Choice of compass for new steel boat

[peacock]

On a steel boat fluxgate compasses seem to need relative isolation from assorted electrical influences and also seem to require the transponder to be sited up the mast to avoid these influences. Siting the transponder up the mast could give rise to the pendulum effect. In view of these difficulties would it be easier to cope with the problems of installing a magnetic compass on a steel boat?

 

[jeanne]

We have a ferro boat, which is the same as steel with regard to compass deviation. It had a VDO fluxgate compass, which said in the installation instuctions that the sensor could be fitted up to three meters up a mast. We did just that, and the compass worked well for several years, very steady, and with no need for correction. Going round in a slow circle with the thing in correction mode was all it needed.
Then it failed, and I was so disgusted that something so vital could let me down, that I eventually replaced it with a Sestrel Moore magnetic compass. This is read from the edge, so it may be mounted on top of the main hatch garage, a reasonable distance from the steel, which stops at the side deckabout, four feet away. This also works well. It has facilities for correction, but I find it easier to swing the compass and use the resulting correction card than to correct the compass.
This comes from experience gained when the VDO failed. We were in Brazil at the time, so I did not even try to get the VDO repaired. I fitted a cheap ex-RAF bulkhead compass, which I had on board, which had to be mounted about 18 inches from the steel, and constructed a correction card which went up to 25 degrees of error on some headings. This was used all the way back to Bristol, and worked fine, even though this was before GPS, and we were on astro- nav.I did have an early Transit satnav, but that failed before the compass!
So we came home low tech,with a Walker trailing log, cost about 90 quid, an ebbco sextant, about 12 quid, a Davis Plastic sextant, can´t remember the price of that, and the Goverment surplus compass.
I think that I am saying that there is no need to worry too much, especially with GPS giving you an instant figure for your actual track.

 

[ebbtide11]

I have fitted out a steelboat with a fluxgate compass 3M up the mast which is working fine.

I tried a basic bulkhead mounted compass without much success - enormous deviations. I moved it to a position mounted on the sprayhood canopy frame directly over the companionway hatch and with the simple correcting magents supplied with the compass have managed to get the deviations down to around 5 deg.

 

[ianabc]

There is a thread about steel boat compass positions in the Metal Boat Society forum.

From what I read I believe that some metal boat owners have had success with the transducer being placed near the center of gravity of the boat, in the middle or near the middle of the boat!

We will duct tape the sensor within the boat and see before attaching the sensor on the aluminium mast.

 

[KellysEye]

We have a steel boat and KVH fluxgate compass which I believe is the compass American tanks use. The sensor can be mounted internally. We also have a magnetic compass that we compared to the fluxgate and made a deviation chart.