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Sea Slacker
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My compass developed an air bubble (which seems to only be there on colder days, I guess the oil inside expands/contracts with temperature).

Is this something I could theoretically repair myself? The compass is as old as the boat and certainly not worth repairing commercially (I'd rather buy another one if that's the case)
 

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Just a fellow boater......

Hi : there is a way that I saw someone use (a hair dryer). In my very humble opinion, for such a crucial instrument, dont't fool around. A new Richy is not that expensive. Just replace it. So the holes don't line up fill "em and cover with the new base. Really don't gamble with something we all should depend. Hope this helps ....let me know Peter
 

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I have repaired a couple of compasses. It is fairly easy to do. Last time I ordered a new globe because the old one had very fine cracks that allowed air to enter on very cold days. Most compasses have a diaphram that compensates for expansion and contraction. I refilled with odorless mineral spirits bought at Lowes. I also bought new O-rings. That was last year and no new bubbles even over this past winter.
 

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My compass developed an air bubble (which seems to only be there on colder days, I guess the oil inside expands/contracts with temperature).

Is this something I could theoretically repair myself? The compass is as old as the boat and certainly not worth repairing commercially (I'd rather buy another one if that's the case)
This is something you can do. Over the Winter, I refurbished my 5" Danforth Constellation. It was doing the same thing. Many of these old compasses are fine machines and are well worth the trouble. This particular design has been manufactured by one company or another since the late '40s. I spent several hundred on parts and oil, but a new compass of similar quality would be at least 4 times that.

I'm a computer engineer and work for a defense contractor, so it doesn't matter to me who you use. However, I will pass on that I had a good experience buying parts and receiving good advice from Viking Instruments. Howard there is quite knowledgeable.

From personal experience I can tell you that if you have a leak, eventually the diaphragm collapses as much as it can and then the compass inhales air as it cools. Finding the leak is hard. The oil is volatile and evaporates as fast as a slow leak leaks, so you won't be able to locate it by looking for a wet spot.

I will pass on a few things from Howard ... buy compass oil, not mineral spirits, unless you are adding just a little bit to top up. If you disassemble the compass and replace all the liquid, he said that mineral spirits will work but will eventually darken as it leaches color from rubber parts. I'm not sure that's true, but I pass it on FWIW. In addition to Viking, West Marine and many others carry compass oil. Second, if you replace parts, getting the compass reassembled so it is tight can be tricky, depending on the design. Don't be afraid to ask for advice. If you have to replace parts, then once you have the compass together, filled, and you think it is tight, put it in the freezer to see if it inhales air.

If your leak is slow enough, you want to take the easy route and simply put more oil in rather than finding and fixing it. Remove your compass from its mounting and look for a screw with a rubber washer under it. Orient the compass so that the screw is on top then remove the screw to add the oil. I found a nasal aspirator for babies works pretty well for the task. Before you put the screw back in, jiggle and roll the compass around a little bit to get as much of the bubble out through the screw hole as you can. It's also a good idea to make sure the diaphragm has a little slack in it so that it doesn't rupture from expansion on hot days. Poke a finger in the diaphragm as you tighten the screw and push a little oil out as you close it. Needless to say, this operation can be messy. I did mine in a dish pan.
 

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Telstar 28
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IIRC, not all compasses were filled with oil. You really should check to see what the manufacturer, if they're still in business, recommends.
 

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My compass came with my boat from US when new. That's 6 year ago. I notice the compass card is alway incline to starboard. It'll still swing and gives good bearing but card is slanted. Should I do something or just leave it. Like I said, its been like this for last 6 years.
 

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If the compass is always inclined to starboard, there's a good chance it was installed too close to something, as the card really should be level, and if it isn't there's something interfering with it. I seriously doubt the card is not balance properly, since that is very, very, very unlikely with today's manufacturing techniques.
 

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We had the same problem and sent it to the factory for refurb. The cost was much less than I expected, I'm guessing maybe $50 and it looks as good as new.
 

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If your compass card has always been like this (i.e. you can't remember seeing it any other way) then the chances are the compass was manufactured for the other hemisphere.

The magnetic variation of the earth is such that as you proceed from far north to far south the compass card starts to lean. The compass manufacturer will glue a tiny weight onto the underside of the card to compensate for this and the compass will often display the lean tendency when going to the opposite hemisphere.

It sounds like you have a southern hemisphere compass in the northern hemisphere.

This is often evident in older compasses, I believe the later models don't do this.
 

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Good point.. I forgot that compass cards for the other hemisphere might also do this. :)
If your compass card has always been like this (i.e. you can't remember seeing it any other way) then the chances are the compass was manufactured for the other hemisphere.

The magnetic variation of the earth is such that as you proceed from far north to far south the compass card starts to lean. The compass manufacturer will glue a tiny weight onto the underside of the card to compensate for this and the compass will often display the lean tendency when going to the opposite hemisphere.

It sounds like you have a southern hemisphere compass in the northern hemisphere.

This is often evident in older compasses, I believe the later models don't do this.
 

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Sea Slacker
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Discussion Starter · #12 ·
IIRC, not all compasses were filled with oil. You really should check to see what the manufacturer, if they're still in business, recommends.
I doubt they are (and if they are - I doubt they remember) - it's been 37+ years :)
Actually I am thinking of replacing it. The compass has 5 degree gradations and I'd like something a bit bigger and a bit more precise. May be at the end of the season though - I have my hands full with projects and the boat is nowhere near water yet.
 

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If your compass card has always been like this (i.e. you can't remember seeing it any other way) then the chances are the compass was manufactured for the other hemisphere.

The magnetic variation of the earth is such that as you proceed from far north to far south the compass card starts to lean. The compass manufacturer will glue a tiny weight onto the underside of the card to compensate for this and the compass will often display the lean tendency when going to the opposite hemisphere.

It sounds like you have a southern hemisphere compass in the northern hemisphere.

This is often evident in older compasses, I believe the later models don't do this.
I guess as much. Think I'll just leave it as is since it still works. Thanks Andri.
 

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Some compass makers offer very reasonable repair or replacement services, so first call the maker.

Compass fluid varies, it may be alcohol, oil, mineral spirits, etc. If you put in the wrong one, you'll muck things up. If you want to top it up, ask the maker what the correct fluid is (many sell it) or ask them for the MSDS on the fluid tha tthey sell--they are required to provide an MSDS for any "chemicals" shipped interstate. And change the o-ring or other reason that your compass leaked, as well.
 

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I would think that the gimball would have enough weight to counteract in magnetic forces in a compass.
The "un-balanced card" is a known element in steering compasses. Here is a process of swinging a compass that about halfway down the page deals with hemispherical lean on the card. Here is a comment by Roy McBride:

"Every boat needs a compass if it intends doing coastal or offshore work,its not just a job of taking the new (or old) compass from its box and bolting it down,certain things must first be done,here are a few pointers (no pun intended)the first thing to check is if the unit you have is a northern or southern hemisphere compass? This is due to the pull of the worlds magnetic field being different at each side of the equator,this means the compass card will show a lean or 'pull' on a compass fitted in England but now having traveled to South Africa. Normally the card tilt is just a bother but in some cases the card can actually stick,then its a worry,assuming we understand that side of things we can move to the next issue."

And I could find many more - I'm just not interested enough. I'm also not clever enough to make up a story like that. :p

For the whole article on swinging your own compass see:

CKD Boats - Roy Mc Bride: Compass Swinging for yachts,you can do it yourself
 

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You are right!!! I guess that dip is a stronger force than I thought. I knew that dip affected compasses but thought that the gimball weight was enough. It is good to learn..thanks.
 

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I have run into ethylene glycol before.

Some compass makers offer very reasonable repair or replacement services, so first call the maker.

Compass fluid varies, it may be alcohol, oil, mineral spirits, etc. If you put in the wrong one, you'll muck things up. If you want to top it up, ask the maker what the correct fluid is (many sell it) or ask them for the MSDS on the fluid tha tthey sell--they are required to provide an MSDS for any "chemicals" shipped interstate. And change the o-ring or other reason that your compass leaked, as well.
As material compatibilities go, it is either petroleum (mineral oil) or aqueous (alcohol/glycol/glycol ether). So, does the existing fluid mix with water? Simple.

If it is aqueous, best dump it all and use fresh EG or glycerine, mixed 50/50 with water.
 

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The "un-balanced card" is a known element in steering compasses. Here is a process of swinging a compass that about halfway down the page deals with hemispherical lean on the card. Here is a comment by Roy McBride:

"Every boat needs a compass if it intends doing coastal or offshore work,its not just a job of taking the new (or old) compass from its box and bolting it down,certain things must first be done,here are a few pointers (no pun intended)the first thing to check is if the unit you have is a northern or southern hemisphere compass? This is due to the pull of the worlds magnetic field being different at each side of the equator,this means the compass card will show a lean or 'pull' on a compass fitted in England but now having traveled to South Africa. Normally the card tilt is just a bother but in some cases the card can actually stick,then its a worry,assuming we understand that side of things we can move to the next issue."

And I could find many more - I'm just not interested enough. I'm also not clever enough to make up a story like that. :p

For the whole article on swinging your own compass see:

CKD Boats - Roy Mc Bride: Compass Swinging for yachts,you can do it yourself
Does that mean you need two compasses if you sail in both hemispheres ?
 
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