Abstract: A transducer is disclosed for placing on top of a pile to indicate the force imposed on the pile by the hammer driving the pile. The transducer includes a body made of a material of a known modulus of elasticity. The body has first and second parallel surface areas on opposite sides thereof that face the pile and the hammer respectively. One of the surface areas comprises the co-planer surfaces of a plurality of spaced flexure elements that are spaced outwardly from the adjacent surface of the body. Each flexure element is connected to the body by supporting arms that are integrally connected to the flexure elements and the body to transmit the force imposed on the flexure elements to the body. Strain gauges mounted on the supporting arms measure the strain in the arms due to the force of the hammer from which the force imposed by the hammer on the pile can be determined.

Abstract: A system for controlling a plurality of subsea wellhead operators provides a dual set of operator controls having an electrical control cable and a pair of hydraulic control lines from the wellhead to a control center at the surface of the water. A primary set of electro-hydraulic multiplexed controls and a back-up set of hydraulic controls are each mounted in a separate control module on a base near the Christmas tree. When the primary set of controls fails operation is changed to the back-up set of controls by a signal from the surface control center. Defective control modules can be changed without removal of the tree cap as the controls are all outside the Christmas tree. Also, a defective primary control module can be removed while the back-up control module continues to control the operators in the Christmas tree.

Abstract: To detect the presence of certain types of hidden flaws within a material having an exposed surface, the surface is tapped at one location to produce sonic vibrations within the material. At another location, an acoustic receiving transducer is coupled to the surface of the material being tested. A characteristic of the electrical signals produced by the transducer which is indicative of the type of flaw to be detected is utilized to denote the presence of a flaw. A mobile foorm of apparatus which detects flaws while traversing the surface of the material and which indicates the location as well as the existence of the flaws is described.