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Old 09-16-2016, 02:06 PM   #1
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Magnetic vs Electronic Compass

If you have added an electronic compass such as the KVH Azimuth, have you removed your trusty magnetic compass ie. the big one at the helm or have you added the electronic compass but left the magnetic compass in place?
-David
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Old 09-16-2016, 02:39 PM   #2
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I installed the KVH Azimuth at my PH helm because there was too much interference for the mechanical to work. I left a matching mechanical compass (my terminology is probably wrong, but I believe both the KVH and what I am calling mechanical are magnetic, its just that the KVH relies on a remote flux gate sensor) on the flybridge. Both also display a satellite compass (Furuno SC-50), which I accept as perfectly accurate. The KVH is much more accurate than the mechanical.
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Old 09-16-2016, 02:41 PM   #3
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Took off the magnetic compass and replaced with KVH Azimuth. Had them in multiple boats, never had a failure and there isn't a place to mount two compasses.
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Old 09-16-2016, 03:03 PM   #4
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I left a matching mechanical compass (my terminology is probably wrong, but I believe both the KVH and what I am calling mechanical are magnetic.
The slang term that drives the point home is "whiskey compass".

Flux gate compasses are easier to read and can be displayed any way a manufacturer wants...as well as being able to provide NMEA data. Conventional compasses(whiskey compass) have errors and can sometimes be confusing to read. I rarely even look at my compass. I would if I needed to but have all the direction sensing instruments that I need without it.
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Old 09-16-2016, 03:23 PM   #5
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I would never be without a robust whisky compass. When everything else fails it still works.
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Old 09-16-2016, 04:05 PM   #6
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Originally Posted by petdoc4u View Post
If you have added an electronic compass such as the KVH Azimuth, have you removed your trusty magnetic compass
-David
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Originally Posted by bayview View Post
I would never be without a robust whisky compass. When everything else fails it still works.
If you already have one why remove it???
I have both and like the back-up and logic check...
recently noticed the flux gate was being affected by a tool box stored under the galley steps by comparing it's output to others...moved the tool box
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Old 09-16-2016, 04:10 PM   #7
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A swung, properly located (just like a fluxgate requires) and compensated whiskey compass will have few errors and they can be listed on a card. I found mine handy for taking quick bearings on oncoming vessels, though I mostly used my Fujinons for that. My auto pilot and radar/plotter each had their own fluxgate/heading sensors as well. The only non-magnetic compasses I know of are the satellite variety.
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Old 09-16-2016, 04:32 PM   #8
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A swung, properly located (just like a fluxgate requires) and compensated whiskey compass will have few errors and the can be listed on a card. I found mine handy for taking quick bearings on oncoming vessels, though I mostly used my Fujinons for that. My auto pilot and radar/plotter each had their own fluxgate/heading sensors as well. The only non-magnetic compasses I know of are the satellite variety.
Satellite compass? Never heard of such a thing. Besides, a compass is pretty much a waste anymore. Just use one of your GPSs..... way better info and more accurate.
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Old 09-16-2016, 04:39 PM   #9
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A swung, properly located (just like a fluxgate requires) and compensated whiskey compass will have few errors and the can be listed on a card. I found mine handy for taking quick bearings on oncoming vessels, though I mostly used my Fujinons for that. My auto pilot and radar/plotter each had their own fluxgate/heading sensors as well. The only non-magnetic compasses I know of are the satellite variety.
I was talking about this stuff!!! And there are more than in this article. They are errors endemic to the compass.

Application of Error to a Compass
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Old 09-16-2016, 04:45 PM   #10
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Satellite compass? Never heard of such a thing. Besides, a compass is pretty much a waste anymore. Just use one of your GPSs..... way better info and more accurate.
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Old 09-16-2016, 05:02 PM   #11
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While I still have mag compasses and can actually use and swing one...not sure I have used one in my last 20,000 nautical miles or so.

Last time I steered on one was maybe 1993.

I can see the advantages of something like the KVH....but I wouldn't toss my $500 mag at the helm for one...because I probably wouldn't use it much either.

Everyone has their likes and dislikes...also the cash to add things that are sexier than their predessesor.

Are they critical for primary or backup nav? Only you can decide....
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Old 09-16-2016, 05:05 PM   #12
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Satellite compass? Never heard of such a thing. Besides, a compass is pretty much a waste anymore. Just use one of your GPSs..... way better info and more accurate.
Actually not in some cases.

Slow speed in reduced vis, the gps ability to give you smooth turn info isn't able to.

You have to turn on a compass or radar in con fines waters....gps turn info just lags too much at very slow speeds.

And every once in awhile, your gps may be very erratic for some odd reason...visit the Navy warship thread....
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Old 09-16-2016, 05:25 PM   #13
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Does the KVH Azmuth perform better than a rate compass like a Simrad RC42, Maretron SSC200, or Furuno PG700? The Azmuth would appear to be a rate compass just like the others, except with an integral display.

I really like sat compasses. They are super accurate, provide both GPS and heading data, don't require calibration, doesn't get messed up when you rearrange stuff on the boat, doesn't go nuts when you turn on high power appliances, and give true heading which is required for certain nav devices. The Vector V104 (sold by Simrad, SeaPilot, SiTex, and a variety of others) costs about the same $$ as a good GPS + rate compass.
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Old 09-16-2016, 06:54 PM   #14
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GPS plotter tells you what direction you've traveled from, not where you are pointed to. Bang-head indeed!
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Old 09-16-2016, 07:21 PM   #15
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Satellite compass? Never heard of such a thing. Besides, a compass is pretty much a waste anymore. Just use one of your GPSs..... way better info and more accurate.
Obviously never you have never been in a situation where your electronics failed.
GPS goes down, flux gate compasses go down.

A properly compensated (with deviation card) magnetic compass will always get you home
How much experience do you have?
Compass a waste? You have not been far enough and long enough on board to know!
Had a KVH compass and loved it till it went out and had to make a 120nm run on a hand held Bering compass.
Not bashing electronics here I rely on them 99.9% of the time, but just remember a properly installed magnetic compass will always work when everything else goes down
Bone up on your manual navigation skills, if you ever travel further than sight of land you may need them
Good luck and cheers!
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Old 09-16-2016, 07:25 PM   #16
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GPS plotter tells you what direction you've traveled from, not where you are pointed to. Bang-head indeed!
If, by "GPS plotter", you mean "chart plotter", it does tell you the direction you are headed if it is getting heading information from a GPS-based sat compass.
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Old 09-16-2016, 08:03 PM   #17
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Obviously never you have never been in a situation where your electronics failed.
GPS goes down, flux gate compasses go down.

A properly compensated (with deviation card) magnetic compass will always get you home
How much experience do you have?
Compass a waste? You have not been far enough and long enough on board to know!
Had a KVH compass and loved it till it went out and had to make a 120nm run on a hand held Bering compass.
Not bashing electronics here I rely on them 99.9% of the time, but just remember a properly installed magnetic compass will always work when everything else goes down
Bone up on your manual navigation skills, if you ever travel further than sight of land you may need them
Good luck and cheers!
Panacea,

We may agree to disagree, but in this day and age a compass is pretty much worthless, unless one needs heading info for other devices like radar, etc.

Years ago, it was a necessity... that's ancient.

I've been boating and flying for over 45 years, and have had the best and the minimal amount of equipment. Before loran and GPS one needed heading and a chart where they plotted a course and boated that course using a compass, and it worked fine. And, yes, I've had numerous failures of equipment and a few total failures and back then the compass was the life saver.

Today with GPS it's dirt simple. We only need to know where we want to go, and the TRACK that is required to get us there. Heading is not necessary at all. Now, if you only have one GPS on board, perhaps you will want a good old paper chart and a compass, and that's fine, if you wish, but I'd bet the majority of us have 2, 3 or 4 gps systems on board, and some are battery powered so if you totally loose ships power (and you have to have a MAJOR problem with that... usually with three batteries and a genset), then use your back up GPS to get you home.

Since Loran and GPS has been out, I have not needed a compass at all (but still required in some situations), and even with a total failure getting home has not been an issue.

I have no problem if one want a fancy compass, just not for me.
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Old 09-16-2016, 08:12 PM   #18
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Actually not in some cases.

Slow speed in reduced vis, the gps ability to give you smooth turn info isn't able to.

You have to turn on a compass or radar in con fines waters....gps turn info just lags too much at very slow speeds.

And every once in awhile, your gps may be very erratic for some odd reason...visit the Navy warship thread....
Psneeld,

Do you really need a compass to turn you boat? (we're talking recreational boats not ocean liners). True, the GPS can lag, but a good one lags very little and the gps positioning on the chart plotter is pretty accurate.

And, yes, GPS gives track HISTORY, but it does give the track that one needs to make good to get home.

As for the "satellite compass", the satellite is for the GPS portion, you don't get compass or heading info from a satellite... it just ain't there. While these are neat gadgets, do we really need them? The heading info, is still a basic compass, and sure it can be dampened and coupled with gyros to give a lot of info, like tilt and accurate heading. Just don't need it.... at least for navigation.
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Old 09-16-2016, 08:15 PM   #19
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If you have added an electronic compass such as the KVH Azimuth, have you removed your trusty magnetic compass ie. the big one at the helm or have you added the electronic compass but left the magnetic compass in place?
-David
I have had two KVH Azimuth 1000 compasses on my last two boats. Both replaced the "whiskey Compasses" and were mounted in exactly the same places as the old compasses. They are more accurate , self calibrating & you can see your deviation from your desired course at a quick glance. They also use the old 12v compass wiring. Simplest thing i ever added to my boat and one of the most useful!

On my existing boat, I'm going the same route as soon as the pain of previous additions wears off!
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Old 09-16-2016, 08:29 PM   #20
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If, by "GPS plotter", you mean "chart plotter", it does tell you the direction you are headed if it is getting heading information from a GPS-based sat compass.
MYTraveler,

Just for clarification, the vast majority of chart plotters have NO heading information in them at all. They show position, track made good (history) and desired track to get where you're going (if you set up a route). Some have other fancy features that are handy, but for heading, one needs a compass which can be a fancy remote one with a flux gate and be pretty accurate but for HEADING, not track. And heading is magnetic, not true. We rarely need true, but it's probably a thought to understand the difference, especially if one lives in California. Here in FL and the midwest the difference is minimal. (variation).

Track is the thing that gets us where we are going, not heading. Now, FWIW, they are identical if there's no current, wind or tide, which is not likely.
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