Abstract: Apparatus and methods for simulating the Earth's magnetic field. The apparatus includes a spherical structure having a rotational axis and a molten metal therewithin. A support is coupled to the spherical structure so that the spherical structure is rotatable about a rotational axis. Rotation of the spherical structure generates inertial forces in the molten metal. The apparatus may include one or more magnetometers operatively coupled to an outer surface of the spherical structure for measuring a magnetic field generated by the spherical structure.

Abstract: A submarine hull which has a half wing-like sail which projects vertically upwards, is provided with a keel-wing that also is half wing-like, but projects vertically downwards. By preference the keel-wing has a lower end plate and its main portion is trailed by two slotted flaps which can be pivotally moved in both directions about respective vertical axes in coordination with movement of the rudder of the submarine. If needed for permitting operation in shallow water or with the hull close to the bottom, the wing can be made to retract. The keel-wing not only counters the sail's rolling movement and keeps the hull upright, but also adds a side force to assist in tightening the turn.