Klaus
New Member
Anybody on this forum having experience with mounting a fluxgate sensor inside a steel hull? I don't like the idea of mast mounting because of the excess movement.
Klaus
Klaus
Steel hull and fluxgate sensors?
- Thread starter Klaus
- Start date
gerry99
Well-Known Member
Hi Klaus, if you think about it, the steel will form a type of faraday cage and in itself will magnetise and therefore I am not even sure if it would work if fitted inside the hull.
I suggest you chat to the vendor to get their professional view. I have sailed on a 65ft steel yacht where we had two mast fitted sensors, one on the main and the other on the mizzen, we never had any problems with excessive movement affecting accuracy, including trips to the med and across the atlantic.
Cheers
I suggest you chat to the vendor to get their professional view. I have sailed on a 65ft steel yacht where we had two mast fitted sensors, one on the main and the other on the mizzen, we never had any problems with excessive movement affecting accuracy, including trips to the med and across the atlantic.
Cheers
hightech
Well-Known Member
Fluxgate compasses will not work inside or in close proximity to a steel hull or superstructure. Industry advice is to mount any fluxgate compass a minimum of 1 metre (3 feet) away from anything with a significant magnetic component and in the case of a hull 2 metres would be more preferable.
Whilst mounting a compass up the mast might seem to attract movement errors, the software engineers are well aware of this possibility and will have written their code to minimise this.
I have installed on and have sailed on many steel boats with compass both mounted up masts, on poles and also on a radar/solar panel arch. These have then been used as both main steering compass and also as autopilot sensors with no ill affect.
Watch out for poor stainless steel as well, much of the production materials used on boats that puports to be stainless will have a significant magnetic component. Always test any proposed fluxgate mounting area with a hand bearing compass, if you get less than 1-2 degrees of error than the location is likely to be satisfactory (magnetically). Take specific care in mounting in areas where items are not in their stowed position, like anchors, outboards, gas bottles etc, have the boat in a sea-ready condition when siting.
Whilst mounting a compass up the mast might seem to attract movement errors, the software engineers are well aware of this possibility and will have written their code to minimise this.
I have installed on and have sailed on many steel boats with compass both mounted up masts, on poles and also on a radar/solar panel arch. These have then been used as both main steering compass and also as autopilot sensors with no ill affect.
Watch out for poor stainless steel as well, much of the production materials used on boats that puports to be stainless will have a significant magnetic component. Always test any proposed fluxgate mounting area with a hand bearing compass, if you get less than 1-2 degrees of error than the location is likely to be satisfactory (magnetically). Take specific care in mounting in areas where items are not in their stowed position, like anchors, outboards, gas bottles etc, have the boat in a sea-ready condition when siting.
Klaus
New Member
OK, thanks for your replies. I'll try the mast then and se how it works out.... /forums/images/graemlins/smile.gif
ianabc
Well-Known Member
There are a number of post at the Metal Boat Society forum.
One post describes fitting a flux gate sensor inside a steel hull, close to the center of gravity, with success!
Perhaps try googling Metal Boat Society.
You do not need to be a member to search and read the posts.
One post describes fitting a flux gate sensor inside a steel hull, close to the center of gravity, with success!
Perhaps try googling Metal Boat Society.
You do not need to be a member to search and read the posts.
Ships_Cat
Well-Known Member
Our fluxgate is mounted around 4m up the mast (so about 5m above the waterline) and we have experienced no problems with it, even in some quite boisterous seas with a lot of rapid motion.
Fluxgates will often work inside a steel hull (our handheld fluxgate compass is surprisingly accurate inside the hull) but it is something that I would avoid as I would regard it as unreliable.
John
Fluxgates will often work inside a steel hull (our handheld fluxgate compass is surprisingly accurate inside the hull) but it is something that I would avoid as I would regard it as unreliable.
John
Birdseye
Well-Known Member
[ QUOTE ]
Anybody on this forum having experience with mounting a fluxgate sensor inside a steel hull? I don't like the idea of mast mounting because of the excess movement.
Klaus
[/ QUOTE ]
Basic Physics. Cant be done. It has to be outside the steel hull. Preferably as far away as poss.
Anybody on this forum having experience with mounting a fluxgate sensor inside a steel hull? I don't like the idea of mast mounting because of the excess movement.
Klaus
[/ QUOTE ]
Basic Physics. Cant be done. It has to be outside the steel hull. Preferably as far away as poss.
jerryat
Well-Known Member
Hi Klaus,
If I remember correctly (will check next time I'm on boat) the installation instructions for my VDO360 fluxgate compass suggests, with reference to steel hulled boats, that the sensor should be installed up to 15 feet (about four and a half metres) up the mast to avoid the problems mentioned here. Setting the response time to 'Low', would help reduce/eliminate any pendulum effect from this location.
I'll post again if the actual instructions (guess all sensors would require similar consideration) are different when I've been to the boat in the next day or so.
Cheers Jerry
If I remember correctly (will check next time I'm on boat) the installation instructions for my VDO360 fluxgate compass suggests, with reference to steel hulled boats, that the sensor should be installed up to 15 feet (about four and a half metres) up the mast to avoid the problems mentioned here. Setting the response time to 'Low', would help reduce/eliminate any pendulum effect from this location.
I'll post again if the actual instructions (guess all sensors would require similar consideration) are different when I've been to the boat in the next day or so.
Cheers Jerry
Ships_Cat
Well-Known Member
Basic Physics. Cant be done.
Have you actually tried it?
It can be done and it does work (see my previous post - and can add that in our own boat a fluxgate inside the boat, unadjusted for deviation, agrees very well with both the external fluxgate and the standard compass). There are plenty of documented cases where people have installed fluxgates within a steel boat.
As I said, I would not rely upon it myself due to the unpredictability of the environment over time. The strength of the earth's magnetic field within a steel boat may be defeated by basic physics, but advanced physics does not stand in its way /forums/images/graemlins/smile.gif.
John
Have you actually tried it?
It can be done and it does work (see my previous post - and can add that in our own boat a fluxgate inside the boat, unadjusted for deviation, agrees very well with both the external fluxgate and the standard compass). There are plenty of documented cases where people have installed fluxgates within a steel boat.
As I said, I would not rely upon it myself due to the unpredictability of the environment over time. The strength of the earth's magnetic field within a steel boat may be defeated by basic physics, but advanced physics does not stand in its way /forums/images/graemlins/smile.gif.
John
tome
Well-Known Member
We fit fluxgate compasses on steel ships all the time without major problems. Best results are to get them a few metres away from the hull/deck, eg on mast or pole.
