Here is the second page of our Garmin GHP10 review. This page covers our slow speed operational testing as well as navigating to waypoints and along routes with this advanced autopilot.
If you haven’t already read it part one of this Garmin autopilot review is here.
Slow Speed Operation
Seveal weeks later, at the request of a reader, we did some additional slow speed testing with the Garmin GHP10. Normally our Contender idles along at about 3.5 knots, at this speed the autopilot held heading rock steady in the calm test conditions.
Next we added some drag with by throwing several 5-gallon buckets that were tied to transom into the water. This slowed us to about 1.9 knots, still the autopilot held steady on course.
Finally, we went into a channel with a bit of current, kept the buckets deployed, and trimmed the engine up several degrees?all this got the GPS speed down to 1.0 knot. Still the autopilot held the heading steady under the relatively calm conditions.
So far we have been pretty impressed with Garmin GHP10 capabilities. We?ll try this slow speed handling again soon in some rougher conditions and report back.
To navigate to a waypoint or along a route requires the GHP10 be able to receive information from a GPS unit. We decided to hook up to the Garmin 5212 we have on our test boat via a NMEA 2000 network.
Once the wiring was complete we tried to couple the autopilot to the GPS, however we were unable to do so initially because the software in our 5212 needed to be updated from version 2.5 to the latest version 4.6.
Garmin sent us a card, which once inserted, allowed us to accomplish the software update in under 10 minutes. With the GPS units updated, and after turning everything off then back on again, the GPS and autopilot were talking.
We could now see the appropriate menu selections on the GHC10 autopilot control head to navigate using GPS input.
To test things out we first setup a waypoint about a mile away and engaged the Garmin GHP10 in the GPS steering mode.
This requires selecting the menu, then choosing GPS steering, and finally choosing to navigate to a waypoint. Not really the easiest procedure for engagement.
Hopefully in a future software update Garmin will add a GPS softkey on the front page and enable one-button navigation.
Once engaged in GPS steering mode the autopilot tracked a course to the waypoint. We noticed that as we ran the boat drifted off-course up to several hundred feet. The off-course distance was indicated both on the 5212 display and on the GHC10 controller.
As the boat approached within several hundred feet of the waypoint position the autopilot would turn toward the waypoint ending up passing within 10 feet of the coordinates. This happened on several passes.
Garmin suggested we redo the north setting (part of the Garmin GHP10 setup procedure) since when it was originally accomplished the GPS unit and autopilot were not communicating. We will do this soon and report back here on the results.
The Fix is In
After more consultation with Garmin representatives it was determined that the autopilot software needed another update. With the navigation system using software version 4.6 and the autopilot using version 2.2 the 5212 would report a cross-track error to the right while the autopilot reported the same amount of error except to the left. This caused the navigational issues we noted.
Now with the autopilot running the latest software available, version 2.4, all the navigation issues with staying on course have been solved. We tried running routes with multiple turns, changing speeds, and starting out pointed in the opposite direction; nothing seemed to phase the system. Right now things are running smoothly with rock solid course tracking.
Long Haul Review
We just returned from a 620 nautical mile round trip to the Bahamas and had to report on the outstanding performance of the Garmin GHP10 autopilot. We had the unit on and following a track or route for most of the trip and found it held the boat right on course even in heavy chop and big following seas. Our crew was impressed and very happy they didn’t have to steer manually for hours a day.
What Does the Future Hold?
The only navigational issue we could see now with the Garmin GHP10 was when following a route. Youll find the pilot will pass the turn point before it starts to track to the next waypoint. This allows some cross-track error to develop after the turn.
The Garmin folks hinted that future software updates will have more advanced algorithms that will allow the autopilot to start a turn in a route before the vessel arrives at the turn point and more closely follow the track line. We look forward to trying this one.
You’ll also need a pump, three are available, so make sure you get the one sized for your steering system and horsepower.
Shop for the Garmin 2-Liter pump kit here. The 2-liter pump kit is for most standard installations with hydraulic steering systems under 10 cubic inches.
You can find the Garmin 2.1-Liter high performance pump kit here. The 2.1-liter pump kit is for larger capacity rams sized greater than 10 cubic inches and outboard applications of two or more motors with combined total horse power greater than 400hp. This includes both Verado and non-Verado applications.
One remaining pump option is the Garmin 1.2-Liter pump kit. The 1.2-liter pump kit will fit most Verado installations up to two outboards or less with under 400 combined total horsepower.