Abstract: A geophone is hung from a ball bearing in a pendular fashion so that it is free to swing in any direction. Because it is weighted, it will assume the correct positioning for operation. A clamp, carried with the pendular geophone in a seismometer designed for use on the ocean floor, fixes the geophone in a rigid position when a solenoid is actuated. After the seismometer is deployed on the sea bottom, it is desired to clamp the geophone into its assumed position. The solenoid is fired upon command causing the ball to be clamped. When the seismometer is recovered the angle of inclination with respect to the vertical it assumed at the time when the geophone was clamped can be determined by measuring the angle formed by the clamped geophone and a surface known to be vertical when the seismometer rests on a flat, horizontal surface.

Abstract: A release mechanism for use with an underwater exploration device such as one used to release ballast from an ocean bottom seismograph which includes primary and secondary release actuating devices. Ballast weights are secured to the seismograph by cables which themselves are secured by levers held immobile by a removable pin. The pin can be removed by the primary release actuating device, a rotary solenoid with linkage arms which produces a linear stroke, or by the secondary release actuating device, a coil spring held in compression by means of an electroplatable wire around and under the head of the pin, or both, allowing the levers to pivot releasing the cables and ballast weight. The mechanical advantage of the levers is utilized to allow a relatively heavy ballast weight to be held while requiring a much smaller force to remove the pin allowing its release.