Location of J/42 Fluxgate Compass in Bow

[Albert Bossar]

Hi all

We are in the midst of a complete electronics upgrade and I have a question.

Where have others located the fluxgate compass? Are all/most in the bow as well?

My existing compass is located in the bow. Wondering if this is ideal or located there out of necessity.

I can’t find a place aft that would not present interference from metals.

Thanks
B

[Gary Hooper]

Bert,

I have mine installed in the bottom of the forward locker against the bulkhead...works fine there.

Gary

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From: j4x-owne...@googlegroups.com <j4x-owne...@googlegroups.com> on behalf of Albert Bossar <abo...@gmail.com>
Sent: Wednesday, March 13, 2024 9:15 AM
To: j4x-owne...@googlegroups.com <j4x-owne...@googlegroups.com>
Subject: [J/4X-owners] Location of J/42 Fluxgate Compass in Bow

 

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[Tom Keffer]

I wanted to avoid putting my Precision-9 in a locker because it seems like someone is always putting something metal close to it. So, I settled on under the forward berth, on the bulkhead of the head. 

[Todd Stevens]

Lots of places for the Precision 9 (Unlike some others) because you can rotate it in its mount.  Former location was behind the stbd settee, on the bulkhead. New location, bottom of hanging locker, fwd bulkhead.  No matter where it goes, it seems there’s a constant battle to keep metal away.  I reserved the behind settee locker for bulk foodstuffs no cans.  

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[David Shapiro]

Ours is mounted on the forward side of the bulkhead separating the nav station and the starboard settee, between the water tank and the bulkhead, down low, away from most of the metal.

David Shapiro

SV "Sandpiper"  J42 Hull # 32

To view this discussion on the web visit https://groups.google.com/d/msgid/j4x-owners-group/0A64F190-5524-4865-A615-59D4C37151B6%40me.com.

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Bridger Aviation Services, Inc.

P.O. Box 1029

Three Forks,  MT  59752
406-579-3166

[Fred Hawes]

I installed mine on the aft side of the aft bulkhead, in my J46. Access thru the bench behind the wheel. Has worked well several years.

Fred Hawes

Anona, J46 #16

[gale...@gmail.com]

I installed my B&G Precision-9 Compass outside on the aft bulkhead of the forward cabin hanging locker just below the main cabin stb settee and forward of the water tank. Picture shows airmar N2K connection only. Compass N2K attached to the backbone here at T connector. This spot is totally out of the way and secure from any shifting items. Unit performed well and suspect no metal interference. Sorry no photo showing mounted compass. Easy and protected.

Galen

J42 Tango

[Tom Keffer]

Galen, I was very tempted by that spot, but it looked like it would be an adventure working around the tank, so I reluctantly gave up the idea. Glad to hear that it worked out for you!

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[Albert Bossar]

Thanks Everyone !  

This install has been nerve racking. We are trying to pull it all together. We thought we were selling then we weren’t !  

Now we are upgrading electronics and sailing in both A2B and N2B!  

On Mar 13, 2024, at 8:39 PM, Tom Keffer <tke...@gmail.com> wrote:



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[Albert Bossar]

Thanks all much appreciated! 

Sent from my iPhone

On Mar 13, 2024, at 8:39 PM, Tom Keffer <tke...@gmail.com> wrote:



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[Steven Novak]

I’ve used a SCX-20 as my primary compass for the past 2 seasons, and absolutely love it.  No mounting location issues, no guests stowing metal or a speaker someplace unexpected, and better accuracy than the fluxgate it replaced, at least in real world use.  Worth every penny.  

An added bonus is the combination of the 6 axis movement detection with the GPS allows it to compensate for roll and yaw of the boat and output a “stabilized” COG and SOG that isn’t impacted by the waves.

And yes, before anyone asks, it provides a true heading (direction the boat is pointed), not just a COG, and works at rest.

-Steve

J/37 “Monomoit”

On Fri, Mar 15, 2024 at 5:36 PM Chris Campbell <camp...@ramoak.com> wrote:

Have you considered the Furuno SCX-20 GPS compass instead? Isn't bothered by location of metals, and from what I can gather is actually more accurate. I'm going to try one out in the next couple of years, likely beside the existing Precision-9 at first.

My Precision-9 is currently located behind and beneath the port-side settee on a J/44 (under the middle drawer).

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[Jay PA]

Warning:  My J/42 came with a B&G fluxgate compass "mounted on the forward side of the bulkhead separating the nav station and the starboard settee, between the water tank and the bulkhead, down low, away from most of the metal".  (David's spot.) After 4 seasons of sailing this boat, I just noticed a 15 degree autopilot course change when I removed or stored a flashlight from the bottom drawer under the nav table.  Duhhh!  That nice deep handy drawer, loaded with lights and batteries is 4 inches from the fluxgate. I have tool bags behind the starboard settee back cushions.  I'll move ithe compass to the "aft bulkhead of the forward cabin hanging locker just below the main cabin stb settee and forward of the water tank" (Galen's spot) and move toolbags elsewhere.  Live and (re)learn.

Practically speaking, I almost never care about the compass course value or even the deviation, as I steer to match COG to Bearing-toWaypoint along the leg of a route, or to hold whatever the course is.  But seeing the deflection of my wake in the glass calm water surely was a visible realization that a changing deviation can be dangerous.  Be careful.  And don't forget to put the flashlight back where you found it.

Jay P-A

J/42 Cirrus

[Michael Moradzadeh]

Love it!

On my prior boat, the compass was installed near the nav station but under a storage area.  A large "NO METAL HERE" note failed to impress the crew, so I later moved the compass to an area under the floorboards somewhat forward where I had not seen toolboxes placed.

It's nice to have the compass and any heel sensors near the center of the boat where motion is minimized, but the no moving iron part comes first.

Michael

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[Joseph Ruzzi]

When my cousin first bought his boat and tried cruising with her, he was having huge problems with his fluxgate compass reading waaaay off, at seemingly random directions.  After quite a bit of digging, it turned out that the drawer just above the location of the compass, was the perfect place for him to store a magnetic parts tray.  Basically, his compass was trying to point straight up!   Once he moved the tray to another location, his chart plotter problem went away.  ;-)

Joe 

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[Todd Stevens]

Yeah, I had a little problem a couple of months ago, after returning to the boat with a new day pack.  Set off from La Paz under sail and the chart plotter showed us going sideways down the channel!  Couldn’t use the autopilot until I could get clear of shoals and traffic. (About an hour.) But I discovered that backpack has a strong little magnet in the strap to hold the drinking tube from the water bladder.  D’Oh!

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[douglas wilder]

Joe

regarding the flux gate compass.  I ran into an issue after years of no troubles.  When storing my stuff to begin living a board I place my medication box in the cabinet just forward of the hanging locker (j46).  I found that moving the plastic container and meds the 90 degree variation disappeared.  Makes me wonder what in the heart medication…

Get Outlook for iOS

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From: j4x-owne...@googlegroups.com <j4x-owne...@googlegroups.com> on behalf of Joseph Ruzzi <jmru...@gmail.com>
Sent: Friday, May 30, 2025 10:51:25 AM
To: j4x-owne...@googlegroups.com <j4x-owne...@googlegroups.com>
Subject: Re: [J/4X-owners] Location of J/42 Fluxgate Compass in Bow

 

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[Michael Moradzadeh]

My best one was someone (not me) installed the heavy power lines for the autopilot draped right over the compass.

Every time the autopilot initiated a turn, the compass went haywire!

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