Raymarine LightHouse 3 calibrates Oceanic Systems tank senders, on my float mate’s boat

Way down the long list of new features that came with April’s LightHouse v3.9.46 for Raymarine Axiom MFDs is “Tank naming and Sender Calibration” and it turns out that means NMEA 2000 tank senders made by Oceanic Systems. Which is a semi-big deal because a significant disappointment of N2K is that while many standard data PGNs are truly plug-and-play across brands, sensor calibration is usually not. What’s more, I learned about this from my friend and Camden Harbor float mate Jud Sawyer, and I got to attend the semi-exciting proceeding.

I sometimes thank Jud on behalf of the marine electronics industry because while being a true frugal Mainer he also enjoys treating his well-aged Shannon Brendan 32 to some tasty technology, and his taste (and DIY skills) are well-honed from a lifetime of engineering and tinkering. Nonetheless, he did not at first realize that the potentially accurate Oceanic tank sender info he hoped to display on his very capable Garmin GPSmap 1222xsv could not be calibrated by the Garmin.

For a while the possible options were sending the senders and tank measurements to an Oceanic dealer for volumetric calibration or buying Oceanic’s 4-inch 3345 display. But then he learned that the job could also be done by a similarly priced Raymarine Axiom 7 — thanks to sales volume, not liquid — which could also do a whole lot more on the pontoon boat he trailers to lakes.

So when we rendezvoused last Saturday morning, Jud had the Axiom and the port tank sender temporarily installed on his NMEA 2000 network while the starboard sender was fully installed in the new and empty starboard tank. (How the port sender gets fitted into the tank that doesn’t need replacement remains a mystery). He’d also lugged in a lot of full five-gallon diesel jugs.

One of the first things we learned was that 14 is not actually the right number of calibration points for a 70-gallon tank divided into five-gallon increments (because point 1 is zero). Once Jud set that number to 15, the Axiom asked for the first five gallons (instead of 5.38) and he was off. Drain a jug, press OK, drain another, press OK, repeat, repeat, repeat, go to the marina for refills, and repeat.

I’ve seen more flexible tank calibration routines — like how Gizmo’s CZone Signal Module tank settings can be tweaked at any time for any known fluid level, and also saved as a file in case of module replacement — but credit to Raymarine for a pretty good start. You can find all the details well explained the LightHouse 3 v3.9 Advanced Operation instructions (PDF), starting on page 77. And, yes, configuring a rectangular tank is much, much easier.

In Jud’s case, the next step was making sure that the tank level information got to the Garmin which will stay on the Shannon, and I got to show him how Menu/Edit Gauge Pages let him select which tank showed where. The hoped-for “100% Full” on Tank 2 (aka “Starboard Fuel Tank,” which can also be specified on the Garmin) got him grinning, and I suspect he’ll also grin when he gets to check the Garmin’s fuel used number against his next fill-up.

Then again, I felt obliged to explain what’s required to install his recently purchased Maretron fuel flow monitoring system — either a Maretron USB100 bridge and laptop, or a Maretron DSM — and how’s he going to end up with two possibly discordant counts of fuel used, remaining, and so forth (as I went on about here). But here’s the bottom line: we both enjoyed a good Saturday morning on our float.


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.

8 Responses

  1. Grant Jenkins says:

    Another interesting article, Ben – I’m sure lugging around the 5-gallon jugs was the least fun part! I recently calibrated a couple of 35 gallon tanks using Wema (now KUS) sending units and Simrad’s NMEA 2000 Fluid Level sensors, with good results – but instead of the 5-gallon jugs, I simply timed the water flow at a fixed setting into a 5-gallon pail – once the GPM is calculated, it’s amazingly accurate, and a lot easier than carrying and pouring from jugs! Of course, this requires a hose nearby….

  2. Don Joyce says:

    Thanks for posting this Ben! I have the Oceanic tank sensors on my day tanks since 2010 to be able to monitor when its time to refill them. Does the calibration work N2K system wide, or only on the Raymarine Axiom?


    • Ben Ellison Ben Ellison says:

      Don, I’m nearly positive that the calibration values live in the Oceanic senders. And I’m positive that the Ray Axiom 7 used for the calibration in this case was shut down and removed from the N2K network when I photographed the Garmin displaying the 100% tank 2 reading.

      • Bruce Coward says:

        Hi Guys,

        The calibration points live in the senders and can be calibrated at the factory at no charge when being purchased or from Oceanic Displays or now directly from the latest Raymarine Axion software.

  3. Don Joyce says:

    Thanks for the clarification. The reason I asked is the senders could have been calibrated before with “full and empty”. If so they would also show 100% when full. I suspect they come from Oceanic Systems that way. They of course would have to be calibrated again if the sensor tube were cut.

    I need to update the dinghy chartplotter. another plus for choosing an Axiom which I can easily patch into Cat’s Meow N2K network for calibration..


    • Ben Ellison Ben Ellison says:

      Don, you are right to be concerned since some systems like Simrad’s can add calibrations to other brand N2K sensors like wind and speed that do not live in the sensors. So you get the calibrated wind speed on the Simrad displays but not on other instruments displaying the PGN coming directly from the sensor.

      Maybe the Raymarine manual I linked to is specific about this, but I’m very doubtful that Ray is keeping the calibration within its own system. For one thing, it would be hard to add irregular tank shape calibration to whatever simple values the Oceanic sends out by default — while it’s easy to, say, add a +/- % correction to wind speed, or a direction offset. For another thing, I understand that NMEA 2000 has always included a Command PGN meant for sensor calibration like this. It just hasn’t been used much between brands.

      Maybe you should contact Raymarine or Oceanic to be sure.

  4. Bruce Coward says:

    We have always held that calibrations should be in the senders so every manufacturers display shows the same value.

    • Ben Ellison Ben Ellison says:

      Thanks for the clarification, Bruce, and also for doing it the way that is ultimately best. And congratulations on the relationship with Raymarine. Can I hope that we’ll eventually see it with other display manufacturers?

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