Sestral Moore Compass advice please

[Bernadette]

Ive got the opportunity to purchase a Sestral Moore compass.

I had one on each of the previous yachts and found them to be more than ideal and suitable to my needs. In short, I like them!

Whilst I initially planned not to use the same again, Ive changed my mind and will keep with the relatively short tradition over the past two boats and install the same on the new build.

The compass I had a look at today is in reasonable condition but it needs a new light (incl plug) which Im certain I can source over time on-line.
It needs a really good clean up and the hood doesn't bed down passively on the central retaining pin as it appears to be "warped". Maybe the cover has suffered damage or the metal has changed shape or 'grown' much the same way aluminium does. ....????

I know I can clean up the compass and get it repainted so Im not worried about refurbishing it in that regard.

Of greater concern though is the rather large bubble the compass has. This measures about 40 mm x 15 mm. I think it must have a leak someplace but cant be sure. The card itself is in perfect condition.
Im sure I could get the fluid topped up or replaced but I have less confidence in knowing what to do if it has a leak.
Swing motion is likewise unaffected.

Can anyone offer advice on my options regarding the bubble please? Any thoughts on the hood issue as well??

[Andrew Craig-Bennett]

Re: Sestral Moore Compass advice please

The liquid as you probably know is « Bayol ».

Here’s a supplier:

https://www.lasaero.com/products/article/B01SJ42A7

However I would worry about the leak; something has failed for the leak to be present; it could just be the filler plug seal or it could be something really serious like a crack in the diaphragm.

If you have a good repairer nearby she/he can fix it but my advice is to keep looking as these compasses do come up regularly on ebay.

[wizbang 13]

Re: Sestral Moore Compass advice please

Drill a hole in the bottom and let the rest of that pesky liquid the heck out of there .
that’s how I cured my bubble problem

[Andrew Craig-Bennett]

Re: Sestral Moore Compass advice please

Drill a hole in the bottom and let the rest of that pesky liquid the heck out of there .
that’s how I cured my bubble problem

Should your advice here be cross referenced to your advice here:

I have not looked at a compass in 20 years.

[Bernadette]

Re: Sestral Moore Compass advice please

Drill a hole in the bottom and let the rest of that pesky liquid the heck out of there .
that’s how I cured my bubble problem

yeah but no thanks. not helpful ...

[Bernadette]

Re: Sestral Moore Compass advice please

The liquid as you probably know is « Bayol ».

Here’s a supplier:

https://www.lasaero.com/products/article/B01SJ42A7

However I would worry about the leak; something has failed for the leak to be present; it could just be the filler plug seal or it could be something really serious like a crack in the diaphragm.

If you have a good repairer nearby she/he can fix it but my advice is to keep looking as these compasses do come up regularly on ebay.

Andrew, as I don't know about the component parts of a compass, is the diaphragm likely to be expensive to replace (if this is even possible)?

[Andrew Craig-Bennett]

Re: Sestral Moore Compass advice please

Andrew, as I don't know about the component parts of a compass, is the diaphragm likely to be expensive to replace (if this is even possible)?

Bernadette,

I will have to take a look at my Moore, tomorrow all going well, if not, at the weekend. Most Sestrel compasses have a facility to allow the liquid to expand and contract and this is often in the form of a thin brass bellows piece. But although I have a Moore and like it I can’t remember how it is constructed!

Do you gave a professional compass repairer in Queensland?

Here’s an old thread from the ybw forum with some discussion:

https://forums.ybw.com/index.php?threads/sestrel-compass-and-refuses-to-seal.541561/

I’ll get back to you.

Andrew

[Bernadette]

Re: Sestral Moore Compass advice please

Andrew,

thank you so much for your help so far.

Im not certain there is anyone in Queensland who can repair a Sestral Moore. I would have to do an internet search. I seem to recall someplace in Australia at least that might be up to effect repairs. Obtaining parts may be an issue.

I know this might sound dumb: are old style compasses built too differently from newer styles?

I would think at this stage of having to send the compass to the UK to get any work done on it. Ive had mariners' clocks "repaired" by clock repairers before and they have caused more damage than effect any repairs.

I tried looking up the schematics for a Moore but could only find fairly rudimentary drawings. Nothing that explains the inner workings. Do yo know what material the diaphragm is made of?

Is the thin brass bellows piece you talk off at the top of the compass? I ask because the cover does not sit passively onto the central retaining pin. So Im wondering if the pin is central to the brass bellows you describe. It may have been let off to allow expansion and some fluid has leaked out????

On the compass Im looking at I can't tell whether the central pin is at its correct height. Its approximately 3 mm below the height of the cover when the cover is positioned above the compass.

I have the seller waiting on my decision to purchase. I guess I could offer less than asking price given all this uncertainty. However I suspect the seller will just hang onto it and sell to someone who just wants the compass as a desk top ornament which in my opinion is a real shame.

[Bernadette]

Re: Sestral Moore Compass advice please

Andrew,
did you know there is a rather 'industrial' type compass (Sigma) very similar to the Sestral Moore made by Cassens and Plath. I haven't got a price on one yet.

[Canoeyawl]

Re: Sestral Moore Compass advice please

The older brass compasses used a brass (or bronze) diaphragm under the card support pin that allows the fluid to expand and contract with temperature change. They fail (crack) eventually, leak fluid and let air in. And then your compass is pretty much shot...
I have fiddled with a few and even had one I was emotionally attached to professionally repaired. Repairing the crack using solder worked, but I'm afraid that it made the diagram stiffer and when the fluid contracted it drew in air, probably around the face mounting ring.
(The diaphragm is pleated like a bellows)
Newer compasses may use different materials?

[wizbang 13]

Re: Sestral Moore Compass advice please

Should your advice here be cross referenced to your advice here:

yes,
the air compass with no bubble in the fluid was for the 20th century.
in this century it has been ignored

[Andrew Craig-Bennett]

Re: Sestral Moore Compass advice please

If you turn a Moore over you will see a cover plate (brass, painted grey or black) held in place by four round head screws, and a fifth larger cheese head screw. The larger screw is the filler and sits on a sealing washer. To refill the compass first put it in the freezer along with a syringe filled from the Bayol bottle, then undo the filler and top up using the syringe. The reason for getting it cold is that it reduces the risk of having a residual bubble.

The four small screws holding the cover plate on are brass, will be dezincified, and must be treated gently. Undo these and you will find the brass diaphragm.

I do emphasise - those tiny brass screws are the worst part of any Sestrel compass.

[Bernadette]

Re: Sestral Moore Compass advice please

Yesterday I finally managed to purchase a compass from an eBay seller in England. It appears to be in good condition overall. It should arrive here within the next two weeks so I'll be able to check its condition against the photographs! It does have a small bubble but Im not really worried by this.

It is however missing a few parts which Im having trouble sourcing (not surprisingly).

Mr Barry Phillips from BPSC is helping me with one particular part (Bearing Housing Locking Handle) but I still need the Lead Light Assembly (12v) and magnets. Fortunately the 'base plate' for the light assembly is intact and Barry tells me a compass adjuster should be able to supply the magnets.

If I get stuck for magnets, Im wondering if it's possible to turn down magnet material on a lathe to the required dimensions?

...and if anyone has a light assembly lying around they wish to sell...please let me know!

[wizbang 13]

Re: Sestral Moore Compass advice please

a small bubble
heh heh

[Bernadette]

Re: Sestral Moore Compass advice please

...thanks for the bastardised wishes...