Abstract: A dynamic breakwater system includes at least one and preferably a plurality of dynamic breakwater assemblies, each of which includes a baffle wall member which is pivotally mounted in a body of water about an axis which extends substantially transverse to the direction of wave motion and so that a lower portion thereof is submerged below the water surface while an upper portion thereof extends above the water surface, each baffle wall member being biased such that it has a tendency to move in a direction opposite to the direction of wave motion and wherein apparatus for damping the movement of the baffle wall member when the same moves in the direction of wave motion under the force of waves impinging thereon are provided.

Abstract: Vibratory drill apparatus is disclosed which is adapted for automatic self-balancing to compensate for variations in hardness of the material being drilled and/or dulling of the cutting blades which occurs during the drilling operation. The apparatus includes a tubular casing adapted to be connected to a rotating shaft and a drill assembly comprising a plurality of coaxially extending pipe members, each being located one within the other, the upper region of the drill assembly being received within the lower region of the casing. A drill head is defined at the lower region of the drill assembly. The pipe members are interconnected such that they are mutually fixed to each other for simultaneous rotation about their axis and such that each pipe member is free to move in the axial direction relative to the other pipe members.