Installing a B&G H5000 System in our J Boats J/46

We first noticed that our autopilot wasn’t up to the challenge of big winds and big waves on our trip from the Bahamas to St. Thomas. We took off to make the non-stop 700+ mile trip on a January nor’easter to make a downwind dash.

We enjoy sailing in weather windows like this. Cruising in a big breeze downwind is really fun, but boat handling, especially with only two aboard, can become a challenge.

That is why most cruising couples and single-handed sailors put so much time and effort into their self-steering solutions. Not only is reliability and performance a concern, but also redundancy.

Old vs. New Autopilots

Our 20-year-old Roberson AP22 was incredibly reliable. Its performance wasn’t up to snuff when we were getting tossed around in large waves or sneaking along in light air swells. Its wind steering features couldn’t keep up, and it lacked speedy compass data and other important data that can help the boat steer.

This is where the new generation of autopilots and instruments comes in. The core is a more accurate compass, along with better processing power to react to wind and wave data.

We spent a year or so looking at a few different options, including NKE, Garmin, Raymarine, B&G, and DIY (do it yourself via RPi, etc.). We tried a hybrid B&G H2000 and NAC-3 system, but we couldn’t get the wind data to jive reliably. An update to the firmware helped, but I am convinced it has to do with the way B&Gs NAC-3 is coded to receive wind-related PGNs, as it did not like N2K data through the ActiSense NGT-1.


Pros and Cons

We finally settled on the B&G H5000 Hercules system. Here is why:

  • Pitch and Roll Corrected TWA
  • Works with our existing H2000 wind and speed sensors (no mast wiring and no haulout for a new thru-hull)
  • Gust response
  • Configurable performance levels
  • Race-proven reliability
  • Experience and familiarity with H5 from racing OPBs

The big con was we could not use our existing B&G H2 Hydra processor and displays with the H5 pilot. This meant going to an H5 CPU, which, because there is no way to back convert to Fastnet, also meant we had to upgrade all of our displays to NMEA 2000.

This is an expensive and time-consuming proposition. In my opinion, B&G should make a backward compatible converter to Fastnet. It would sell fewer displays initially, but it would surely help ease many into the upgrade vs a possible total switch to a competitor.

What we needed to buy

Once we decided the project was a go, we had to go all in. We spent quite a bit of time shopping and pieced the system together from multiple vendors. Here is what we removed, and replaced it with:


  • B&G H2000 Hydra CPU
  • 2 Fastnet 20/20 Displays
  • 1 Analog Apparent Wind Display
  • 2 Hydra Fastnet/NMEA 0183 Race Displays
  • ActiSense NGW-1 (0183 to N2k)
  • Robertson AP22 Autopilot & Compass
  • B&G Halcyon Compass
  • AirMar 800 Depth Sensor


  • B&G H5000 Hercules CPU
  • B&G H5000 Pilot
  • 2 Garmin GNX 120 7” Displays
  • B&G Triton Display
  • B&G H5000 Display
  • B&G ZG100 GPS
  • AirMar 810 Speed/Depth Sensor
  • B&G N2k Rudder Position Sensor

We retained our existing Zues3 MFD, 4g Radar, autopilot ram, Precision 9 compass, Bluetooth AP remote control, AirMar speed paddle wheel, and MHU wind sensor. We also kept the NAC-3, a second P9 compass, and hydraulic ram offline as redundant spares.

Installing the New Instruments

This would be a fairly big install. Although the displays are similar in size to the old ones, they were not exact and would require some cutting and minor fiberglass work. The existing rats nest behind the navigation station would be cleaned up in the process, but most of the old wires are all run through headliners and hard to get at. This required some minor disassembly.

The good news is, you can use B&Gs Fastnet wires and put N2k ends on them. This is a huge time and effort saver. Our friends at Twig Marine have the connectors on hand for special orders. Keep in mind that standard N2k wires may not fit through the old Fastnet conduits due to the size of the N2k end connectors.

Dealing with the J Boats Hood

The instruments in the standard J Boats style companionway hood were the only tricky part to deal with because of NMEA 2000s backbone and drop standards. Yes, one can pigtail a few instruments off of one drop cable even though it doesn’t meet the official standard. We could have just used a drop into the hood, but these are our primary visual steering aids, and our GPS would be there as well.

We couldn’t afford any electrical hiccups here, so we decided to change the backbone to end in the hood, rather than in the nav station. This gives the benefit of a more centrally located power source but makes the backbone longer and more risk of voltage drop. Fortunately, our total backbone length is well within the standards.

We mounted our GPS in the hood for two reasons. First, we just didn’t like any of the locations available at the back of the boat for hole drilling. Second, and most importantly, the view of the sky is sometimes obscured on the transom by solar panels, dinghy, liferaft, etc. Lastly, we felt the closer the ZG100 was to the boat’s center of axis, the better.

We placed the Triton display where the old analog apparent wind gauge was, right in the center. We liked the apparent wind in this position and wanted to replicate it with the Sailsteer feature.

Garmin and B&G Together?

One may have already noticed that we chose to use two Garmin displays in this system in the place of B&G 20/20s. There are several reasons. First, they are cheaper, saving us about 400 dollars over the 20s. Second, they are very readable, have big digits, and can display two lines of data each, doubling the possible readouts in this location. Third, unlike the B&Gs, which only read their own PGNs in the N2k network, the Garmins will read anything.


The holes required for the GNX 120s were much smaller than the 20/20s, so we decided to fill them with StarBoard material (a hard plastic like material which won’t take on water). The only problem was there was none available at the local chandleries. Luckily our friends aboard Sailing Sargo had some extra to spare and hooked us up so we could finish the project.

We can fire our Expedition Navigation Software PGNs from our computer, through the ActiSense NGT-1 to the GNX 120s to view any other data we want. We use our polars and Expedition software religiously for weather routing, so this is important to us.

Once we had the hood back together, we decided to retain the location of our existing Hydra race display near the main sheet winch. This is in a prime racing location for the driver, main trimmer, and tactician. It also gives a great view of lots of data from them helm.

We would have likely forgone this location for cruising, but filling this hole was easier, cheaper, and better looking than re-glassing and re-painting or putting a blank in.

Installing the CPU and Autopilot

Now that we had all of the new displays in place, it was time to untangle the macrame that was the Nav station wiring. This is pretty standard on an old boat that has received numerous upgrades and changes over time. It has been on our to-do list for a while.

We ripped everything out all of the old stuff and got to work making sense of the old wiring. We mounted the H5000 CPU and Raymarine AIS unit to the wall, along with securely mounting all N2k connectors. Now, it is far from the perfect glamorous wiring job, but we can quickly diagnose and fix any potential problems.


Outputs for the ActiSense and CPU both run out below to the nav table for connection to the laptop and Expedition Software. The H5 computer itself was an easy hookup, as it could utilize the existing H2 connections for power, wind, and speed. Other than that all that was required was connecting the NMEA 2000 wires, easy.

The H5 Pilot Computer was an easy plugin replacement in place of the NAC-3, which now resides next door in case of emergency. Installing the new RPS (rudder position sensor) was a breeze as it is the same size as the old analog version. We kept the analog version as it still works with the NAC-3 as another layer of redundancy.

Installing the Speed/Depth Sensor

The last thing we needed was to install our NMEA 2000 compatible depth sensor. H5 can’t use the old style, but fortunately, AirMar likes to make customers’ lives easy and the new 810 unit fits easily in place of the old depth sensor. They even give you the needed o-rings to fit the older thru-hulls. As a bonus, the new sensor has Bluetooth configuration and outputs additional data such as a redundant source for heel and pitch.


Once everything was connected and in place, we fired the system up for its final checks. Everything seemed to be working pretty well and initial calibrations were close (close enough for fair weather recreational cruising).

Calibrating the H5000 System

We did our dock calibrations but waited a few days to go sailing. Our next sail would be to an island about 50 miles south, but the weather window required us to leave the harbor in the dark. We did the at sea autopilot initializations and speedo calibrations under the moonlight, but we had smooth water, light winds, and little current, making calibration easier.

Sailing with the B&G, Expedition and Garmin Hybrid

We still have some advanced calibration and fine-tuning to do. We can report though, with just basic efforts that the system performed without a glitch, and Jeeves (our name for the autopilot) drove with a steady hand and laser focus!

We were sailing in 4-7 knots of breeze in a decent-sized leftover but well-spaced swell. We were using a #3 cruising headsail and cruising Dacron main, easily maintaining speeds in the 90% polar range. The H5 can certainly drive better than the other autos we have tried and will likely save us its cost in fuel over the long run.

We still have some more detailed tuning to do and heavy air testing, but we are pretty happy with the outcome so far. We are also looking at integrating a few more on-boat systems into the NMEA 2000 network in the future such as our engine and fuel data, fridge and freezer temps, and tankage levels.

We hope to revisit this and give more feedback as we put more miles on with this configuration.

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