Re: [Amel Yacht Owners] Re: Original Autopilot Integration With New Chartplotter

Stephen Davis

Hi James,

I probably have one of the more unusual setups in that I have all of my old B&G instruments, and a modern Raymarine system as well. Maybe it is because of my airline pilot background that I like redundancy so much. We even have a 2nd raymarine wind transducer mounted on the mizzen mast. I was skeptical that the mizzen transducer would be all that accurate, but it has proven to be every bit as good as the B&G wind mounted on the main. About 2.5 weeks into our Panama-Hawaii passage, 2  VLSBs (Very Large Seabirds) managed to break the B&G transducer off the main one rough night. It was worth it's weight in gold to still have wind information while hand steering the last 1200 miles with the emergency tiller. The reason we could see the wind instruments at night while having to steer from the edge of the aft coach roof was because of the very bright and readable display on the Raymarine I70 MFD.

This is a rundown of how we upgraded the electronics our 1992 SM after we purchased her in early 2014:

  • When we purchased her she had a newer RM SPX30 autopilot, and the original autohelm rudder reference and flux gate compass. We added a new Ray EV400 autopilot, compass sensor, and a 2nd control head at the helm. We used the same A/B switch documented by Bill K on his site to switch between autopilots. The older boats do not have a linear drive, and I carry a spare rotary drive. It takes me 30 minutes to change the drive out while underway, and yes, I have done it. We will be installing a linear drive while we are in Hawaii. I'll add a 2nd A/B switch for the drives. One important note is that with a linear drive, we could have steered the boat with the autopilot after the racks froze the steering. Also, our rudder reference unit (original Autohelm) failed last week after 26 years of use, and I replaced it with the new unit which came with the EV400. I'll buy another as a spare, as neither autopilot will function without one.
  • When we hauled the boat in late 2014, I removed the small thru-hull transducer for the defunct forward looking sonar, enlarged the hole, and added a networked Ray tri data (speed, temp, and depth). At the same time, I added the 2nd wind transducer on the mizzen and a RM I70 right next to all the B&G instruments at the helm. I really like the I70, as it is configurable to display almost any data you have, and is bright and easy to see. These additions gave me redundancy in depth, wind, and speed.
  • In 2017 while in St Maarten, I brought back some new gear from the USA, and continued the upgrade. I removed the 10" Furuno chart plotter from the helm and the 7" at the nav station. I added a RM ES127 (12") at the helm, and an ES7 (7") at the nav station. They work essentially the same, and we have been very pleased. Either RM MFD can operate as an auto pilot control head, and we removed the 2nd autopilot control head and put it into spares. We bought a 2nd I70 display, and filled the hole with that. We also removed our recently failed Furuno radar, and replaced it with a RM Quantum Chirp radar. One big advantage to all these new electronics is a dramatic reduction in the amount of amps used. We used to leave the radar in standby at night, and turn it on every 15 minutes for a quick scan. We don't even bother to turn it off now, as the amp draw is minimal. All of the RM gear and our 2 Vesper Marine AIS transponders are on the Seatalk NG (NMEA 2000 with a different connector) network. All of the B&G gear is not networked, and I see no reason to change that.
  • When we purchased Aloha, she had an LCD B&G Hydra 2000 FFD at the nav station, and one at the helm. At the helm we also had analogue wind direction, wind speed, boat speed, and depth. The depth transducer failed in 2016. This transducer is a smaller diameter than what is common today, and after some research, we were able to source a replacement in the UK. The depth now works fine, and I expect that system to be reliable for many years to come. When the birds broke our wind transducer, I was able to purchase a lightly used replacement from Ebay for less than 1/2 the new price. We have recently purchased used and rebuilt and certified by B&G a spare Hydra 2000 FFD and the B&G processor that drives the system for a total of $350. My hope is that with these spares, I will have the B&G instrument functional for the time we own the boat.
  • Last but not least is the boat computer we installed in 2015. We built a small DC powered computer on an ITX chassis, and installed a 27" Samsung monitor on a swing out mount. The monitor is also directly powered from DC, so we are not draining amps going through inverters. The computer has a SSD drive, is mounted on a slide out shelf at the nav station, and the monitor is mounted on the bulkhead between the nav station and the salon. The monitor can swing far enough to watch movies in the salon, or be near the companion way to view charts. Our Vesper AIS has a USB output which goes to the computer, and we get position and all network data on Open CPN when it is running. We also make our own Google Earth charts which can be viewed on Open CPN with the big monitor. All in all, it is a slick system with low power draw.
I'm sure many of you think all this is overkill. I'm perfectly capable of sailing most anywhere without most of this gear functional, but it sure is nice to have. With careful planning, purchasing, and doing all the installs myself, I have very little money invested in everything, and really enjoy the redundancy. This is only one way to do things, but after a lot of miles covered, we are pleased with our system.


Steve Davis
Aloha SM 72
Ko Olina, Hawaii

On Sun, Aug 5, 2018 at 1:19 PM greatketch@... [amelyachtowners] <amelyachtowners@...> wrote:


When it comes to spares and backups we are all informed by our experiences, prejudices and fears. It's hard to approach with total logic because we really don't have much reliable data about failure rates and causes.

One of the downsides to the NMEA2000 network is that it is all "of one piece." Although it is designed to be robust and fault tolerant, I have seen one corroded connector bring down a big piece of a boat's network.  It's probably a good idea to have a couple spare connectors, and a spare terminating resistor for a NMEA2000 network just in cast you need to bypass part of the circuit.

I do not have any bad experiences with rudder angle sensors, but all of the ones I have used were "dumb" ones hard wired to the course computer. They are simple circuits, and as long as they are kept dry, with good connections, they SHOULD work. On the other hand, without a working sensor, the AP is not usable...

Adding the complexity to have the rudder angle sensor connect through the network makes things...more complicated.  Our two independent AP computers have separate rudder angle sensors so I haven't really felt the need to think hard about backups for that part.  I do carry a complete, drop-in spare, linear drive.  So we have three drives, two computers, two rudder sensors, and two fluxgate compasses. Short of getting struck by lightening, we should be in good shape.

The only part of the system that we have deliberately kept independent of the NMEA2000 network is the backup AP.  If the network totally died, we would still have the ability to steer to a compass course with the older course computer.

We travel with enough hand held devices that include GPS receivers, and paper charts that even serious network problems would be an very annoying inconvenience, not a disaster.

I know some people love their forward scanning sonars, and for good reasons.  If I spent a lot of time cruising in rocky areas like New England I'd likely be more interested. For us, all of our "ground contact events" have been in gradual shoaling areas where we were well aware of the depth. When the forward scanning units get to the point they can help me find a 2.05 meter channel surrounded by 1.95 meter shoals I'll be all in!  

Theoretically, the forward scanning units would allow us to move through coral head infested waters without needing to be as attentive to time of day and visibility, but I am not ready to turn over that task to electronics. If we are doing the eyeball navigation thing anyway, the added value of the electronic version doesn't push it high enough on my wish list.  Don't get me wrong, these things are on my wish list, they just haven't quite gotten to the top of the priority list in the competition for available resources!

When my sailing students asked me some version of the question, "Do I need "X" on my boat to go cruising?" I asked them to do a thought experiment.  Imagine you are at anchor in the lagoon of an isolated tropical atoll.  Device "X" has just irreparably failed.  Can you get home?  If the answer is "Yes" then device "X" is a luxury.  One you might very much want to have, but in the harshest of analyses--a luxury.  If the answer is "No" and you would be stuck in this remote location until device "X" is working again, then you need two of them! 

Bill Kinney
SM160, Harmonie
Annapolis, MD, USA

---In amelyachtowners@..., wrote :


   I like your concept of having some stand alone instruments and would like to learn of a good way to have some of the benefits of the network without being reliant too on it .  I will be buying most everything new for my boat so have lots of options so long as I don’t blow the budget. (grin)   If you have any thoughts or suggestions on achieving a good balance between the standalone and networked items please share.    I am using a Zeus 3-9 as my plotter and was thinking of adding the B&G 4G radar.  My instrumentation is the original B&G Analog style which mostly still work.  The wind was replaced by an Advansea unit that still works fine but I think is being phased out.  I really like the idea of the forward looking sonar but wonder if the range and accuracy might improve if I wait a while on that one.  I have two backup chart plotters that are standalone plus a handheld.  I only have the original rotary autopilot which works fine so far. Would you recommend carrying a spare rudder sensor?  Beginning to get the boat ready for the trip from the Med. back to Florida.


James Alton
SV Sueño
Maramu #220,  about to begin another season in the Med!

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