchased from the US and shipped them — air frieght is not big deal. I wouldn’t worry about that one.

      The second issue is the more interesting: when plugging in a non-native frequency boat to shore power you need to manage the frequency difference. I’ve seen three broad options with many variants:

      1) put in a frequency converter and be able to plug in anywhere in the world,
      2) use a power design like ours where the shore power system runs large multi-frequency chargers and the rest of the boat runs off inverters.

      Both options require some electrical work. The first option is much more expensive but more of a drop in “just works” design. I favor the second approach because it’s more cost effective, easier to service than a “black box”, has more redundancy (single charger or inverter failure won’t stop the system), is roughly equal in efficiency, and is more general allowing a broader set of operating options like ability to run low voltage draw 240V appliances without the generator running. I’ve written up our variant of the second option in “A More Flexible Power System For Dirona” (

      I would be perfectly comfortable buying a 50 hz boat — with some investment and some skilled electrical work, you will end up with a design you can take and use anywhere in the world with many advantages aside from being frequency invariant.

      • Wayne Hodgins says:

        Gladly risking being repetitive allow me to add my thanks to you James for all the time and efforts which I know goes into creating and maintaining such a comprehensive and educational blog. My wife and I are finishing up what will be about an 18 month long design of our next boat which we plan to start building by mid 2017. We are two previously single handed world sailors who are now living, loving and learning “double handed” as we wander, ponder and wonder this awesome world in our 7th decade of life a d have decided to go for an all new set of adventures. You switching over to voyaging under power. Our new boat will be much closer to the FPB/Artnautica LRC/Black Swan Ripple style than a traditional Trawler being a long, low and skinny all aluminum hull but our systems and use case scenarios align very much with yours on my Dirona. My question, finally, and relevant to this thread is to wonder what you would do electric system wise if you were to be designing a new boat? Which I believe you may actually be doing? Specifically and as per your points above, I’m wondering what frequency you would go for with all your AC systems and loads? We are going to go for primarily 240v 50Hz and purchase our appliances and system equipment accordingly. We will have a small amount of 120v AC available for some inevitable electronics that will want that but these are all relatively low power devices and other essential pretty much unaffected by the AC frequency so will be easy to provide for with a small capacity Victron 120v inverter off our massive 24v house battery bank. The electric system on our current 52′ sailboat has evolved along similar lines and works very well for us. Our logic and use cases match up very close to yours as you most recently and eloquently articulated in your post about the “more flexible power system for Dirona”, though we are more rarely in marinas or have shore power and we will have massive amounts of solar rather than a generator. All my very verbose way of asking the relatively simple question, for now, of what frequency would you go for on your new boat? Thanks James!

        • Your new boat plans sound great and you both have a ton of experience. Neither of us have ever singled handed anywhere much less around the wrold. Two alone in a boat in the middle of the ocean forces a certain degree of independence but not nearly the way single handing must. I would find it difficult.

          Your question on boat power and frequency is an interesting one. If all you cared about was what was technically the most efficient, least weight, and safest, you would go with 240V. Smaller, lighter conductors and less heat due to less current at higher current conections. Higher voltage is more efficent. Eventually, higher voltage brings more risk as well but 240V isn’t materially different from 120V.

          Again, sticking with my theoretic “what is best” perspective, higher frequency is better than lower. So 60hz is slightly better than 50hz and many comercial applications use much higher frequency in niche applications. Sticking with “what is best and compatable with at least shore power somewhere, 60hz is slightly better than 50hz but the differenc is pretty minor.

          Focusing on the practical, 240V/60hz is pretty rare as a shore power voltage. It’s used in Papeete but it isn’t common. The reasonable choices worthy of considering are 120V/60hz or 240V/50hz. Many contries like south africa run nominal voltages of 220V rather than 240V but it mostly can all be lumped in together. The only time becomes a problem is on overloaded electrical systems where 240 under high load and saggig drops down to 215 and is still absolutely fine. But 220V can drop down below 200V and that is a problem with some equipment.

          If we only consider practical uses and not resale, I would go with 240V/50hz where we to make the decision again. It’s way simpler to just run 240V everywhere rather than having to have both 240 and 120 as we do. No matter what you chose, it’s going to “wrong” in many parts of the world so you have to design the boat to work fine whether in 50hz or 60hz countries. Given that both can work, most of the world is 240V, and it’s technically simpler and better, I would go with 240V/50hz.

          Resale is complicated in that the North American market devalues 50hz boats. That might cause me to lean slightly away from it but I’m really not sure. Given we generally make choices for our own use rather than for resale value, we might easily end up going with 240V/50hz.

          In a well designed power system, you just about don’t have to care whether your boat power matches the shore power when it comes down to plug in. With these modern electrical designs, you really just need your boat power to match that of the country where you want to purchase and service appiances and electrical devices.

          • Wayne says:

            Thanks very much for this thoughtful (as usual) response James, much appreciated. You confirm our experiences and thoughts as well and we’ll go with 240/50 as our primary AC and then have one smaller 120v inverter onboard for the inevitable few devices that need it. My wife and I are both rather “geeky” and techtoy lovers of all kinds and it seems like these are often first released for the North American market and so they are 120v/60 and we will no doubt want to have a few of these onboard. Cycles seem to matter less these days as I’m seeing more and more devices and appliances that list 50/60hz on their tags and our experience with running devices on the “wrong” frequency have been very good with very few problems. Similarly the shore power voltage has not been much of a problem for our current boat as we have a Victron Isolation Transformer which gives us great flexibility in being able to set it for any input voltage (110-240)and any output voltage (110-240). You make a good point about the NA market devaluing 50hz boats but like you we design/build our boats for us first rather than the next owner so while we do consider this, we will always put our use case ahead of the resale one where necessary. Thanks again for your thoughts on this and for sharing your wealth of experiences and knowledge. MUCH appreciated!

            • Yes, most US mobile devices will run fine on 240V/50hz with a plug adapter. Having a small 120V inverter allows you to be fully covered but much of what you will likely buy will run on either voltage. Your electrical system design sounds like it’ll support your needs well.

  3. Erik Andersen says:

    Hi James
    Thks for details on heating experience and your setup. Cold feet is a pain. Grateful for your comments. Enjoy ur sunday.
    Best regards/Erik

  4. Erik Andersen says:

    Hello James
    Thanks a lot for the detailed Maretron installation overview.
    It is indeed a marvelous setup and cover requirement for early-warning, detailed information on the individual sectors, so If something goes wrong you to know immediately where and what and have more information and historic data at your fingertips.
    Yes indeed Maretron will cover most needs.

    Thank you again for this information.

    Another issue for me is heating in the N52 under winter conditions (outside temps. below 32F / 0C). Understand you are living onboard and I wonder if the optional extra AC for N52 (Air Conditioning – (230v – 50Hz) Marine Air – reverse cycle with digital controls – 2X12,000 (VTD 12K) btu for salon, 1X16,000 (VTD 16K) btu for wheelhouse, 2X10,000 (VTD 10K) btu for staterooms – Total of 60,000 btus) has been sufficient for your needs. I would expect Scandinavia being not so cold as Canada. Or are just moving south …??
    Very best regards/Erik

    • Yes, for high lattitude cruising adaquate heating is vital. We use the 5 Marine Air reverse cycle systems when plugged in at the dock and when the generator is running but the go to heating system on Dirona when at anchor is large Olympia ( diesel boiler delivering hot water to each room in the house. Nice and toasty.

      When underway we use the Olympia system for heat but shut the boiler itself off and use waste heat from the main engine to heat the hot water heating system rather than run the boiler.

      We have been in areas so cold that we had to break ice to get to the anchorage and we have woken up surrounded by a thin layer of ice in the past. As the water temperature drops down into the low 40s and below, the reverse cycle system gets less effective so it’s nice to have a diesel boiler on board. I don’t recall many places we’ve been too so far where the reverse cycle system wouldn’t produce heat but, because we have the diesel furnace, that’s typically what we use in these conditions.

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