Using the compass or not?

[Otter-BelleHavenMarina]

I agree with the belt-and-suspenders approach to navigation, but in answer to one of Cavu's questions: yes, modern GPS chartplotters take bearings every second and you can steer straight by their course. Was surprised to hear Blue-C's use of a magnetic mount for his compass -- doesn't the magnet affect the reading? Put my portable speakers on the dash too close to the compass one time and magnets threw it way off.

(Although I have a lousy sense of direction, I seem to always be able to find my way to the nearest pub!)

[B~C]

Iza just funnin you....had a friend that got messed up out in the fog off the mouth of the Columbia because he had a portable radio by his compass and didn't realize the impact it had on his compass

[CAVU]

Tom, I have a Furuno unit without mapping capability, but I thought they all worked the same. I believe they require the boat make some headway for a certain distance before they can compute which direction you are going? I usually experience several days of fog during my summer fishing trips and have found that it is not easy to steer a straight line in the fog. When I have tried to use the compass display on my GPS I find I am constantly "chasing" the arrow. You have to maintain a fairly constant heading to give the machine a chance to compute a direction. My real world experience with my GPS tells me this is very difficult without a compass to monitor my heading. I am not saying it can't be done, but without the compass I would make a much longer more crooked track.

[Anita Marie]

I think I will always have a compass after reading this.
GPS shutdown

[TyBoo]

[rogerbum]

[Larry H]

Roger,

The GPS will still point you to the waypoint with a course and distance even if you are not moving. So if you set a waypoint near the bouy or light, you will know how far away and in what direction it lies and you can use a magnetic compass to determine direction until the boat is moving again.

[dogon dory]

Sorry, Folks - Post Deleted By Author

[Not For Hire]

I like Dan's post. Points out that some may leave shore without a compass (at least a mounted one) but then he relates a number of good reasons why he personally relies on that compass. I boat all over the Great Lakes in my 19 foot boat. I have two permanently mounted compasses in the boat. (3 1/2 inch direct read card at the helm and another 2 inch front read compass mounted on the dash where I can see it from the back of the cockpit when fishing and someone else is steering). I also have a mounted GPS and an extra handheld GPS and my pocket PC has GPS as well. My keychain has a compass and so does my tackle box. Guess I am easily confused, but I like to know what direction I am headed before I put it in gear, real foggy or unfamiliar waters at night, etc.

I was in the Coast Guard Auxilliary for a number of years and taught classes on navigation and compass. I have swung ship on my own boats and have done it in an amateurish way on other boats as well. I run a string from bow to exact midpoint on stern. Then I run another string parallel to that one through center of wheel, helm seat and compass. Used to run marked courses to swing ship but now use GPS.

A couple of other hints (borrowed from Chapmans or other books or experienced boaters over the years). When you buy a compass check it on the store counter. I don't care if it is off a couple of degrees as that can be adjusted. I bring my pocket knife or some other metal close to the compass and see how far it deflects and how fast it settles. Then remove the knife and see how fast it returns and how quickly it settles. You will see a variation in same compass from same manufacturers. Most compasses also have an opening to add fluid. Sometimes air bubbles will develop in a compass (although the better ones with rubber diaphrams seldom exhbit this) particularly if the boat is stored outside in Midwest winters for instance. The fluid is merely mineral oil. It make take a couple of times to open the screw hole, add oil, replace screw and check to see if all air is out, but it can be done.

I say 1. paper charts, 2. compass, 3. GPS on list of navigation essentials. The extent to which you can use and rely on the GPS-Chatplotter, etc., to replace the chart and compass depends on the quality and reliability of your GPS and your skill in using it. But keep at least a small scale paper chart and a $3.00 compass on board as well.

[Bearh]

Amen to the sentiment behind "Don't leave home without it" and beyond that, do what you need to know how to use it if you need it. GPS is good, but fallible in oh so many ways. Together with a compass, mighty good. Together with someone who knows how to use both well, mighty, mighty good.

[Larry H]

I too like Dan's summary.

A postscript to the above comments;

A cruise ship hit rocks off the East Coast of the USA because the GPS antenna wire was damaged and the auto pilot couldn't tell that the GPS location had not updated.

Navigation occurs in the mind of the navigator. Be sure your mind is engaged and alert to the changing conditions.

[Captains Cat]

Just a compass related tale.

We've got a second home in DownEast Maine, about 70 miles from the Canadian Border on Little Kennebec Bay. Great spot on the lower Bay of Fundy, 17 feet of tide, when it goes out, it goes waaaaaaay out . Lots of lobstering, scalloping, etc. Many friends with lobster boats, etc. A good friends son wanted a GPS and didn't know how to mount/use it so I negotiated a deal with him to trade cost for "lobster futures". At $2.75 a pound , it was a good deal. He had a 34ft DownEast Hull Lobster boat with a Cat Diesel, nice stable boat. When I got there to install the GPS, he asked me if I knew anything about compasses .

What's to know, I thought. Only one moving part, no power unless they have illumination. Seems he'd been navigating without one because he couldn't get it to behave correctly, always pointed SE no matter what direction he was going . Amazing that he was even alive given the fog conditions on the coast of Maine and that he'd been fishing for a couple of years, sometimes single handed.

Anyway, I got down there to mount the GPS and noted the compass (pointing to SE, just as he said) just forward of the helm on the stbd side. I also noted some black boxes on either side of the compass. When I enquired as to the function of the black boxes, he turned on the stereo and showed me that they were speakers.

I moved them over to the port side of the boat and the compass immediately swung over to NE which is where it should have been pointing. "Dagnabbit" he said (or words to that effect), why'd it do that? I explained about magnetism and how a magnetic compass worked. Finally got through.

Installed the GPS, trained him for a couple of hours, (retrained him each summer since too) and he was a happy camper .

Sally and I were too, the GPS cost me $350 which bought me 100# plus in lobsters over the next couple of years. Couldn't bring myself to charge him anything for installation or training. He's now a competent navigator, can come in and out during fog without endangering his life. His Mom and Dad were happy too!

A compass is important! Understand how it works and how to use it!!!!

[hardee]

I have been looking for compass, magnetic, the will mount overhead, and read from the side closest to the helm seat. Wondering if anybody has any recommendations for a good compass that will fit that application? I am wanting to install a backup to my fluxgate electronic compass.

Harvey
SleepyC

[ppriest]

I concluded, after a couple of disconcerting episodes, that it was well worth the time to sit down and figure out the sources of all the various types of information displayed on my chart plotter AND how it is that I might detect failure of any of those sources. The Raymarine system actually reports some of those (ex., Loss of Heading, etc.) although it's not always obvious what the true source is. More important, still, is having the means to determine the significance of that loss and, if necessary, to be able to substitute some other source.
I now routinely set the electronic (flux-gate) compass to display increments of deviation from the selected compass heading at every change of course heading even though the plotter is set to display compass heading and cross-track error. I use the e-compass for maintaining (and corrrecting) heading and the chart display for current position and potential conflict (radar) information.
The GPS-derived heading info on the chart plotter responds too slowly to be of much use for holding a heading especially at low speeds.
And I have a magnetic compass mounted close to line-of-sight behind the e-compass as a secondary reference when visibility outside becomes questionable.
So far, so good; until someone offers a better scheme.

Paul Priest
J.C.Lately
Sequim, WA

[Sea Wolf]