Empty compass??

Eeyore

Eeyore

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Location
Kudat, Malaysia
www.yachtrhumbdo.co.uk
I have a Sestrel Major (old type) steering compass, the card of which, in anything but a calm sea, swings wildly. When I removed it from the pedestal for a lighting problem, I noted that when looking 'through' the glass bowl from side to side, it appeared to be much less opaque than others that I have seen. I'm now wondering if there is in fact, any oil inside it at all. Does anyone know how I can check for sure - without resorting to dismantling it (and possibly losing a full bowl of oil!), and secondly does anyone know how to top up the oil, as I can see no way of doing so at present.
All comments welcome!!
 
G'day Eeyore,

Have a look at the underside, look for an area covered in a sealing compound, dig it out and you should find a small screw or threaded bolt.

Keep this small hole at the highest point and add oil till it is full, replace screw/bolt and re seal.

All done.

PS you may have to find out what fluid has been used first, because mixing it with some 'other' oil or fluid may destroy it.

Take care.

Avagoodweekend......
 
As said it is very important that you use the correct fluid. Not only could the wrong fluid not be miscible with the old but it could strip the markings off the card or destroy the seals.

I would suggest that you contact a compass repairer eg http://www.bpsc-marine.co.uk/ who occasionally visits these forums
 
It does sound empty, I remember finding the same with the compass on my old Seafix RDF. Don't forget to check for where the fluid leaked out as well.

I found that the fluid for mine was some esoteric BP number, but after ringing around I eventually spoke to someone in the research division, who confirmed it was simply a high grade paraffin and sent me 100ml for free (it usually comes in 45 gallon drums). Other compasses are oil or alcohol filled, so it pays to find out what it is first.
 
Get it to a compass repairer, in the long run it will be cheaper and easier, believe me, been there done that! Doh!
 
All Sestrel Compasses are now serviced / handled by :

SIRS Navigation Ltd

Compass House - Bowes Estate

Wrotham Road, Meopham

Kent DA13 0QB England

Tel: +44 (0)1474 816320

Fax: +44 (0)1474 816321

http://www.sirs.co.uk/

I contacted them about the radiant Hand Compass I have that has a large bubble. After photos and serial # given - they identified the fluid ...

Be careful as fluid in Sestrels has changed a number of times during manufacture and care to identify correctly is essential.

Mine is Isopropanol Alcohol mixed with Distilled Water .... others can be White Parafin, another is Bayol which is £13.90 per litre ....... so not only care in what to avoid spoiling the compass but also keep costs down !

There have been reports of people using Clear Baby-oil which is heavier and damps the card even more than original. But in the forums that have mentioned it - they all agree that compass has to be dismantled, cleaned of old fluid before baby-oil added.
 
I asked the CAA area surveyer about this one time and he said use Gin. Another time on an old French compass in a Jodel aircraft I stripped off the letters by using alcohol. So as you say, Take advice from experts. It´s usually cheaper.
A
 
Thanks to all.

Refueller ......Yes I had found out that SIRS are now responsible for the Sestral make, and I have looked at the diagram shown on their website, which doesn't exactly tie in with the model I have. That diagram shows the fluid to be Bayol. I have e-mailed them for advice but no response as yet. Ironically, their office/workshop is about 2 miles from where I lived before setting off on this mad voyage!! The compass has always been as it is now, and I guess that if it is empty, then it's been that way since I've owned the boat. There is no trace of bubble(s) and nothing drips or runs down inside the bowl when it's inverted. I may just get a new one with a fancy coloured card /forums/images/graemlins/smile.gif and have done with it!
 
My compass (urania) needed topping up and i emailed BPSC and they recomended Isopar L if you can get it.(it still needs topping up)
 
[ QUOTE ]
I noted that when looking 'through' the glass bowl from side to side, it appeared to be much less opaque than others that I have seen.

[/ QUOTE ]

Do you mean more transparent??

If it is full of oil, it will appear more transparent than one which is empty, because the oil largely eliminates the reflection from the inside face of the bowl.

If it is empty, I would expect you to be able to pick up the inside surface of the bowl by eye. If it's full, you wouldn't be able to, and it will look like a solid sphere.

If it's full, it will focus parallel light into a concentrated spot on the surface of the bowl, if it's empty, it won't - The ideal light source for checking this is the sun, but it may be difficult to set this up because the card will probably block the light. Maybe try a torch through it horizontally? (You could probably tell by shining a laser pointer through it, as well).

[ QUOTE ]
All comments welcome!!

[/ QUOTE ]

Just as well!

Andy
 
Johnsons baby oil... I recvognised the smell so I used it to top up my Plastimo Contest with it 2 yrs ago and still perfect.

Buy a bottle for £2 and compare the smells. it certainly wont take the letters off the card.

You might find another use for the oil......
 
More transparent....less opaque.......is there a difference?

Sorry, it was the only way I could think of describing it at the time. Basically, it just 'looked' empty!!

Anyway, I've now figured out how to remove the compass from it's housing, have found the filler 'feed screw' and also a split in the lower diaphragm.

So, it is indeed completely empty as suspected. /forums/images/graemlins/mad.gif
 
[ QUOTE ]
More transparent....less opaque.......is there a difference?

[/ QUOTE ]

Not as far as I'm concerned /forums/images/graemlins/smile.gif

Good luck with getting it sorted.

Andy
 
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