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Monday, February 7, 2011

How Do You Swing?

Did you know that a compass is affected by ferrous metal placed near it?  I notice that when I'm using my hand held compass to get the correct direction for my portable satellite dish, if I get too close to the tripod, the little needle points towards the tripod instead of North.

On a boat, a compass is very important, because, for some strange reason, there are no traffic signs in the ocean.  To navigate properly, you need a good compass.  On our Coast Guard boats, there is a good compass located on the dash, right in front of the helm, for the helmsman (helmswoman?) to steer a course by.

However, a boat is loaded with all kinds of ferrous metal, the engines, reduction gears, framework, etc, that can throw the compass off.  So to correct that you have to "Swing" the compass. 

Basically, you have to set out on a known course, looking at a nautical chart and place little magnets around the compass until you get its needle to match the direction on the chart.  A few circles around in the water to confirm you have swung the compass accurately and then the magnets are locked down.  Until such time as an engine is changed, or the compass is removed for maintenance, then you have to do it all over again.

Probably by now, you are wondering where the heck I'm "heading" with this (pun intended)?

Our Journey does not have a compass.  Even though most modern cars and trucks (and our last motorhome) have installed compasses, for some reason that technology was left off, probably by the Winnebago Bean Counters.  I want it install a compass that is reasonably accurate and adjustable.  I don't mind spending money, but so far the compasses I've looked at don't have a way to calibrate (or swing) them to get line up with the Northern direction.  And there is a lot of ferrous metal in our Journey.

I'd hate to be tooling down  what I think is a west heading highway only to see the sun set off my left shoulder as my left ear gets sunburned.

We intend to install solar panels on the Journey roof for those times we anticipate boondocking in the wild Western deserts.  I'd like to be able to look at a compass on my dash and see which way is East so I can park with the solar panels pointing South to get the most energy from the sun

Now that you know what I'm talking about, a question:  If you've purchased an aftermarket compass for your RV, what did you buy and do you recommend it?  I'd appreciate your input so I don't get lost wandering around in the desert with my little cheapo handheld compass.

Thanks for visiting and feel free to leave a comment.


  1. This post really interests me. I, also, have a Winnebago without a compass. I didn't know it was called swing, but I do know I have to back off away from the DISH when setting it up to get a truer reading.

    I hope you'll post the results of your inquiries into what compass is best. :)

  2. no compass in our horizons as yet..sun rises in the east and sets in the west..that is pretty much all I know!..our condo faces northwest!..go to the water..west..other water..long way...east!..warmer south..colder north!..thats it for my swing!!
    can't wait to read the results!!

  3. The GPS I use has a north pointing arrow on it so as I near our final location I pay attention to that more than usual so that my panels can get the most effective sun.

  4. My Meridian came with a built in compass that shows quarter points. I otherwise rely on the GPS for true headings.

    If you want a compass, you could use a flux gate compass which is less affected by its surroundings. I have one of these that I use only rarely, but is quite reliable.

  5. Yup.. .we wanted a compass for the same reason as you do... solar aiming.

    Although our Streets and Trips program has a compass on it, it would mean we would *have* to have the laptop on just to use it.

    So I found Steveio a cute computerized digital compass that runs on batteries and is stuck down to our dash with double stick tape. Works Great... about $35 at a camping supply store. About the size of a deck of cards, with a flip up lighted display screen.

    Karen and Steve
    (Our Blog) RVing: Small House... BIG Backyard

  6. Sorry, don't have a recommendation but we also wanted a compass in our Class C Lazy Daze. We tried one and it turns out there is too much magnetic interference under the hood so it wouldn't read accurately. If you have a diesel pusher with a rear engine this shouldn't be a problem.

  7. You should look at trying to get one off an old ship, if you can. Would be kinda cool to bring a piece of you past with you on your new journey.

  8. Love Kevin and Sheryl's idea for you.

    But I hope you'll get some good answers that I might be able to use for the same reason and with the same concerns.

    I know you'll let us know how you solve the problem Thanks in Advance!


  9. I bought a compass at the dollar store, but the suction cup doesn't stick well. I'll play with it more later -- maybe use tape. My handheld gps has a built in magnetic compass that can be calibrated. (Garmin GPSmap 60csx.)