DMK box hand’s-on #1, developers needed!


Even if it only happened in my basement lab, it really is wonderful to see a boat’s sensor data arrive wirelessly into an iPad app, where it could be used and displayed in so many ways. The instrument screen shown above was developed by the same DMK Yacht Instruments folks who build the WiFi box that got the data there (first discussed here in December). The wind, depth, and speed numbers went into the DMK gateway in NMEA 2000 format, but they could have been in NMEA 0183 or SeaTalk, or a mix of all three. In fact, I’ve tried all three source formats with some success so far, but I’m frustrated because the DMK app — meant mainly for configuring the box, I think — only displays the values shown fully, and no other app I know of yet takes full advantage of what the box can do. Lets hope some developers start paying attention to what’s possible here!

My test setup below may look scary but I’m using every option available on that rainbow ribbon cable coming out the DMK box at left. Starting at the top (white) junction box, the upper right cable has four NMEA 2000 wires supplying power and data. Then there’s a SeaTalk data cable I can connect to the set of Raymarine ST40 sensors and displays that I first used to test Ray’s ST-to-STng converter. (I’ll show off that rig soon as now I’ve got it accessorized with a fan for wind and a water tube for depth, and I’ve been also been using it to test the ability of the new i70 instrument display to understand SeaTalk data.)
  At any rate, the black junction box connects the DMK’s two NMEA 0183 ports with the Tacktick 0183 Interface and a SRT AIS receiver (from before the latest generation). I won’t go into all the N2K data types and flavors I can put into the DMK box, but let’s just say that I’m ready to test some marine apps that are programmed to receive data from a boat!…


But there’s the rub, right? So far, iNavX has pioneered the boat-to-app navigation relationship (with Maretron on the systems side), but its developer Rich Ray has to sleep sometimes. And whereas the standards for putting 0183, 2000, and ST onto Ethernet are slim to none, he has to program iNavX for each kind of bridge, at least to some extent. I am impressed that the NMEA 0183 wind data coming from the Tacktick via DMK does show up in iNavX, and I suspect it will show most 0183 data (though I’m having trouble with AIS). But the gibberish seen in the TCP/IP window below is misunderstood SeaTalk data, and I think it’s quite reasonable that Ray doesn’t intend to support NMEA 2000 via the DMK box until he sees if all his recent work getting iNavX to understand N2K from the Chetco SeaSmart box(es) earns some “traction”.
   I’m very close to testing iNavX with SeaSmart, and have high hopes, but isn’t there room for lots more developers here? For one thing, the DMK box has valuable configuration and data analysis features I’ll go into in another entry. And I think that Navico’s recently announced GoFree plan to make all its system data available to third party apps via WiFi/Ethernet should be a real motivator for developers to get going now. Maybe I’m obsessing on the value and future of connecting marine electronics to mobile devices, but couldn’t all charting, racing, weather, and system monitoring apps benefit? And apps I haven’t even imagined yet?  Your thoughts please.


Ben Ellison

Ben Ellison

Panbo editor, publisher & chief bottlewasher from 4/2005 until 8/2018, and now pleased to have Ben Stein as a very able publisher, webmaster, and editing colleague. Please don't regard him as an "expert"; he's getting quite old and thinks that "fadiddling fumble-putz" is a more accurate description.

21 Responses

  1. Ben Ellison Ben Ellison says:

    Chetco just put up a relevant press release on the iNavX support:

  2. Sandy Daugherty says:

    I’m beginning to understand the potential that wifi tablets offer to do more than display data. Is it safe to think that the acquisiton and integration of such diverse data could lead to tactical displays for racing? If so, are cruise route planners that can take into account changing weather conditions and derived current data, that far away?
    While the integration of all the relevant data would challenge the wetware of a moderately experienced sailor, (a very experienced Captain might make the right decisions by intuition) such number crunching would hardly strain the modest computing power of today’s tablets.

  3. Ben Ellison Ben Ellison says:

    Absolutely YES, Sandy. In fact, today I just tried an app called iRegatta which can at least get the Tacktick NMEA 0183 wind via the DMK box. I’ll figure out way to put more 0183 data into the DMK.
    iRegatta looks quite capable, but I’m not sure the developer is interested in supporting NMEA 2000 just yet:

  4. rxc says:

    If you get all of this data into an iPAD, is there some way to get it out, other than sending it “thru the cloud”?

  5. GPSNavX says:

    iNavX will send out the active waypoint information via NMEA-0183 sentences to the WiFi connection. Typically this is used to communicate with an autopilot connected to the WiFi multiplexer.
    For a list of the data (N0183 and N2K) iNavX supports, visit this link ..
    Native N2K AIS will be supported in the next iNavX release.

  6. Ben Ellison Ben Ellison says:

    I don’t think the DMK box does any communications back to the boat as currently programmed. The Chetco box is two-way on NMEA 2000, at least for some PGNs. This makes for some interesting possibilities but is also potentially dangerous to the boat’s system.
    There are useful ways to use the “cloud” for apps like these. Logging data and automatically sticking it in your iTunes folders is one that iRegatta has just added.
    By the way, I didn’t mean to exclude Android from this discussion.

  7. Quitsa says:

    I don’t want to seem negative, but I have a hard time understanding what one would do with such a system other than on a relative big trawler or cruising sailboat on which the crew or captain might be below decks and want access to the information (which perhaps is the answer to my question). My two NavNet 3D 12″ displays are so much brighter and less vulnerable than my iPad and of course can operate all the nav, radar, and sounder functions.

  8. Ben Ellison Ben Ellison says:

    Smell the coffee, Quitsa! It will be a long, long time before I forsake dedicated MFDs, too, but I can easily envision secondary uses for apps phones and pads on all sorts of boats. Primary too.
    For instance, there are already early-adopter smaller-boat folks, particularly racing sailors, going to a combination of, say, a Standard Horizon AIS Matrix VHF and a mix of 0183 GPS/depth/wind/etc sensors all funneled through a gateway to iNavX. The hope is a lightweight system with a lot of bang for the buck and a lot of room to grow.
    Meanwhile, MFDs are developing close relationships with mobiles. I’m going to love going down to the boat with routes, chart updates, user-generated POI data, etc. already downloaded on my phone or pad and having it all sync up to the boat system automatically. But I’ll also want the live boat sensor data coming back to the mobile so I can extend the system to whatever neat app a developer can come up with.
    And let’s not forget that once a boat’s sensor data is onto Ethernet, it can also get ashore through one of many pipes. Be it for security or family tracking or just peace of mind.
    And, finally, does anyone doubt that there will be bright, weather resistant, and reasonably priced mobile apps devices sooner or later?

  9. Ben Ellison Ben Ellison says:

    More apps that connect with your boat, thanks to Pacific Yacht Systems (good blog):

  10. HenryD says:

    I think your mention of your MFDs and iPad makes me think you already see the future…one where my system (PC, MFD, radar, AIS, weather, etc) combined with my NMEA2000 data is on a tablet or two which are portable around the boat. The iPad is a first gen tablet that finally has the industry looking and thinking differently.
    As I am looking to replace my MFDs but am waiting for the broadband radar to interface to a PC chartplotter – Rosepoint or other. I like the redundancy of two or three tablets mounted on the helm. I am using an iPad and a ASUS EP121 tablet now but am eagerly waiting for the next products from CES this week and coming releases. It’s hard to think how fast things are changing and how early this shift we are in – the iPad has not been around long.
    As far as the “cloud”, I think there are some uses for this such as how the SPOT puts data on Google Maps or allowing me to look at my Maretron systems from anywhere I have internet access.
    Just my two cents

  11. Ben,
    FYI – the TackTick interface box in your photo caught my eye, but when I tried to follow the links from the previous Panbo articles, they were all dead links – apparently, TackTick has been aquired by RayMarine!

  12. Mark says:

    There are quite a few apps out there that can give you marine data over WiFi. Some of my favorites are Maretron N2KView, Skippers Eye, iNavX, DMK Marine Instruments, Marine Instrument Display+WiFi, Digital Yacht iOnboard, NMEA Remote and iRegatta.
    DMK Marine Instruments hardware is unique in that it will accept NMEA 2000, 0183 and SeaTalk data all at the same time. DMK can also use either TCP/IP or UDP protocol.
    Some of the features I would like to see in a display app are: Customizable font, color and size, multiple protocols, night display mode, accept any NMEA senetence, customizable meter combinations, digital or analog display, able to display internal location services data and ability to display video.
    Ben, you are right, we need more app developers to take advantage of all this data and display it in new and innovative ways.

  13. Quitsa says:

    Probably my viewpoint is colored by the fact that I am running a sportfishing boat so the only two places I need access to data is at the lower helm where I have the two big MFDs and up in the tower. Thinking about it some more, it would have been very nice and probably a big cost savings if I could take an iPad like device up to the tower that had access and operational interfaces to everything at the main helm and did not need to put a dedicated MFD and autopilot control up in the tower. That would have to be one fine sunlight viewable tablet, however.

  14. JPDillard says:

    I just found this site, and this topic is germane to my current interests of upgrading my older (1985) Wauquiez 38 to cutting edge technology.
    In this regard I am installing an Iridium satphone with the new wireless card option that allows wireless communication through an ipad app for email and slow (very) websurfing. Weather from the 4D app is displayed on the ipad using GRIB data received wirelessly through the sat phone. The INavx app will also display imported GRIB data, but the 4D app is much more intuitive and the display is incredible.
    The Inavx site recommends interfacing with a wireless multiplexer, and mentions the Brookhouse and Digital yacht devices, but does not mention the DMK-11 product, the subject of recent posts on this site.
    Does anybody have any experience with these devices? I would lean towards the DMK device to support a local manufacturer, and to facilitate tech help, all things being equal. The price is similar, around 400 bucks.
    Lastly, I have the issue of different brands on my gear: Furuno GPS, Plotter, radar, AIS, but Raymarine x5 autpilot. I’d like to be able to control the autopilot through the inavx software. Is this possible?
    Any thoughts would be appreciated.

  15. Rob says:

    The problem I see here is the size of the market. I am one of those developers that could bring to market a high quality app to display boat data, etc., but it needs to be a commercially viable proposition for me to pull the trigger. For example, is there a single compelling use case? If so, what kind of price and volume are we looking at? Plugging a sat phone into a tablet for pulling down GRIB weather data offshore is a highly compelling use case, for example. Is there one for putting boat data onto a tablet? Any ideas here?

  16. Dennis O'Connor says:

    Hmmm, I’m beginning to wonder if we are boating or playing video games?

  17. Ben Ellison Ben Ellison says:

    “…couldn’t all charting, racing, weather, and system monitoring apps benefit?”
    Rob, I know there’s at least some interest in apps that look like regular boat instruments, but the point I was trying to make is that all sorts of marine apps could benefit from connection a boat’s sensors.
    I don’t know about gross dollars, but I see that iNavX is #41 in the top grossing Apps Store navigation category. Not Angry Birds money, I’m sure, but maybe not bad?
    Finally, isn’t it true that there was no clear use case for the iPad itself? Wasn’t part of Jobs’ genius the ability to envision things we “need” before we knew we needed them?

  18. Sandy Daugherty says:

    Dennis; you forgot to say “sniff” at the end of your Hmmmm! Let me put all this in perspective.
    After every major or minor innovation in the history of going to sea, The talk around the Grog Cask has been divided along the beard line, that which separates the gray beards from the no beards. Not too surprisingly, the Gray beards consist of those who acquired the moniker naturally, by surviving a few hair raising adventures, and those who aspire to this aura of superiority by talking like a pirate and chemically enhancing the distinguished hue. One can become a no beard by bathing more often, and shaving.
    Even the question of bathing once drew the beard line in the sand, with the Church standing tall on the no-bathing side.
    Lets cite a few historical examples of the beard line:
    The sun stone. The magnetic compass. Steam propulsion. Synthetic cloth and rope. Indoor plumbing. Wooden ships and iron men. Fiberglass.
    Some innovations caught on faster than others: Celestial navigation. Gunpowder. Vitamins. Anesthetic dentistry. The Internet. TV remote controls. Zippers.
    Others just went away: Instant Coffee. Celestial navigation. Beta video recorders. Quadraphonic sound. White plastic belts and shoes. Leisure suits. Big hair. Masts named for the days of the week.
    There will always be a beard line schism, and there will always be brave challenges as one or the other crosses the line to start a brawl. Panbo is a no beard haunt. Largely non-confrontational, we agree that innovation happens, that some of it will stay, some will go away. Most of us are boaters. Few of us need to assert our manhood or saltiness. We reveal our ignorance or competence by what we write, not by pretense.
    I think you find yourself in the wrong bar. If you aren’t interested in innovation, intrigued by the minutiae and aroused by a slick new gadget, you’ll find little to interest you here.

  19. Ben Ellison Ben Ellison says:

    Thanks, Sandy. I may be addled but the relevant phrase that comes to mind is the title of an old Firesign Theater record: “I Think We’re All Bozos on This Bus”

  20. Jeffrey Siegel says:

    I think the largest “use case” for these extra displays hasn’t been mentioned here yet – planning.
    Given that a nice built-in, dedicated MFD type of chartplotter is the consensus for piloting (and that includes a nice, dedicated PC running a high-end application), the underway use for an iPad isn’t fantastic. It makes a nice backup but that’s about it.
    But as a planning tool on and off the boat? An iPad and even an iPhone or Android tab/phone is killer. What’s needed is the interface capability back to the boat for execution of the plan on the MFD – that’s a nice missing link on many systems. DMK and Chetco are mechanisms for making that link.
    I think there’s another “companion” use while underway for these other displays (and TV’s) – we’ll see how that grabs later in the year.
    As for developer/Rob, I’m reminded of a quote from hockey legend Wayne Gretzky: “You miss 100% of the shots you don’t take.”
    When asked why he was so much better than other players of his time, he also remarked, “I skate to where the puck is going to be, not where it has been.”
    So if you’re waiting for the market to tell you that a need exists, it’s already too late when they tell you. I’ve never started a project or company unless I totally believed in the product and could find at least 10 people who told me it was a dumb idea. That always let me know that I had a shot at it.

  21. Dennis O'Connor says:

    Heh, heh Sandy…. On your list of innovations that just went away; I went through all of them except for the one – I never had a boat with enough masts…
    So yup, I’m a beard, but not a troglodyte… I like my GPS/MFD in my boats and my planes… My car too, for that matter…
    Well yeah – find a need and fill it and you are in business… But that need is only unfilled because everyone else thinks they don’t need it – so ya gotta surprise them with a want they didn’t know they had… Did much of that for the last 50+ years… Lost a bunch of money but boy did I have fun… The wife put her foot down and said no NEW companies, I’m sick of you working 14 hours a day… Hmmm, so I licked my wounds for a bit, didn’t like the stock market, so I dug up some cash and bought some farms… She may yet speak to me again before judgement day – or maybe not.
    And speaking of electronics, you ought to see the tractor without a driver pulling a grain wagon and following the combine around the field like a puppy on a leash and when the wagon is full that tractor runs itself back to where the semi is parked for unloading…
    So, I stand corrected – a beard like me just doesn’t understand… I’ll be quiet…
    cheers – denny-o

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