If it is similar to a Danforths or Ritchie compass, there is a fill hole on the underside. The gasket around the screw gets eaten away by the fluid so that is probably the source of the leak. Inspect and clean to make sure. Ritchie compasses have their own fluid which you can purchase. Danforths use mineral spirits (I believe). Not sure about Olympic?? Generally, they are fixable - do some research on internet.
Mandolin, Bayfield 36 out of Rock Creek, Chesapeake Bay.
I experienced that with a previous boat. Our compass had a diaphragm that sprung a leak. The manufacturer sold me a replacement diaphragm for under $10, but they wanted me to send the compass in so they could replace it, saying that a user could never get it filled enough to avoid a bubble.
I figured I didn't have anything to lose by trying it myself. I overcame the bubble problem by replacing the diaphragm and then taping a piece of string to it. As I filled the diaphragm with odorless mineral spirits, I pulled the string to expand the diaphragm. When I got it filled up, I screwed the plug in then released the diaphragm. Then I orientated the compass so the bubble would be under the screw in plug and I cracked the plug open until fluid came out then closed it again. That fixed my problem.