Chart plotter interferes with compass?

[chachere]

The instructions for the chartplotter I just purchased (Garmin 740s) state that it should be mounted at least 32" from a compass. I was planning to put in on the Edson pedestal guard at the wheel, which is right above the compass, as I've seen on many other boats. Even with a higher pedestal guard, there's no way to get it 32" away without putting the thing overhead!
How real is this interference concern? I see so many boats with clusters of electronics by the compass at the pedestal....

Matthew
Catalina 36 "¡Que Chévere!"

[Yorksailor]

I once chartered a boat where the radar swung the compass 30 deg.

I think the pedestal is the wrong place to mount the plotter. We use the autopilot 95% of the time on long passages and we stand/sit watch tucked in under the dodger out of the rain so that is where we have the plotter.

Being right handed we sit to port and the plotter is to starboard. We can still see the plotter when we are at the helm.

Also when the plotter is at the helm having it in your face blinds you at night

Every crew member for the last 3 yrs has queried the plotter placement until they stood their night watch in the rain. Or helmed the boat into a difficult entry at night.

My wife and I are a team so on any difficult entry one of us cons the boat watching plotter, charts and aids-to-navigation while the other concentrates on steering.

Phil

[svHyLyte]

Originally Posted by chachere

The instructions for the chartplotter I just purchased (Garmin 740s) state that it should be mounted at least 32" from a compass. I was planning to put in on the Edson pedestal guard at the wheel, which is right above the compass, as I've seen on many other boats. Even with a higher pedestal guard, there's no way to get it 32" away without putting the thing overhead!
How real is this interference concern? I see so many boats with clusters of electronics by the compass at the pedestal....

Matthew
Catalina 36 "¡Que Chévere!"

The problem is the magnetic closure system for the card slots. The magnet is strong enough to have an adverse effect on the compass. You can observe that by simply holding the plotter near the compass. The cure, discussed in several other threads is to remove the magnet and hold the slot cover in place with a band of tape (some have used silicon but that does make opening the slot cover a bit of a problem). The draw-back to this "fix" is that by opening the case to access the magnet, you void the warranty on the device. In theory one could degauss the magnet without opening the case but there is no telling how that might effect other components. It is for this reason that I have not yet replaced our old G-162 tho' I would certainly like to do so. Very frustrating.

FWIW...

[FishSticks]

Had the same problem with the Garmin 546. I opened it up and removed the magnet. Taped the door closed and it's been fine since. Check this
http://www.sailnet.com/forums/electr...s-compass.html

[olson34]

Originally Posted by chachere

The instructions for the chartplotter I just purchased (Garmin 740s) state that it should be mounted at least 32" from a compass. I was planning to put in on the Edson pedestal guard at the wheel, which is right above the compass, as I've seen on many other boats. Even with a higher pedestal guard, there's no way to get it 32" away without putting the thing overhead!
How real is this interference concern? I see so many boats with clusters of electronics by the compass at the pedestal....
Matthew
Catalina 36 "¡Que Chévere!"

Matthew, The best solution for this this example of extreme arrogance by Garmin would be to simply buy a chartplotter from another company that actually builds one for sail boaters. Since you just purchased yours at least you can get your money back. Check out a Furuno or Raymarine.

Garmin provides but buries the compass interference information many pages deep into their install manual in the hope of defending against a wrongful death lawsuit from your surviving relatives after your boat is wrecked on a jetty or reef some dark night. ( Any halfway good lawyer would simple show the jury their full page ads in sailing magazines and blow right through that defense. )

At least you read the instructions!

L

[chachere]

Originally Posted by olson34

Matthew, The best solution for this this example of extreme arrogance by Garmin would be to simply buy a chartplotter from another company that actually builds one for sail boaters. Since you just purchased yours at least you can get your money back. Check out a Furuno or Raymarine.

Garmin provides but buries the compass interference information many pages deep into their install manual in the hope of defending against a wrongful death lawsuit from your surviving relatives after your boat is wrecked on a jetty or reef some dark night. ( Any halfway good lawyer would simple show the jury their full page ads in sailing magazines and blow right through that defense. )

At least you read the instructions!

L

Olson - Its probably in part due to my occupational disability (I AM a lawyer) that I compulsive read through the entire installation manual BEFORE I actually starting to install this thing (at which point it would have been hard to return to WM - I don't think I could sue WM, even though their salesperson -- who claimed to be an experienced sailor -- assured me this would work out just fine mounted at the pedestal guard.)

Originally Posted by FishSticks

Had the same problem with the Garmin 546. I opened it up and removed the magnet. Taped the door closed and it's been fine since. Check this
http://www.sailnet.com/forums/electr...s-compass.html

Fishticks -
I did find your earlier posts on this subject. Thanks. However, as has been pointed out, that will end the warranty on a unit that's only a week old. So not really a good solution.
I'm going to take the display unit over to the boat today and see whether and how much the door magnet swings the compass (with the unit unpowered, since I'm not going to start wiring this if its probably being returned). But its most likely that I'll be paying a visit to WM to demand a refund (oddly enough, I attempted to write a customer review raising this issue on their website, but curiously WM seems to have declined to publish it on the product review....), and start saving up pesos for the Raymarine C90.

Thanks all for the feedback and help.

[svHyLyte]

Originally Posted by chachere

Olson - Its probably in part due to my occupational disability (I AM a lawyer).

We will forgive you for that.

N'any case, if it is any consolation, we know of several cases where the touch screen systems failed in relatively short order with cockpit installations. They seem to be oriented for interior helmstations.

While they have now been discontinued, I understand that the 3206c and 3210c are the last of the series without the magnetic locking system that have most all of the features of the unit you have but with a keypad. The units are still available at reasonably good discounts and Garmin will still make repairs if they need it. I am looking at one of these as an alternative for our 162 although I'd prefer a unit with the same shape factor as the 162 so I don't have to modify our installation or wiring.

FWIW...

[chachere]

Originally Posted by svHyLyte

We will forgive you for that.
.

I appreciate your understanding (although these days public school teachers seem to be the new public enemy in some eyes).
I've been checking into the 3206 and 3210 as a result of others' recommendations as alternatives (I think Mainesailor, among others, made this suggestion on another thread), and they can indeed still be found for a good price. The 3206 screen looks somewhat challengingly small for those of us with older eyes, and while the 3210 might do, the other downside I've read is the older technology -- apparently the 3200 series uses a proprietary card made by Garmin for updating software and charts (as opposed to the newer ones that use SD cards), and the fear is that Garmin will drop support and the cards sooner than later. If I'm going to buy something new, it doesn't seem to make sense to get something that may be orphaned very soon... (yes, I know, that IS the general business model these days).

At this point I'm vacillating between picking up a used JRC 1000 (if I'm going to go with older tech) for a few hundred bucks for now or just holding off and getting a Raymarine C90 (if I'm going to drop some serious money on this project). We cruise in the NE, and really just looking for something simple that can give us an idea if something moving out there is coming in our direction if we find ourselves fogged in (which happened to us a few times last summer, and was more than a little scary).

[svHyLyte]

Originally Posted by chachere

I appreciate your understanding (although these days public school teachers seem to be the new public enemy in some eyes).
I've been checking into the 3206 and 3210 as a result of others' recommendations as alternatives (I think Mainesailor, among others, made this suggestion on another thread), and they can indeed still be found for a good price. The 3206 screen looks somewhat challengingly small for those of us with older eyes, and while the 3210 might do, the other downside I've read is the older technology -- apparently the 3200 series uses a proprietary card made by Garmin for updating software and charts (as opposed to the newer ones that use SD cards), and the fear is that Garmin will drop support and the cards sooner than later. If I'm going to buy something new, it doesn't seem to make sense to get something that may be orphaned very soon... (yes, I know, that IS the general business model these days).

At this point I'm vacillating between picking up a used JRC 1000 (if I'm going to go with older tech) for a few hundred bucks for now or just holding off and getting a Raymarine C90 (if I'm going to drop some serious money on this project). We cruise in the NE, and really just looking for something simple that can give us an idea if something moving out there is coming in our direction if we find ourselves fogged in (which happened to us a few times last summer, and was more than a little scary).

For what it's worth, we have the 2006c at our nav-table and a couple of spare chips which are not hard to come by. So long as one has the computer interface connected one can easily up-date charts and software from one's laptop without difficulty. I'm in my mid 60's and also developing challanged vision but the 2006c's screen is very legible. The 10 is better but takes up too much real estate. Unfortunately, Garmin and many of the other electronics vendors replace their lines at roughly 2-3 year intervals and only support discontinued units for a few years after that. Our units are both 9 years old at this point and repairs are no longer offered. I understand the same is true of Raynav instruments and some of the others.

N'any case, good luck with your efforts. I know the process can be very frustrating...

s/v HyLyte

[chachere]

Thanks -- yet again -- for the feedback and advice. These sorts of info sharing fora among actual users are so much more useful in many instances than the breathless hype we get from manufacturers' and retailers' sites.... (and, apparently, the censoring of less than gushing user's "reviews" on at least one major marine retailer's website).