I don't know how many Cherubini owners still have their original compass but I'll bet if they do, the compass is getting hard to see. Once I determined that it was the compass and not geriatric eyesight, I started looking for a fix. The problem on my 1983 Hunter 37 Cutter is that the binnacle mount for the compass is a white fiberglass affair that doesn't seem to fit any compass other than the Aquameter Gemini that came with the boat (I suspect these mounts were made by Hunter). The Aquameter Gemini is no longer made - Aquameter was sold to Danforth some years ago. I could have purchased a whole new compass and matching binnacle mount but the prices range from $460 for a Ritchie Navigator to $770 for a Danforth Constellation (which is the descendant of the Aquameter Gemini). Seeing as that amount of coin will buy a lot of boat beer, I opted to refurbish the original Gemini. There is a company in Massachusetts called Viking Instruments that will rebuild your compass or sell you the parts you need: http://www.vikingoptics.com/aqcopa.html . I opted for the latter and purchased a new dome and the accompanying o-ring for about $60 (see how much more beer I will have this summer?).
The first step is to empty all the oil from the compass. There is a big slot-head stainless steel plug on the bottom to remove. I intended to re-use the oil, so I poured it through a coffee filter into a clean quart-size mason jar. The oil was nice and clear, but I might have to top off with a drop of light mineral oil from the drug store, as some oil will be invariably lost in the process. Then the compass was split for cleaning. The first four phillips screw were obvious - they were the ones in the trim ring. The next four were hidden under the trim ring and were revealed once the first four screws and the ring are removed. On mine, the screws and nuts were in good shape but, if in doubt, soak them with a little penetrating oil first. With the eight screws removed, the two halves of the compass were carefully pried apart (I used a kitchen knive). Be careful of the o-ring joint as you don't want to damage it. Next the compass was fully disassembled and cleaned. I elected to not disturb the expansion diaphragm on the bottom and its housing with the corrector magnets. Everything was washed in warm water with mild dish soap and then rinsed and dried thoroughly.
Re-assemply is pretty much the reverse operation, except that the new dome and o-ring were used. Fill it with clean oil and rotate the compass as necessary to remove bubbles. Then top up the oil again and put the plug in. Something I read and am going to try is to place the whole compass in the freezer for a couple of hours (plug side up) and then top off again once the oil has "shrunk". This is supposed to guarantee no bubbles.
The only other job is to carefully remove the night light ring glued to the old compass dome. This was done very carefully, cutting and prying with a shop razor blade. Had I known that this part didn't come with the new dome, I would have ordered one. As it is, I will glue the old one on the new dome with a drop or two of Krazy glue.
As you can see from the pictures, the change is dramatic. Note that the compass has not yet been filled with oil in these pictures, so the compass card appears a bit smaller than normal due to lack of magnification. Compass rebuilding is a pretty simple job that is well worth it, IMO.
The first step is to empty all the oil from the compass. There is a big slot-head stainless steel plug on the bottom to remove. I intended to re-use the oil, so I poured it through a coffee filter into a clean quart-size mason jar. The oil was nice and clear, but I might have to top off with a drop of light mineral oil from the drug store, as some oil will be invariably lost in the process. Then the compass was split for cleaning. The first four phillips screw were obvious - they were the ones in the trim ring. The next four were hidden under the trim ring and were revealed once the first four screws and the ring are removed. On mine, the screws and nuts were in good shape but, if in doubt, soak them with a little penetrating oil first. With the eight screws removed, the two halves of the compass were carefully pried apart (I used a kitchen knive). Be careful of the o-ring joint as you don't want to damage it. Next the compass was fully disassembled and cleaned. I elected to not disturb the expansion diaphragm on the bottom and its housing with the corrector magnets. Everything was washed in warm water with mild dish soap and then rinsed and dried thoroughly.
Re-assemply is pretty much the reverse operation, except that the new dome and o-ring were used. Fill it with clean oil and rotate the compass as necessary to remove bubbles. Then top up the oil again and put the plug in. Something I read and am going to try is to place the whole compass in the freezer for a couple of hours (plug side up) and then top off again once the oil has "shrunk". This is supposed to guarantee no bubbles.
The only other job is to carefully remove the night light ring glued to the old compass dome. This was done very carefully, cutting and prying with a shop razor blade. Had I known that this part didn't come with the new dome, I would have ordered one. As it is, I will glue the old one on the new dome with a drop or two of Krazy glue.
As you can see from the pictures, the change is dramatic. Note that the compass has not yet been filled with oil in these pictures, so the compass card appears a bit smaller than normal due to lack of magnification. Compass rebuilding is a pretty simple job that is well worth it, IMO.
