Join Date: Nov 2009
Thanked 47 Times in 46 Posts
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I switched from a wheel pilot to a below deck autopilot about 10 years ago and couldn't be happier. The old Autohelm (Raymarine ancestor) was very unreliable on my 13,000# 35 footer. Our below deck Raymarine (formerly Raytheon) autopilot uses an electrical drive unit and is coupled to my chartplotter.
I just replaced all of my electronics (due to a lightning strike) in 2010 with Raymarine gear because the Raytheon stuff worked well and was ultra-reliable.
With just 2 of us, the autopilot has become a third crew member, making the longer trips more relaxing for us. Because it is integrated with the chartplotter, it accommodates set and drift and adjusts the boat's heading to stay on the rhumb line to a waypoint.
By the way, we can enter waypoints directly from the chartplotter instead of picking them off a paper chart and using a calculator to figure out decimal minutes. The 2010 chartplotter allows us to control the autopilot directly, so there is no confusion in setting a waypoint.
Regarding the accuracy of charts, we just returned from the Virgin Islands and carried a portable Garmin chartplotter with the current Eastern Caribbean chart chip. It was rather impressive for its accuracy in reef areas--where it really matters--at least where we were able to verify.
That said, the chartplotters use mapping data from a third party that obtains data from sources that may not be up-to-date. In many cases the mapping data is derived from paper charts that were published before GPS-based mapping was available, so you need to stay alert in unfamiliar waters.
We have also seen mapping errors in local waters that showed up on both Raytheon and Garmin charts, which obviously used the same source for mapping data. BTW, that particular problem was fixed a long time ago. The message here is that the accuracy of electronic charts is probably the same, no matter whose chartplotter you buy. If you buy a chartplotter that uses chips, make sure you have the latest chips. (You should also have recent paper charts, as a hedge on electronic failure.)
Bottom line: We consider an autopilot integrated with a chartplotter to be indispensable for shorthanded cruising. It is a safety feature should one of us be injured underway. Primarily, it is a great convenience that makes for a more relaxing cruise. The helmsperson can eat a sandwich with both hands, for example, and can concentrate on watch duties while the autopilot manages set and drift (if it is coupled to a chartplotter) and otherwise handles the tedium of maintaining your course.