Optional capsule of compensation magnets which can be insereted into any Contest or Mini-Contest compass to provide for compass adjustment to compensate for magnetic interference (deviation) caused by steel or iron components of the vessel or fixed permanent magnets, such as those in loud speakers mounted near the compass. Magnetic compensation cannot adjust for transient or changing magnetic fields such as those caused by electric powered equipment or wiring (unless the power is always on or always off when the compass is in use). Or such as steel or iron components in a steering system or throttle linkage near the compass where the magnetic field changes when the steering or throttle is moved.