Boat Forum / Building / June 2007

Sure, as long as you know what it is. Typically, they use mineral
spirits, but you should be able to tell by the smell.

We have Ritchies on two boats.   I was told they are not refillable,
though the big air bubble in one of them cries out for kerosene or
whatever.   But if you can open a screw to leak fluid, you can remove
the screw to refill.   .....Maybe?

Brian Whatcott   Altus OK

Sherwin,
You need to be very careful. Every manufacturer uses different fluids. The
one they use depends on the displacement and mass of the suspended unit.
Very often the fluid is a blend of different fluids to get the specific
gravity exactly correct for minimum load on the bearings. It is wise to call
the manufacturer and ask first. They are usually very helpful, but be
prepared for some significant cost. I had to refloat a Sperry Mk 47 Gyro
Compass which was suspended by a blend of Halocarbon 6.3 and Dow Corning DC
200. The compass takes about 2 liters. The HC 6.3 was $288 per liter and the
DC 200 was $200 for 3ml. The correct procedure is to weigh the gyrosphere or
in your case the rose assembly very accurately, then measure its exact
displacement in a calibrated vessel, then blend the fluids so that same
amount of fluid weighs exactly the same as the rose. If you get it wrong,
the rose sticks and the compass will be very inaccurate. Good luck.
Steve

Finally got some feedback from Ritche.  My Helmsman was older than their 2001
models, so it used oderless mineral spirits.  The terms are confusing, as some
local
stores sell it as paint thinner.  The differences are in the amount of refinement
of the
chemical, ordinary paint thinner being the least refined.  Although I purchased
oderless paint thinner, the Sunnyside company tech told me it was 100% mineral
spirits, because it was the oderless variety, which requires a high amount of
refinement.
Bottom line, be careful what kind of mineral spirits or paint thinner you use.
Oderless
types appear to be the safest.  After 2001, Ritche went over to a
new product, which is basically mineral spirits with certain additives to make the
compass rose respond better, etc.  You can mix the oderless mineral spirits with
their
newer fluid which sells for $9.95 a pint at West.  A quart of the Sunnyside
oderless paint thinner cost me about six bucks at my local hardware store.  The
main
trick is to get the fluid real cold (put it in your freezer for a few hours) and
inject that
into the filler hole.  As the fluid warms up, it expands and forces any remaining
air
bubbles out.  My compass repair worked out fine.

                                                       Sherwin D.

This won't help you, but is a wonderful excuse to tell one of our family
legends.

When my grandmother's sister was on her way to China (as a missionary, from
Finland), one day the captain called all crew and passangers on deck, and
announced that someone had again drunk the spirit from the compass. To
prevent any repetition of such an incident, he announced that he had added
enough rat poison to the spirit, to be sure that if anyone would try that
trick one more time, he would not live to repeat the offence!

- Heikki