Compass Repair

Compasses are normally filled with fluid to provide dampening for the card and provide stability of operation. Some compasses use mineral spirits as the fluid and others have talked of alcohol, glycerin and even kerosene. Whatever fluid is used, if it leaks out, then there is a problem!

Last summer my port compass started leaking the fluid out and it did not take very long before all the fluid was gone. I took the back cover off  and discovered the diaphragm that compensates for expansion was ruptured. I searched Ritchie and Sons's website and found an exploded view of my Navigator BN-202 compass as well as a list of parts. I determined what parts I needed and with a call to Ritchie, I had the repair parts ordered along with  a quart of their new filling fluid, Isopar L. Ritchie(who is in Massachusetts) sent me the parts where they arrived only four days after order via US Postal Service and without an expensive shipping charge! Kudos to them!

I disassembled the compass at the shoreside shops of Hermit Hill Rigging and cleaned the inside of the now cloudy dome. Reassembly was easy and the o-rings, diagphram and new LED lights were installed. Filling with Isopar L is messy. The fluid is first placed in the freezer for several hours(I assume to squeeze the air out). I tried a small funnel and spilled a lot of the fluid. I finally found a small tapered hose fitting from my vacuum pump and with a hose and the small funnel, finally accomplished the fill and excluded ALL the air.

The compass is ready for reinstallation on the boat. That only takes a few minutes and four little screws to mount, but a little longer to solder the wires of the new lights.

 The compass disassembled and the parts cleaned.

 Ready for filling. Notice how small the red compass card looks?

 The compass filled with cold Isopar L fluid and the air excluded. Now see how large the compass card appears now?

Filled with fluid.