Autohelm Personal Compass

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I inherited one of these with our boat. It's a battery powered fluxgate compass. It seems to have a timer button, a memory button and a big red central button which seems to page between the various memories (1-10) and displaying the determined bearing. It seems to have sights moulded on to the top of the casing (which is about 5" x 2" x 3/8ths")

1) I don't know how this thing works
2) I don't know what the memories are intended for

Does anyone have one of these and could maybe enlighten me?

tia

rob
 
It's a compass for taking bearings with. Point it at what you want to take a bearing of, press the button and it's held in memory. If you take a few bearings you can step through them and plot them on a chart.
 
IIRC you have to be careful to hold it level if you are to get accurate readings.
 
Tillergirl,

Thanks for your help. However Philip (below) has kindly provided a downloadable link so that'll save you trouble of copying.

Thanks again.

rgds

Rob
 
Further to the other answers.

It will take 9 bearings. If you do a 3 point fix, you can shoot each one 3 times and average tham for greater accuracy.

If you use it for taing a collision bearing, it doesn't forget the previous reading, but you might, it is sometimes difficult to remember which is relevant as you scoll back through the previous ones.

To repeat as mentioned elswhere, level on the horizon as you shoot, you will notice the reading deviates rapidly when it is other than level.
 
Re: Further to the other answers.

[ QUOTE ]
It will take 9 bearings. If you do a 3 point fix, you can shoot each one 3 times and average tham for greater accuracy.

If you use it for taing a collision bearing, it doesn't forget the previous reading, but you might, it is sometimes difficult to remember which is relevant as you scoll back through the previous ones.

To repeat as mentioned elswhere, level on the horizon as you shoot, you will notice the reading deviates rapidly when it is other than level.

[/ QUOTE ]I agree - except you might want to discard any obviously wrong readings. In the past when I used an Autohelm personal compass and it read something like 92 degrees, 93 degrees, 126 degrees, you can guess what bearing I might have used...
 
Re: Further to the other answers.

Exactly - I find mine a very quick way of getting bearings on a bouncy boat, especially at night - just point and click, click click then look at the readings afterwards. Even with an inexperienced user I would sometimes pass the compass up from below where I was doing the chartwork ask them to take 3 readings on, say, a lighthouse and a bouy then plot it all down below as long as at least 2 readings for each object were very similar.
 
Re: Further to the other answers.

Some features not yet mentioned:

Hold the button down for 2 seconds and it turns into a continuously reading compass.

Press 'TIMER' and 'MEMORY' simultaneously and the display light comes on.

There's no off switch, it times out.

Not so good for following a compass bearing for pilotage, because you can't use it to point in a specified direction.

Very useful for showing people the effects of magnetic dip!
 
Re: Further to the other answers.

[ QUOTE ]
Not so good for following a compass bearing for pilotage, because you can't use it to point in a specified direction.

[/ QUOTE ]Yes you can - Hold the button down for 2 seconds and it turns into a continuously reading compass. All you need to do then is have the compass pointing fore and aft.
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Re: Further to the other answers.

[ QUOTE ]
Yes you can - Hold the button down for 2 seconds and it turns into a continuously reading compass. All you need to do then is have the compass pointing fore and aft.


[/ QUOTE ]

If you read my post I said that you can use it as a continuosly reading compass. I was more concerned with pilotage, when one might be asked to keep a point on a given bearing. With a conventional hbc the easiest way to do this is to look along the bearing, see on which side of the bearing the point is, then alter course to bring the two together. With the Autohelm you can't do this (unless your eyes are on stalks so that one looks at the display while the other looks along the sights).
 
Re: Further to the other answers.

I am not sure what you are saying (I originally read it the same way as Cliff did), and if one reads your last post literally as keeping a fixed point on a given bearing, then you sail in a curve until one is heading directly for or away from it - so I don't think that is what you mean.

But every situation I can imagine you may mean is easily ennuff handled with an Autohelm Personal Compass, either just by taking individual bearings as approach the desired bearing at which a heading change is to occur and if turning onto a bearing then by transferring the bearing as a heading to the steering compass when arrive at the turn.

Perhaps you can elaborate. I use a Personal Compass in pilotage (although not so much these days as rely on the ECS) and have not come across a situation which has been a problem of any kind at all. But maybe there is?

John
 
Re: Further to the other answers.

It's not something I do terribly often but I read the post as one of those situations where you have obstacles on one side, or both and want to track down a fixed bearing towards a point.

I agree that it's more intuitive to use a conventional compass - if the needle goes right, I push the tiller right etc. but if using an electronic compass, I'd make use of the main compass to roughly sight along, then check every now and again with the electronic one.

I might mean left.
 
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