Diver's magnetic compass has a needle mounted on two bar magnets with a lower conical sapphire bearing to ensure the needle quickly becomes stable after displacement

摘要

Diver's compass with fluid filled housing (1) with a central compass axle (6). The axle has a support (4) for two bar magnets (5) with a needle (13) placed on top of the bar magnets. The upper end (8) of the axle is mounted in an upper bearing while the lower axle is mounted in a lower conical bearing (9) that ideally made from a sapphire (11). The needle length is almost equal to the compass face diameter, and has a phosphorescent coating.