N2K fuel transfer control, aka the “Russ Gauge”
Last week, Offshore Systems announced a new NMEA 2000 Fuel Transfer Control that goes with its existing tank sensors and displays. For those vessels that use a day tank, this control can automatically stop a pump moving fuel from a storage tank if the day tank becomes 95% full. It looks like a well done product, but is particularly cool because Panbo frequent poster Russ Irwin was the customer behind the idea. Russ explains New Morning’s whole fuel scheme here. And I can add some color on the event that inspired Russ to inspire Offshore Systems, which was a transfer-related spill at the same yard where Russ’s sloop is being built. New Morning, incidentally, was launched three weeks ago and, though not yet complete, is looking good. Needless to say, Russ has lots of other electronics on board, not of all which are functioning up to Russ’s expectations, yet. More on that soon. Meanwhile, do note that the Offshore Fuel Transfer system controls the pump directly rather than via NMEA 2000; that makes sense now, as N2K switches and messages are still in development, but one day a control like this will do all its work via the bus (I think).
We have a very similar fuel system on Vision of Johanna (not too surprising considering the two boats are at least cousins if not siblings). When I looked into Fuel Transfer controlers back in 2002 the only options were $500+. No idea what the Offshore systems unit costs, but we just built our own relay control box using two easily replaceable and $10 relays. We had a nice plexi door’d teak enclosure so all up the thing probably cost $50, uses the high level alarm circuit built into the Xintex “Analog” fuel guage to shut off the pump when it reaches the top. Other than the first time we tried it (due to alarm circuit being wired backwards of what the factory had told me over the phone), it has worked perfectly. If any DIY’ers want to set this up, I have relay ladder logic diagrams as well as schematic wiring diagrams. Still, very good to see a nice commercial option for those without the marine engineering training.
I certainly can’t take all the credit. I sent the suggestion to Offshore Systems because I couldn’t find an N2K device last fall. Bruce Coward at Offshore Systems was very responsive. He sought additional specifications from Ron Young and JB Turner at Lyman Morse and then they ran with the idea, developing the product in just over six months.