NavList:

George wrote:

It prompts a number of questions for Robert to ask
> himself.
>
>
> Does the compass share a panel with other instruments or
> components
> close by that could be generating their own magnetic field? I'm
> thinking particularly of a windsceen wiper motor, an inverter or
> anything else with a transformer in it, loudhailer, analogue
> meters.

Robert:

The compass is mounted about 8 inches above my instrument panel. I know, I know. That is one of the worst places but where else can I put it? I need it for steering and if it is someplace in the boat where I cannot see it from the helm and see it front on, then I might as well not have it at all. So I have to just compensate for this.

I believe Lu Abel commented that a good navigator is continually checking his already determined deviation errors as and when the opportunity presents itself. This is something I do.

George wrote:

> Is the compass nearer to the engine than it really needs to be?
> For
> example, can it be mounted close under the roof of the steering
> cabin,
> just as high up as it can possibly go?

Robert:

Any higher and I would not be able to see it to steer by.


>
> Is there any vertical mast or other component close by, that's
> made of
> steel?

Robert:

No

George wrote:

> Robert has to be aware that he is especially vulnerable to the
> effects
> of magnetised metal on board, because of his high magnetic
> latitude
> and the resulting weakness of the horizontal component. And
> particularly vulnerable to any nearby piece of vertical(ish)
> metal,
> that might come to an end near to the level of the compass

Robert:

This is why I do not rely solely on my magnetic steering compass

George wrote:
>
> I agree completely with Lars, that this compass installation
> indicates
> a particularly dangerous state of affairs. It needs some sort of
> urgent remedy. I would think hard about installing some sort of
> remote-reading compass up a stick, if it was my boat.

Robert:

I wouldn't go so far as to call this "dangerous" and in need of urgent remedies. When all is said and done, I know these waters very well. The compass is gravy. I use all of my instruments in concert: GPS, radar, sounder, compass, Mark 1 Brain, and Mark II eyes.

Believe it or not, I have been getting by just fine with my deviation card. I don't particularly like the fact that I have such extreme deviation values but what else can I do? The weak horizontal component of the magnetic field, coupled with internal magnetic influences from the boat no doubt have a synergistic effect on my compass. It is something I have to live with. Have not had any serious mishaps yet.

George wrote:
>
> I don't know how much change of latitude comes into Robert's
> voyaging,
> but he should be aware that any deviation table or magnetic
> correction
> will be local to his high latitude, and may need redoing if he
> journeys far South (or North).

A few hundred nautical miles south. Tops. Sometimes more.

Collectively, you are all driving me towards the warm and welcoming embrace of the strumpet goddess GPS.





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