Siting a fluxgate compass

[Pendle Witch]

I am seeking some information/advice concerning the siting of my fluxgate compass. My boat is steel hulled so the optimum site below decks is not an option. I am reluctant to site it up the mast as I do not relish the idea of adding yet another cable to be withdrawn from the boat if the mast is unstepped and the cable routing in my case would be a nightmare.
I have a stainless gantry over the cockpit and I am considering siting it here and minimising the movement by constructing a stainless weighted gimble mounting.
Any advise or information would be most welcome.

 

[MontyMariner]

minimising the movement by constructing a stainless weighted gimble mounting.

I thought fluxgate compasses were gimbaled 'out of the box'
A picture of your proposed site would help.

 

[rogerthebodger]

I am seeking some information/advice concerning the siting of my fluxgate compass. My boat is steel hulled so the optimum site below decks is not an option. I am reluctant to site it up the mast as I do not relish the idea of adding yet another cable to be withdrawn from the boat if the mast is unstepped and the cable routing in my case would be a nightmare.
I have a stainless gantry over the cockpit and I am considering siting it here and minimising the movement by constructing a stainless weighted gimble mounting.
Any advise or information would be most welcome.

I also have a steel boat with a fluxgate compas.

My fluxgate compas is mounted under the stainless-steel gantry and works file my fluxgate feeds my autopilot, and my autopilot keeps the course very well.

I just followed the calibration instructions that came with the autopilot / compas.

The compas is internal gimbled and mine is just mounted under the gantry without only other gimbling mounting

 

[Ian_Edwards]

I had a similar problem.
The Southerly has a 4ton cast steel plate recessed into the hull, and a 2.5 ton cast steel centre board.
The ballast plate extends from well towards of the mast to just forward of the 2.2L diesel lump.
After a lot of trial and error, I mounted it between the head lining and the deck. About midships and 2m above the ballast plate and steel centre board.
So a couple of meters above the steel work, seems to do the trick. It's worked like that for the last 12 years.

 

[Graham_Wright]

The siting arrangements are a near-impossible equation to solve.
Centre of roll and away from magnetic influence. I'm lucky as my mast support pillar is stainless.
If you have Raymarine, there is an evolution to minimise deviation automatically. Maybe steel hulled boat chases its magnetic signature dynamically?

 

[Pendle Witch]

I thought fluxgate compasses were gimbaled 'out of the box'
A picture of your proposed site would help.

My theory is based upon the recommendation to mount centrally on the boat to minimise movement. Perhaps the internal gimballing is somewhat limited and placing it anywhere other than centrally will exceed the limits of this provision?? Certainly at the stern the movement could be considerable in heavier weather, hence the suggestion.
I have constructed a weighted gimbal and mounting plate and will report back on my findings hopefully later this year. Thanks for the advice.

 

[rogerthebodger]

I have had no issues with my flux gate compass mounter in my stern gantry at the stern and it even steered my boat over an 80 nm cruse in quite bumpy passage

 

[MontyMariner]

I have had no issues with my flux gate compass mounter in my stern gantry at the stern and it even steered my boat over an 80 nm cruse in quite bumpy passage

Same here, I mounted mine on the centre line under the aft cabin bunk, no issues when it's a bit uperty.

 

[rogerthebodger]

Same here, I mounted mine on the centre line under the aft cabin bunk, no issues when it's a bit uperty.

My boat is steel so compass location is important, so I mounted it under a stainless-steel solar arch as far from any magnetic metals as possible