Compass Adjustment

RobF

RobF

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I've got a Suunto F-116 Sail, which seems to point near perfectly when not in the binnacle, but about 10deg out when it's in situ.

I'm trying to work out how to compensate it, but cannot find any manuals or pictures of the bottom of this compass. I fear that a key component (the compensator) is no longer on my compass, but can't confirm this as the compass came with the boat. Any thoughts?

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maby said:
I thought it was done by attaching small fragments of magnet at points around the compass - am I wrong?

These guys did ours a few years ago - http://www.compassadjuster.co.uk/ - rather a long way from you, but they may be able to offer advice.
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Did the boat come with deviation cards that might show the problem , as when it sits in the binnacle their might be some interference from a heavy metal , or engine or other instrumentation near by.
 
moomba said:
Did the boat come with deviation cards that might show the problem , as when it sits in the binnacle their might be some interference from a heavy metal , or engine or other instrumentation near by.
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Am pretty sure the cause is a recently fitted chart plotter which is less than 250mm from the compass. It's only just been fitted and I'm not taking it out. I want to adjust around it. There are no deviation cards or compass manuals which came with the boat.

To be clear I want someone to tell me how to adjust it and whether or not the compensatory bit is missing.
 
RobF said:
Am pretty sure the cause is a recently fitted chart plotter which is less than 250mm from the compass. It's only just been fitted and I'm not taking it out. I want to adjust around it. There are no deviation cards or compass manuals which came with the boat.

To be clear I want someone to tell me how to adjust it and whether or not the compensatory bit is missing.
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you will need a professional compass adjuster who will give you a new set of deviation cards , not sure its something that can be tackled on a DIY mode as it requires calibration
 
RobF said:
Am pretty sure the cause is a recently fitted chart plotter which is less than 250mm from the compass. It's only just been fitted and I'm not taking it out. I want to adjust around it. There are no deviation cards or compass manuals which came with the boat.

To be clear I want someone to tell me how to adjust it and whether or not the compensatory bit is missing.
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It's a pretty specialist task - otherwise there would not be professionals that can make a living out of doing it! The US government publishes their manual on the subject - https://msi.nga.mil/MSISiteContent/StaticFiles/HoMCA.pdf - it's 46 pages and quite technical...
 
Folks, I don't want to be rude, but I AM aware of a Compass Adjuster and the services they offer.
I am NOT looking for the services of a compass adjuster
I AM looking for someone who can tell me whether the compensator for my compass is missing.

If I need to employ the services of a Compass Adjuster I may as well use the money to buy a new compass (complete with user manual and known compensator) and do the job myself. I appreciate I won't quite get the accuracy achieved by a professional but I am confident that I will get something that's good enough for me.
 
RobF said:
Folks, I don't want to be rude, but I AM aware of a Compass Adjuster and the services they offer.
I am NOT looking for the services of a compass adjuster
I AM looking for someone who can tell me whether the compensator for my compass is missing.

If I need to employ the services of a Compass Adjuster I may as well use the money to buy a new compass (complete with user manual and known compensator) and do the job myself. I appreciate I won't quite get the accuracy achieved by a professional but I am confident that I will get something that's good enough for me.
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Sorry but your OP was not clear it did not ask is my compensator missing, it was rather an open question , and not to sound rude, a compass is a key component of a boat ,to say its good enough for me when it could be 10 degrees out because you have not got any deviation cards and have not worked out the deviation or how much magnetic interference is on your compass seems to me illogical , yup its your boat your life but remember there are others that are out there using the water assuming that your compass is accurate
.just my thoughts
P.S why do you not look up your make of compass on the internet and do a good search especially on images and video something might turn
 
moomba said:
Sorry but your OP was not clear it did not ask is my compensator missing, it was rather an open question , and not to sound rude, a compass is a key component of a boat ,to say its good enough for me when it could be 10 degrees out because you have not got any deviation cards and have not worked out the deviation or how much magnetic interference is on your compass seems to me illogical , yup its your boat your life but remember there are others that are out there using the water assuming that your compass is accurate
.just my thoughts
P.S why do you not look up your make of compass on the internet and do a good search especially on images and video something might turn
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Yes, have done an Internet search for Suunto F-116 and can find no relevant images or Videos of it . I also can't find a manual for it on the Internet. With regards to your comment on my OP about not asking if my compensator is missing, I have to confess that I thought the bit which read ...I fear that a key component (the compensator) is no longer on my compass, but can't confirm this as the compass came with the boat. was pretty clear - but apologise if it wasn't.
 
It looks like information on that model is in short supply - I believe that Suunto pulled out of the marine compass market about ten years ago. I still think it may be worth calling the adjusters that I mentioned - just to ask for advice. Tell them that your compass is very inaccurate and you are trying to decide whether to have it adjusted or simply replace it. Also tell them that you think it may be missing a component and ask if they know what the compensator on that model would look like and where it would be - you don't want to waste a callout fee to get them to come to your boat simply to turn up and tell you that the compass is beyond repair!
 
maby said:
It looks like information on that model is in short supply - I believe that Suunto pulled out of the marine compass market about ten years ago. I still think it may be worth calling the adjusters that I mentioned - just to ask for advice. Tell them that your compass is very inaccurate and you are trying to decide whether to have it adjusted or simply replace it. Also tell them that you think it may be missing a component and ask if they know what the compensator on that model would look like and where it would be - you don't want to waste a callout fee to get them to come to your boat simply to turn up and tell you that the compass is beyond repair!
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According to https://www.andrewscompass.com/suunto.html, Suunto stopped making marine compasses in mid 2011 (I really have tried to look this up on the Internet). I have also searched the Suunto support site for this compass, but can't find it (looks like they are focussed on selling their new products rather than supporting legacy products). If there's no-one on this forum who is familiar with the F-116 I may contact Suunto directly as they are reputed to have good customer support.
 
RobF said:
I may contact Suunto directly as they are reputed to have good customer support.
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There you go! Close to RTFM.....

But you are not, if I read the post correctly, the 'customer'. So why, pray, do you expect that respected manufacturer with whom you do not have a contract for supply or service to spend time on resolving your concern when a respected professional - or more than one - has been ignored by you.

You clearly want professional-level skills to help you with your concern, yet seem wholly unwilling to pay such a skilled tradesman for his time, skill and judgement.

What else is there in life where you believe the rest of us owe you a living?
 
Is it worth checking that all electric wiring in the vicinity is twisted, to reduce EMF ? Also, I have come across compasses which deviate when adjacent instruments are switched on or off.

I can see an E-W mark, so compensation is available. Any screw holes on the side of the compass ?

EDIT

In pic 2, is that a screw head ?
 
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Those sticks projecting from the back look like they might have square ends. Could they be adjusters? I noticed the E-W marking too. I would expect one adjuster for E-W and one for N-S but there appears to be three. Could one be for off centre mounting?
I adjuster a Plastimo compass myself. It was 15 degrees off on some headings so I couldn't make it much worse. Got it down to within 5 degrees when compared with my hand bearing compass. It's not particularly difficult; if the sticks turn and affect the compass reading then I would have a go.
 
It has got both E-W and N-S markings. As sarabande asked, are there any holes on the sides of the compass? If there are I would expect them to be at the top and on the right of the first picture.

I see no harm in asking Suunto tech support for advice.

(It's equally difficult to find information on Plastimo compass adjustment, but I have at least worked out which hole is likely to compensate for my 10 degree error on N and S headings. I asked their support desk about something else to do with my compass - and I am the original customer - but didn't even get an automated reply.)
 
Years ago I had a Sestrel compass and a lot of deviation from a nearby bracket. Rather than move the bracket iset about adjusting the compass. It didn't have built in magnets but slots in which to slide small rods of different strengths. In principle, if I got it right for N-S and E-W the rest would fall into line, and the result was pretty good. With modern compasses and built in magnets it would be hard to work out what was going on and I would need reference to a manual for the compass before starting.
 
It seems likely that there were 4 posts, and that one has sheared off. It is also likely that those posts were used to mount a 'compensator carriage' onto which compensator magnets were attached and adjusted, for E-W corrections, and for N-S corrections.

There are many books on compass correction. From my bookshelves, one that might prove helpful is 'Practical Guide To Compass Correction' by George Reid/Waterline.
 
RobF said:
I've got a Suunto F-116 Sail, which seems to point near perfectly when not in the binnacle, but about 10deg out when it's in situ.

I'm trying to work out how to compensate it, but cannot find any manuals or pictures of the bottom of this compass. I fear that a key component (the compensator) is no longer on my compass, but can't confirm this as the compass came with the boat. Any thoughts?

View attachment 74417View attachment 74418
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This info says " All Suunto medium size compasses in the 95 & 116 series are supplied complete with a compensator that can be easily adjusted by hand, without the need for non-magnetic tools. "

https://www.azzisport.com/F-116-SAIL-Compass-Suunto

So the compensator may be missing as you say.

This may help

https://issuu.com/marinemegastore.com/docs/meridian_zero_catalogue/69
 
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zoidberg said:
It seems likely that there were 4 posts, and that one has sheared off. It is also likely that those posts were used to mount a 'compensator carriage' onto which compensator magnets were attached and adjusted, for E-W corrections, and for N-S corrections...
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I think that's where I'm landing too. The posts are not adjustable and therefore I think this was the part of the mounting for the compensator.

Rogershaw said:
This info says " All Suunto medium size compasses in the 95 & 116 series are supplied complete with a compensator that can be easily adjusted by hand, without the need for non-magnetic tools. "
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Roger's highlight also useful. It's not at all obvious or easy to adjust by hand. The 3 posts are fixed, and it does look like one has sheared off. Again, leading me towards Mr Zoidberg's conclusion.

Thanks also to Messrs Sarabande, DJE & andygc. I've double checked and there is only one obvious screw/hole and that is used to enable the sphere to be topped up with oil. There are no other slots or magnets on the compass (or if they are, they are incredibly well hidden).
 
RobF said:
Am pretty sure the cause is a recently fitted chart plotter which is less than 250mm from the compass. It's only just been fitted and I'm not taking it out. I want to adjust around it...
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This might be a dumb question, but does your chart plotter have a constant effect on the compass - or does it depend on what its doing and how much power it's drawing?
 
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