So yesterday I FINALLY figured out what exactly Furuno meant in their manuals for installing the PG500R “Rate Compensated Heading Sensor” which ships as part of the Navpilot 511 Autopilot system.
I thought it was me, I thought I just wasn’t getting it. After all how could these new, state-of-the-art devices actually rely on NMEA 0183 to talk to each other (and everything else) when the rest of the super-slick Navnet 3D products are using far more up to date technologies like NMEA 2000 and Ethernet? To me it read like Furuno was expecting me to throw a “bearskins and flint knives” solution on board the Enterprise. It just was not logical.
Turns out I was right – it DOES make no sense. The Navpilot 511 and the PG500R simply do not speak modern networked instrument protocols. It is NMEA 0183 all the way.
** Technical Interlude **
To the non technical, non sailors who might be reading this (Hi Mom!) you might be wondering “What is so appalling about this NMEA 0183 thing anyway? What about it offends you so?”
In short, it is a communication standard for electronic devices set by the National Marine Electronic Association (NMEA); it was the cat’s meow back in the 1980’s. It is fairly slow and fairly limited and frequently involves soldering or twiddling with tiny little wires and cross connections and “bridges” trying to figure out which is “Talker+” and should be talking to the other Talker+, or maybe talking to Listerner+. On one hand, it is fairly simple…because it is fairly limited. It also does not include a power source, NMEA 0183 devices speak over NMEA 0183 but they need their own connection to batteries.
The NMEA released a new standard called ‘NMEA 2000’. It is much faster, has standardized cabling, uses more advanced protocols and offers a whole lot more of options and power to the equipment network. NMEA 2000 (or N2K) also provides power over the network, so most (but not all) N2K devices just need to be plugged into the network. If they do not drain too much power they need no more external wiring or fusing – it’s plug it in and turn it on.
Ethernet is the same basic protocol/network that has been used in computer networking for the last 20+ years now, that it is finally becoming almost de rigeur in marine technologies is more of a comment on the state of marine tech rather than the network itself. But it is fast, easy, and ubiquitous – almost every one of you reading this is connecting through Ethernet somewhere in the mix.
NMEA 0183 = cranky, slow, archaic but with small wires, NMEA 2000 = fast, simple and powerful…big fat cables but with power.
So – what is my bitch? Easy – THIS IS BRAND NEW AND VERY EXPENSIVE STUFF, IT SHOULD USE THE LATEST PROTOCOLS. The NavNet 3D gear on the boat all talks to itself over Ethernet and can use N2K data – why can’t the autopilot? Why has Furuno not updated this yet? To get this device talking to the rest of the boat I need to run another NMEA 0183 cable half the length of the boat and wire it in so it can talk slowly to the rest of the gear.
It gets worse though, because my original plan was to have this snazzy new “Rate Compensated” compass supply the default compass data for my network. This allows the Radar/AIS combo to use something called ARPA (Automatic Radar Plotting Aid) to calculate possible intercepts and collision course from target data on the radar. It also would allow me to look at a monitor in the middle of the night to see if the boat has changed directions or swung at anchor.
Unfortunately the default wiring for the compass with the autopilot has the compass get powered by the autopilot. No power to the autopilot = no compass. And of course it also relies on NMEA 0183 to get the data to the Radar/AIS, possibnly even through the autopilot. It CAN be powered independently (like I want to run another power lead to it…not) but it is not designed to do so when used with the autopilot.
Of course this is not an acceptable solution, I have no desire to leave an autopilot powered on all night to get a compass heading on a data display, it is a huge waste of power even if the Autopilot is on Standby mode. They should be independent, this is a throwback to the bad old Raytheon days when the Seatalk bus got all of the power from all of the instruments from the Autopilot processor, you HAD to have the A/P on if you wanted to see wind direction for example.
The upshot of this all is that I decided to add a sensible, modern compass to the mix so I picked up a Maretron SSC200 Solid State Rate Gyro Compass. This appears on the surface to be a far superior product to the Furuno PG500R. Even if the Furuno is capable of more frequent updates the Maretron speaks (and is powered by) NMEA 2000. Additionally the Furuno is very cranky about which orientation you install it in (must be on a horizontal surface pointing forward…not always easy to find in a boat) whereas the Maretron can be installed in pretty much any orientation so long as you configure it accordingly.
Being a belt and suspenders sort of guy myself I am not offended by the concept of extra electronic compasses on board – I’m all for redundancy. But I am offended that this technical offering does not integrate with the rest of Furuno’s fine navigation hardware. In truth I could have used ANY autopilot and it would not have mattered one bit since it is all over NMEA 0183 and offers no real integration with the rest of the electronics suite.
