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Old 12-20-2010, 11:46 AM   #1
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Use of a compass

In the thread about instrument panel layouts someone mentioned that these days a magnetic compass is almost irrelevant and not to give it much consideration when designing a panel or helm console layout.* So I thought it might be interesting for people to post their own ideas regarding the value of a magnetic compass.

In our waters, where the current seems to change every hundred yards, we find ourselves using the magnetic compass almost constantly.* We have two large GPS plotters at the helm station, one of them a plotter only and the other a Furuno NavNet (radar and plotter).* Both plotters have what in aviation are called "noodles" or the dotted lines that extend forward of the boat's position indicator and tell you were you will be in a predetermined time that you can adjust.* We have the noodles on both our plotters set for ten minutes, as I recall.* (You can also set them to show a specific distance.)

We removed the autopilot from our boat when we bought it and so steer by hand.* We have both found it is a lot easier to hold a heading using the magnetic compass than by chasing the plotters around.* We use the plotters or their steering displays to confirm that the heading we are holding with the compass is still accurate and hasn't been changed by the current.* But trying to hold a heading using the plotters alone requires an almost constant reference to the plotters because of the frequent and sometimes rather radical current changes we encounter on virtually every leg of a trip.* The heading and bearing readouts on the plotters are digital so you have to read the numbers to see what's changed, and the noodles, while "analog" and so don't require any "reading" to decipher, don't make small heading changes readily apparent immediately (this depends on the scale the plotter is set to, of course).

Our magnetic compass, on the other hand, is easy to read at a glance and it makes heading changes, even very tiny ones, immediately and obviously apparent.* Plus the compass is mounted in a place the helmsman is looking anyway, so there is no need to look to the side, look down, or look up at a plotter display all the time.

Eric mentioned not liking an overhead position for a plotter, and I don't disagree with him.* However, the plotter function of the Furuno (like most if not all modern plotters) has a very user-friendly steering display.* It's somewhat in the form of a graphic compass but includes heading and bearing information as well as a simple graphic showing where the boat is in relation to the course line and which way to steer to get back to the course line.* We usually split the Furuno screen to have the radar display in the top half and the steering display in the lower half.* (The older, green-screen Echotec plotter we leave in chart display all the time.)* So it's just a matter of a quick glance up--- it doesn't even require any head movement--- to confirm that the compass heading we are holding is the correct one for the current we're in.* But the compass is our primary steering tool as far as holding a specific heading is concerned.

Based on this experience, were we designing a panel or helm station layout for a new boat, we would make sure the magnetic compass was a good one, large enough to be very easily readable, and mounted in a position where it was in or nearly in the helmsman's normal line of sight when looking forward.

That's for these waters.* Were we boating in something like the ICW, which from the photos I've seen is essentially a ditch, a magnetic compass would perhaps have little value with regards to steering the boat.*

I don't know how useful a magnetic compass would be for open water/ocean cruisers today.* While I've done a lot of ocean fishing in Hawaii, we were never out of sight of land even when we were twenty or thirty miles out and so simply used the island on the horizon as our reference point.* Of course the boat had a compass, but this was in the days before GPS and we didn't have a Loran so the compass was it with regards to navigation equipment.* But I don't recall us every actually referring to it.




-- Edited by Marin on Monday 20th of December 2010 01:22:24 PM
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Old 12-20-2010, 12:05 PM   #2
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Use of a compass

Quote:
Marin wrote:

In the thread about instrument panel layouts someone mentioned that these days a magnetic compass is almost irrelevant and not to give it much consideration when designing a panel or helm console layout.* So I thought it might be interesting for people to post their own ideas regarding the value of a magnetic compass.
It seems we both may be a little different than others regarding compass use.* My magnetic compass is just a little above my navigation display screens.* There is a compass deviation chart to the left of the helm.* Because there are things that can throw off the readings from* from either the electronic or magnetic compass, I use one to check the other.* Of course metal objects can affect magnetic readings.* I once had something stored in the forward bilge that got against the electronic compass wiring. It pulled it to the point that it was barely making contact and giving false readings* I discovered this by comparing the two compasses.

When on the ICW there is a magenta line on the preferred course.* The line is labled with headings.* When lining up with the course I use the magnetic compass.* I learned the old way with parallel rules, dividers, compass*and paper charts.* My get home when offshore*was an RDF tuned to an AM radio stations.* We still run with paper charts along with our electronic charts.* A belt and suspenders approach I guess, but I just feel better that way.

I have a hand bearing compass on board for taking bearings, but I would not want to try to steer a course by it for any distance.* I like my magnetic compass just where it is.* That is just below my line of sight.

*


-- Edited by Moonstruck on Monday 20th of December 2010 01:09:23 PM
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Old 12-20-2010, 01:28 PM   #3
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RE: Use of a compass

We almost always use the auto pilot when boating in the PNW. But --- this past*spring when crossing Dixon Entrance there was a large and confused*following sea (5 - 7 feet) and 25 to 35 knot gusts, rain and fog.

These conditions made it very difficult for the AP to maintain a safe heading and for me to get visual references. I elected to hand steer using instruments. The NN3 has a very easily seen true and magnetic "box" display*which for me was a lot easier to hand steer by than the magnetic compass as the boat moved around. Combined with the NN3s radar, maintaining a hand steered course was quite easy. I used the magnetic compass only for reference.*

As the summer progressed, digital radar and solid state compass readouts were often the hand piloting method of choice when conditions turned nasty. On my Nobeltec, when I scale down, the highway reading shows an immediate departure from course - but not quick enough to hand steer by when a big following sea is running.

The most ambitious cruiser of our time is Steve Dashew. Pull up his setsail website and look at the Windhorse helm area. One thing missing for sure*from his Windhorse is a wheel. Try to find a magnetic compass.
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Old 12-20-2010, 02:26 PM   #4
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RE: Use of a compass

When running with the autopilot but not on a route, I like to use the compass to eyeball my new heading and then tap the port or starboard key to bring the AP up to the new heading.

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Old 12-20-2010, 02:51 PM   #5
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RE: Use of a compass

At anchor, *the compass, with just a quick glance is an easy way to see which way the wind is blowing.* It's also*a mechanical check against all the electronics.

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Old 12-20-2010, 02:54 PM   #6
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RE: Use of a compass

My lower helm compass (brass and black, flat top, classic appearance) is hidden from view as it is in a domed, lighted enclosure and is electrically connected to the old Wagner S50 AP. So for steering I use the "bearing" and "course" readouts on the Capn screen. Keep them close, allow the same + and - deviations, and steering a good compass course is as easy as watching the compass swing from above and below your course.
Up top, the Ritchie compass is a little easier to see, but now that I am in the habit, the GPS readout still works the best for me.
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Old 12-20-2010, 03:14 PM   #7
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RE: Use of a compass

If you live where there is a million people and cell phone access.
Who needs a compass.

If you get into trouble call boat US or whoever.

Electronics fail.

If you get down to all you can count on is the motor and a non electric basic technology.
i.e. A compass and paper charts.

If you tossed the compass what do you do then.

Keep the compass or stay where you know everyone and everything.

SD
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Old 12-20-2010, 03:46 PM   #8
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RE: Use of a compass

Good comments all.

As one of those who is suggesting that I would not have the compass front and centre, I would like to be clear that I am NOT advocating it's removal, just that it no longer have the central location that it once had. There was a time when I would not venture out of a harbour without the compass right there in front of me, but nowadays I find that electronic charts and all of the info they provide - SOG, COG, etc., provide ongoing confirmation that I'm on track. Most of my situational awareness is provided via looking outside at landmarks etc. (I cruise the west coast of BC so am seldom if ever out of sight of land.)
I also always have the paper charts out and in use; the plotter is complementary to but not a substitute for them.
Although the romantic in me would love to have a big brass compass at the helm I think the reality is that a smaller one close at hand would still provide me with the same ability to navigate when required. And if it is not fixed, i.e., *hand bearing, I can use it at any time anywhere on the boat to determine swing at anchor etc.
Of course if it falls overboard then my arguments lose badly....
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Old 12-20-2010, 03:58 PM   #9
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Use of a compass

We have both traditional compasses (2) and GPS chartplotters (2). As well as radar. We are constantly comparing them to each other for anomolies as we run a course, while also keeping track all the while on paper charts and of time run, even though we may no longer be keeping a "proper" dead reckonong plot as we used to do. Like others here, we grew up before "even" Loran when RDFs were the latest word. Yes, indeed, electronics fail according to Murphy's Law principals.

One of the things I liked about Loran was that you were constantly exercising one aspect of chart skills by taking off a Lat/Long from the chart to plug into the Loran, or vice versa. Real rusty on that now. And they say that the US GPS satellite system is in danger of gradually going down due to aging satellites for which there is no funding to replace. Oh well, the Russkies are going to put up a GPS system of their own that we can use, just like the Ukrainians can use the Russkie oil pipelines.

I'll keep our antiquated, liguid filled, traditional compasses front and center til they tear them out of our cold, dead hands (er, dashboards) thank you.


-- Edited by dwhatty on Monday 20th of December 2010 05:28:31 PM
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Old 12-20-2010, 03:59 PM   #10
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RE: Use of a compass

Quote:
skipperdude wrote:

If you tossed the compass what do you do then.

If I were that far offshore that I needed a compass to return to land I would:

Magnetize a sewing needle and stick it in a piece of cork*then float it in a bowl.

Break out the handheld GPS.

Look at the sun and a clock.

Open the SOLAS A pack liferaft and take the compass out of it.

Break out the sextant and the instruction book and reduction tables.

If I were inshore I would just use pilotage and navigate from point to point on the chart.
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Old 12-20-2010, 04:09 PM   #11
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RE: Use of a compass

"As one of those who is suggesting that I would not have the compass front and centre, I would like to be clear that I am NOT advocating it's removal, just that it no longer have the central location that it once had"

That's about my feeling too. I use it to "guess" a turn with the autopilot as mentioned above, I use it at anchor, and only casually when underway to stay semi skilled in it's use so I don't end up in France when I head to Block Island.
Of course I hear France is nice in the summer....
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Old 12-20-2010, 04:13 PM   #12
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RE: Use of a compass

Right on RickB.

Perfect idea and solution.

I think people get complacent and have been living in the city to long.
You have to think on your feet in an emergency situation.

Sometimes you just can't rely on the techno gods to save you.

SD
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Old 12-20-2010, 04:54 PM   #13
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Use of a compass

Quote:
RickB wrote:

*
skipperdude wrote:

If you tossed the compass what do you do then.
If I were that far offshore that I needed a compass to return to land I would:

Magnetize a sewing needle and stick it in a piece of cork*then float it in a bowl.

Break out the handheld GPS.

Look at the sun and a clock.

Open the SOLAS A pack liferaft and take the compass out of it.

Break out the sextant and the instruction book and reduction tables.

If I were inshore I would just use pilotage and navigate from point to point on the chart.
Why don't we go ahead and move this discussion to OTDE?

*


-- Edited by Moonstruck on Monday 20th of December 2010 05:57:01 PM
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Old 12-20-2010, 05:25 PM   #14
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RE: Use of a compass

Hiya,
** Mr. Moonstruck.* I don't think this has drifted THAT much off course to move it to OTDE (yet).** Nobody has yet mentioned their Dick Tracey wrist radio, Captain Midnight decoder badge or Bat phones.* All good information thus far.
** Personaly, I LIKE my compass front and center and I DO use it occasionally albeit for short periods of time (course corrections etc.)
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Old 12-20-2010, 05:30 PM   #15
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RE: Use of a compass

Quote:
jleonard wrote:... so I don't end up in France when I head to Block Island.
Hey, it worked for Doug Corrigan!
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Old 12-20-2010, 05:47 PM   #16
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RE: Use of a compass

Quote:
RT Firefly wrote:

*Nobody has yet mentioned their Dick Tracey wrist radio, Captain Midnight decoder badge or Bat phones.*
OK, RTF.* Now we are getting back on track.

*
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Old 12-20-2010, 09:37 PM   #17
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RE: Use of a compass

Quote:
Marin wrote:


In our waters, where the current seems to change every hundred yards, we find ourselves using the magnetic compass almost constantly.

*

I agree that changing currents requires constant to the course made good but that can be done by referring to a plotter/GPS course line. I do find having the AP *not coupled to plotter is a good way to keep my attention on things outside that change like currents, vessel traffic *and logs.

*

*

*
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Old 12-21-2010, 08:44 AM   #18
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RE: Use of a compass

Lower and upper helm pics from a year ago when I installed new Garmin electronics. The "Captain's" hat is on top of the Ritchie compass at lower helm. Not shown at the upper helm is the remote mic for the VHF (stowed away).

If I had the dash room at the lower helm, my preference would be for a stand alone radar in addition to the MFD. Had that on the last boat.
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Old 12-21-2010, 09:31 AM   #19
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RE: Use of a compass

dwhatty- I was wondering if you were aware your boat appears to be on dry land (from the GPS display), but then I saw the plastic wrap in the bridge shot!

Dave
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Old 12-21-2010, 11:53 AM   #20
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RE: Use of a compass

Quote:
magicbus wrote:

dwhatty- I was wondering if you were aware your boat appears to be on dry land (from the GPS display), but then I saw the plastic wrap in the bridge shot!

Dave
We were a little off course that day and just decided to wrap her for the winter where she ended up. Saved a bit on the travel lift bill.

*
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