Bubble in compass

[patria]

We have purchased a new boat and are about to bring it back to ireland from Holland, there is a significant bubble in the compass and the surveyor suggests it needs replacing but we dont have the time before we depart Holland. What is the general view in relation to the effect compass bubbles can have on compass accuracy ?



<hr width=100% size=1>

 

[TaitTait]

If the compass card is still covered there should be no effect on the accuracy.The fluid is there to provide damping on the compass spinning but a bubble may make it trickier to read.If it is a binnacle compass it may be possible to top up the fluid.On mine there is a small fill screw on the side and the fluid is odourless mineral spirit.If you try this get a syringe from a chemists to use as a filler but check with the compass manufacturer to make sure you get the right fluid.You may also be able to get a replacement diaghphram which should be a lot cheaper than a new compass.
Tait Tait

<hr width=100% size=1>

 

[ParaHandy]

if its Weems & Plath (Merkur) white spirit is ok but i do have a bottle of the correct stuff which i offered to anybody some time ago ... send pm patria if you need it ...

just a note, i had a particularly obstinate bubble (the diaphragm had ruptured which may be your problem) which after numerous top-ups got to the size of a pin head and then suddenly it went .. probably hiding somewhere ... and as TT has said, the bubble won't cause any problems

<hr width=100% size=1>

 

[STEVEWARD]

Many years ago as a "newboy"in the RAF i was sent to stores to get a new bubble for a spirit level..............

<hr width=100% size=1>

 

[bpscmarine]

Let us know what make the compass is and we will let you know what the liquid is and what can be done in the long term to save the compass.
www.bpsc-marine.co.uk

<hr width=100% size=1>

 

[AndrewB]

None, as long as the card is still covered, though from some angles you may get a slightly distorted view.

Do not attempt to refill it until:

(a) You have worked out why it lost fluid and have stopped it happening again. If it is due to a failed expansion bellows then refilling could result in permanent damage.

(b) You know the type of fluid it uses. If you can't establish this from the maker, then as a precaution draw off a little more and mix it with the proposed replacement to ensure they are compatible. Most compasses these days use very light oil, Baby Oil may serve as a stop-gap.

P.S. Good luck with your new boat. Do check the compass against a few transits before you leave Holland, we wouldn't like to hear you've ended up in Norway!

 

[TaitTait]

Careful with baby oil which is basicaly mineral oil I made the mistake of "fixing " mine with it because I thought mineral spirit (paint thinner) could not be the right fluid.It took the Ritchie compass about 10 minutes to swing through 90 degrees.
Baby oil may be right for yours but check first.
TaitTait

<hr width=100% size=1>

 

[WayneS]

At a new Telcom appie, I was sent for a can of Dial-Tone.....



<hr width=100% size=1>

 

[WayneS]

I'm a post hijacker.

My Plastimo mini-contest is very discoloured and has a large bubble.

I want to open the whole thing up, clean it and refill, with the view that if it does not work, I will replace it.

Can you advide what I should refil it with.

Cheers

Wayne

<hr width=100% size=1>

 

[isandell]

It is not necessarily true that if the crad is covered you are ok.

I recently had a Contest that developed a bubble. It was not particularly large but on one trip, a big heel got the bubble under the card, which tilted and then stuck. No compass for the rest of the trip.

Ian

<hr width=100% size=1>

 

[Born_Free]

During my days as an engineer I've had to do this perhaps 6 or 7 times over the years, the first time I did it, I was under the instruction of an old lag (ie. the chief engineer and my boss at the time) and he told me that there were different fluids used by the various manufacturers and as we didn't know which one we had, he said the best course of action was to drain it all off, strip and clean the compass and re-fill with glycerine. I don't know if the manufactures would approve, but we never had any problems using it, and they always worked just fine afterwards. Incidentally the last one I did is the one on my own boat, which was done about five years ago, and is still Ok. As a bonus if you've any glycerine over afterwards, it's a great coffee sweetener, as we dicovered on a long passage when the sugar ended up sweetening the bilge water.

<hr width=100% size=1>Born Free!
Now I'm expensive

 

[AndrewB]

Never heard of that happening before! Usually the cards will float right up to considerable angles, to allow for heeling, this sounds like a design fault. Anyway, thanks for the warning.

 

[VicS]

I'm surprised at glycerine as a choice as it is very viscous.

One way in which you might be able to identify the correct fluid is by comparing refractive indicies. If you add a drop of a possible fluid to a sample of the original you will probably be able to see the two mixing if they are not the same because the refractive indicies are different but when you get the right one you will not see them mixing because there will not be a difference in refractive index. You will need a suitable vessel in which to experiment......a laboratory test tube would be ideal.

<hr width=100% size=1><font color=purple>Ne te confundant illegitimi.</font color=purple>

 

[deepchinablue]

y copass is a plastimo contest can you tell me what to use to fill it? <span style="color:blue"> </span>