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Electronics

Automatic Autopilot

John Redmond of Redmond Marine Electronics in Destin, Florida, does some pre-assembly in Betty Jane’s saloon.

Hand-steering my 1988 Grand Banks 32 Betty Jane for hundreds of miles down the eastern seaboard some years back qualifies me for a profound appreciation of autopilots. Certainly, the trip was physically onerous, considering the lower-back pain spinning spokes all day engenders. But there was mental stuff, too. Try referencing a chart book sometime while simultaneously keeping tabs on a plotter, bird-dogging the road ahead, and steering a reasonable course and see if you don’t lose a marble or two.

But experience is a great teacher. Which is why not long after Betty and I got home to Florida I resolved to add an autopilot, specifically one from Simrad, which was then developing a new model I was hearing good things about. Eventually, a gratifying scenario arose: Simrad would provide me with a new AP28 pilot if I’d pay for its installation—including any adaptations necessary to blend Betty’s old-school, cable-type steering system with NMEA 2000 technology—and write a story covering not only the installation but also the unit’s long-term performance.

When the AP28 arrived, I appreciatively noted that there were just a few basic parts: the control head, the RC42 rate-technology-enhanced fluxgate compass, the AC42 Course Computer, the drive unit (more about this later), the RF300 rudder-feedback device, and an assembly of cables and connectors. What I didn’t understand, however, was that laying out and securing this componentry is typically not the biggest challenge for installers. Often, the real biggie is getting everything to work with a particular steering system.

To recap, Betty’s steering system is a manual sprocket-and-chain arrangement that moves her rudder via long, pulley-supported cables. After checking it out, John Redmond of Redmond Marine Electronics in Destin, Florida, figured the best way to translate electronic signals from the new ‘pilot into mechanical rudder movement was to put an extra sprocket on the steering-wheel shaft inside Betty’s upper steering console (the lower one is comparatively cramped) and then install a powerful, (and expensive) clutch-equipped Lewmar electric motor with a sprocket of its own directly beneath, the two sprockets being joined by a loop of stainless steel roller chain.

Other approaches wouldn’t work, explained Redmond. Betty’s rudder quadrant was structurally incompatible with the sort of quadrant-connected linear-drive that Simrad had shipped. And because her steering system is not hydraulic, it would also be impossible to tee into a ram with a hydraulic pump, a method Redmond said was simplest and cheapest of all.

I began the installation by securing a custom-made, marine-ply mounting block for the Lewmar motor inside the flying bridge cowling with screws and 3M 5200. I then removed the steering shaft from the same area and took it to a machine shop to add the sprocket. Then I assembled the motor and everything else into a cowling-covered, workable whole. This part of the project took a grueling 30 hours and cost roughly $1,470, a figure that excludes labor (since I did most of the work myself) and the aforementioned motor, which might have cost $3,000 had Simrad not come across with a second-hand freebie.

Redmond’s part of the project went faster and, at $1,750, was less expensive. Once I’d finished with the mechanicals, he returned to Betty to install and interconnect the control head, rate-technology-enhanced fluxgate, Course Computer, and rudder-feedback device, completing the project in just over half a day. Such speediness was partially due to the easy way Simrad’s Slim Line connectors and pre-measured cables go together, a true time and trouble saver. But another reason was Redmond’s bag of install tricks: for instance, he used a pocket compass to quickly find a relatively deviation-free spot for mounting the AP28’s fluxgate.

My performance evaluation began dockside. Well before I cranked up Betty’s engine for an actual sea trial, Redmond and I had programmed her displacement characteristics and some other static parameters into the control head. We’d also successfully set maximum rudder travel and tested the feedback device. The whole deal took 30 minutes.

Another major time and trouble-saver announced itself once we hit open water: Simrad’s new auto-tune feature. Instead of having to spend hours tweaking individual dynamic steering parameters as we used to have to, Redmond simply let our Course Computer take command and put her through a series of S-turns, registering and setting said parameters en route. Amazingly, the portion of the sea trial that involved the auto tune, vetted most of the AP28’s navigation features, and interfaced the unit with my Garmin GPSMAP 3206 plotter, took a little over a half a day, including run time from my marina and back. “An automatic autopilot,” I chortled, upon realizing that my new AP28 was virtually sea trialing itself.

This article originally appeared in the May 2009 issue of Power & Motoryacht magazine.

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