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To integrate or not to integrate?

Sep 27, 2006

No I don't mean schools - I mean navigation instruments. In particular, whether we should let our GPS units talk to (and direct) our auto-pilots.

Used to be that the "third rail" of boating conversation (touch it and you die!) was the topic of which anchor was best. But lately it seems that the topic my friends and I disagree about the most is the question of whether to let our GPS units direct our auto-pilots. For me this is a no-brainer, with the answer being yes. But I am amazed at the number of folks with sophisticated electronics aboard who feel this is downright unseamanlike.

When I am doing a single-handed overnight delivery I set my GPS unit up with a route containing a series of way points of my desired track. And since I am going to be using the auto-pilot to steer the boat, and depending on the GPS for position data, it seems perfectly reasonable to me to go one step further and let the GPS direct the auto-pilot by steering to minimize the cross track error rather than to a fixed compass heading.

My standard routine is to check the on-deck read out of cross track error every 5 minutes or so, and go below every 30 minutes to plot my position on the paper chart and check the agreement between the two GPS units and the LORAN. The auto-pilot beeps and requires me to acknowledge any course change when a way point is reached, so there is no question of the boat changing heading without my input.

But while this seems like the natural order of things to me, the majority of my friends do not use their gear this way. They insist on having their auto-pilots steer to the compass heading suggested by the GPS, and then correct as necessary to keep the cross track error to a minimum. Which seems silly to me. If you are going to rely on the GPS unit for position data, and the auto-pilot for steering, why not let them do it?

So how do you do things aboard your boat? Am I off base here, conducting myself in an unseamanlike fashion? Or are my friends closet Luddites who enjoy the magic of GPS but can't quite bring themselves to trust it?

Alex Agnew on 09/28/2006 14:00

Hi Steve: I personally feel more comfortable deriving my heading directly from a paper chart (using mechancial tools) and then setting a course based on that. It keeps my head in the game better. I feel like I am navigating rather than being navigated. The electronic chart on the laptop and the plotter are both running most of the time now, with radar usually, but there's less chance of getting confused and disoriented if I know that I have ordered a course based on a single original source--the paper chart--and kept track of time and distance right on the chart. I do trust the electronics and really love the radar chart overlay and I do skip the paper from time to time but I guess you can call me a Luddite as I don't think that using GPS waypoints to drive the autopilot is something I'm now ready to bet my life on.

peter stoops on 09/28/2006 20:24

i agree with your reasoning about using the gear, but there is definitely an intrinsic emotional issue as well. in other words, there's no denying the logic: if you are using/trusting ANY electronics, you mights well use/trust 'em all! if you can push the button for an electronic fix, or push the button to engage the autopilot, hell - you oughta be able to push 'em both at once, right? but, as alex says, it depends on what you are willing to trust - an emotional reaction, not necessarily a scientific one. myself, i have to admit that i don't like using a chart plotter in the fog - but i'm not above using a radar! my reasoning is that i believe that the bouy i see on the radar is accurate - it's really where it is - but i do not trust my position relative to it when i see it on the plotter. go figure... i think it's a personal thing. no doubt it could be cured with prolonged psychotherapy sessions!

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