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Compass


Megwyn

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I was out on RO today, and noticed that the liquid inside the compass is about half way up the bowl.

 

I am certain that it was fuller on the weekend.

 

Also, the compass ball itself looks like it has had one too many Mt Gays.

 

Is the liquid an oily petroleum product?

 

Can you refill them, or do I need to purchase a new one?

 

Thanks

M

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You can fill them, and it is usually Mineral oil, but if it has leaked, it will only continue to. Only worth fixing if it was real expensive.

 

Well - it came with the boat - so I don't know how much it cost originally.

 

Do you have to take them out to fix them?

 

Thanks Wheels

M

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Best solution Megwyn is to remove the compass (not a real biggie usually) and send it/take it to the premier compass repair dude in Bayswater. Not only can he repair/refill compasses, he can swing them and do corrections too.

 

The guy's name is Dave Schafer and his business is

Compass & Sextant Specialists

52A Bayswater Ave

Bayswater

Auckland

ph 09 445 3336

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Best solution Megwyn is to remove the compass (not a real biggie usually) and send it/take it to the premier compass repair dude in Bayswater. Not only can he repair/refill compasses, he can swing them and do corrections too.

 

The guy's name is Dave Schafer and his business is

Compass & Sextant Specialists

52A Bayswater Ave

Bayswater

Auckland

ph 09 445 3336

 

Thanks Grinna - you don't know anyone really good down Tauranga way do you?

 

M

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Dave is the dude for compasses but he could well recommend someone in the BOP for you. Before you get too carried away, first check for any obvious sign of leakage underneath it. If nothing obvious and it is a good quality compass it may have lost the seal in its air trap (probably not the correct term). Try dismounting the bowl and gently turning upside down then right way up again. If this solves the problem it may be worth getting it checked and serviced anyway as it is generally pretty cheap. But please, do not top up with mineral oil.

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OK - thanks PW - will look at how to remove the dang thing this weekend.

 

M

On second thoughts, you may not need to dismount. You may be able to turn the bowl right over on the gimbals so try that first. Watch out for the light wiring.

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....either oil or alcahol....

clear babyoil or Gin/vodka ...

 

Told to me by a profesional compass adjuster.

I sucsesfully restored a compass with baby oil. The trickiest part was the "burping" of all air. Letting all the air settle out of the oil over a few days and then finaly doing up the fill bung while keeping the unit over flowing.

Not that harder job, and it still works (8 years later) just fine. The crazing of the clear dome , due to it not having a cover has done the most damage.

polishing with toothpaste made a big differance but I wouldnt do that on an expensive one !!

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They stopped using alcohol many years back, too many desperate sailors drinking their compasses. I think Dave said they generally use a very refined light oil these days. Idler probably has it right with baby oil or very similar.

 

A huge number of places you take your compass to get fixed only send them to Dave anyway. I'll probably see Dave in the next day or 2, he lives close as and we chat often. I'll ask if refilling the fluid can be a DIY and if so using what.

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...sorry should have been a bit clearer..was posting on the run....

yep alcahol was used in very old compass....I only mentioned it becuase the two fluids are not compatible. The internal finishes can be disolved by puting the wrong fluid in. If you wanted to guess though it will be oil.

If in doubt put a small amount on a piece of paper and see what it does. The alc will mostly evaperate leaving a small stain. The oil will be just like a fish and chip wrappper.

 

If it is alc...it is going to be quite valuable to an antique store and not for your boat. The reason for changing was more about the seriously better "slow damping" effect of oil rather than sailors attempting to get pissed on a few mm of alc. ...especialy since the act of doing such was cause for "instant court before the mast with no other option but death by hanging"...

 

To compromise the safety of a vessel and its crew always had one outcome ........hhhmmm maybee we should bring it back....

 

Back to the practicle...(I need to find my old notes but anyway) a lot of more modern compass have a rubber bellows on the underside of the compass. This takes up the expansion and contraction of the fluid when the temp changes.

 

Going back to my previous post...when all air has been burped....a very light compression on the bellows with a single finger while tightening the fill bung gets rid of that air bubble. This should be done on a warm day (or room) so that the bellows is never expanded beyond its full extension and the causing a breach in the seal on a very hot day.

 

This is general advice :D

 

oh and as a point for another post....

unless you seriously have done a little coastal nav study (which you should) be carefull using your compass..

If you dont know what "variation and deviation " is and how to apply it...GO FIND OUT NOW !!

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:D

 

Thanks Idlerboat - excellent advice, and am looking forward to hearing if I can fix it myself.

 

Having been sailing now for a mere 6 years, and never having a mounted compass on our boats, I was kinda looking forward to practicing my nav skills with it :)

 

M

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David Schafer, is featured in Boating FEB 2012 edition. A very informative article Page 92. One quote that sticks out though is " I've worked on compasses that have been filled with all manner of fluids- Johnson's baby oil, gin ,diesel,turpentine, kerosene -you name it. Restoring a beautiful old piece that's suffered such indignities is almost impossible"

I would defer to an expert like David in these cases and get the job done properly.

My ten cents worth cheers

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yep....and if you have a "beaytifull old piece" I would agree...fact is...most are not...and most beautiful old pieces are not very accurate....and they are worth more than your ten cents in an antique store.

Fact..so called restoration may devalue their sale price.

 

Point in question...one of the boats that I am dealing with at the moment dosnt even have a heading line inside the binacle...depending on what angle you look at you could be ten degrees out....but it is a beautiful old piece and should stay on the boat (with a new hand held as the main compass)

They should be restored....maritime history gets smaller by the day.

 

There is a whole range of 70s/80s compasses that are now suffering the effects of age. You can get a few more years out of them with a bit of home TLC...but to be blunt...the cost of employing a compass adjuster or marine instrument specialist is just not worth it..

These guys go on to big steel ships and do the adjustment and reports as part of the boats ongoing servey requirements.

Most of the simpler compasses have no adjustable compensators...it leaves bugger all to play with. Mainly fixing the seal and burping, realigning with the boats heading, and making a deviation chart. (To this last point...how many boats do you know, that have an active (writen in the last 12 months) deviation chart ?...

 

 

OR have a go yourself...

 

as to the article you refer too...it is always possibe to come up with an argument to "get a proffessional"

 

I maintain that serious offshore sailors ARE THOSE PROFFESSIONALS they seek information and learn abilities to be able to repair and maintain the equipment as much as possible on their vessels in circumstances of remote locations and remote finances...it may not be perfect but they sail....

 

Finaly...I am a practical man. The rules that state that a small craft must have a fixed compensated compass in place are crap !

If you doubt me..try steering a course on a dark night by compass alone and then check it back on your chart plotter.

Next...for coastal nav...an accurate hand held bearing compass is far easier than a fixed ships compass. Remember in that case it is the bearing to a fixed point that matters NOT your ships heading that allows you a fix.

A small water tight bag with a handheld GPS and a reasonable quantity of spare batteries (ever tried to take a ships compass off its pedestal) will keep you far safer than a nicely polished brass number....

 

Huuurumpppfff....My $250 worth !

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Most of the simpler compasses have no adjustable compensators...it leaves bugger all to play with. Mainly fixing the seal and burping, realigning with the boats heading, and making a deviation chart. (To this last point...how many boats do you know, that have an active (writen in the last 12 months) deviation chart ?...

 

:oops: do you mean a chart showing annual deviation? Or is this something new I can learn?

 

OR have a go yourself...

 

I maintain that serious offshore sailors ARE THOSE PROFFESSIONALS they seek information and learn abilities to be able to repair and maintain the equipment as much as possible on their vessels in circumstances of remote locations and remote finances...it may not be perfect but they sail....

 

Yes - so how do I fix my compass - which is not very old - myself? I too am a DIY kinda gal.

 

M

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A deviation chart is a list of the measured deviation of your particular compass in its normal installation for all the different directions. For instance, your compass in its normal mounting spot may be out by 3 deg E when the boat is heading NW and it may be out by 2 deg E when the boat is heading W, etc.

 

To develop a deviation card you "swing the compass". You go out and run the boat along known headings (transits that give you particular headings) and read off the compass value. You build up a list of deviations for all the major headings and apply those errors to any compass readings you calculate or read off the compass.

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